10 best Postman alternatives for API testing in 2025 (hands-on tested)

I didn’t go looking for Postman alternatives out of boredom. I went looking because Postman, once everyone’s go-to for everything API-related, started to feel like an overstuffed suitcase for many users: heavy, sluggish, and expensive if you’re working with a team. 

For years, Postman was the industry’s darling, combining design, testing, and documentation into a single tool. But lately, its reputation has been slipping. Pricing changes, feature bloat, and performance hiccups have left many developers wondering if it’s time to pack up and move.

So, I spent the past few weeks testing out what could realistically replace Postman. I was looking for a tool that can handle the same range of API testing (REST, SOAP, GraphQL, etc.) without the headache. 

In this guide, I’ll walk you through the 10 best Postman alternatives I actually tried, complete with pros and cons, and some tips you’ll want to know before making the switch.

If you’ve been frustrated with Postman but hesitant about leaving, stick around. You might just find your next favorite API testing tool here.

TLDR: Key takeaways from this article

• Postman is great, but it’s not the only option. There are lighter, faster, and more specialized tools depending on your needs.
• Free and open-source options like Hoppscotch, Insomnia, and Karate are excellent for individuals and small teams.
• If you need enterprise-grade testing, CI/CD integration, or performance monitoring, tools like Katalon and Assertible are worth considering.
• Before choosing, ask about integration, scalability, pricing, collaboration, and support; the right fit depends on your team’s size, skillset, and testing goals.

Postman overview 

Developer	Postman Inc. (founded by Abhinav Asthana and team)
Year launched	2014
Type of tool	API development and testing platform
Top 3 use cases	Designing and testing REST, SOAP, and GraphQL APIs; automating API tests and integrating with CI/CD pipelines; & generating and sharing API documentation across teams
Who can use it	Developers, QA engineers, product managers, and even non-technical stakeholders collaborating on API workflows
AI capabilities	Postman recently introduced Postbot, an AI assistant that helps generate test scripts, debug requests, and suggest API workflows
Platform accessibility	Available as a desktop app (Windows, macOS, Linux), web app, and browser extensions, with cloud syncing across devices

Many users remember opening Postman for the first time and feeling like someone had finally given them a Swiss Army knife for APIs. Instead of juggling cURL commands in a terminal or passing endless JSON snippets around, they could design, test, and document everything inside one clean interface. No wonder Postman became the go-to tool for developers and testers over the past decade.

So, what exactly is Postman today? 

At its core, Postman is an API development and testing platform that lets you design, debug, automate, and document APIs in one place. It simplifies how we send HTTP requests (think GET, POST, PUT, DELETE, PATCH), validate responses, and manage multiple environments. Beyond testing, it doubles as a collaboration hub; developers, QA engineers, and product teams can share collections, workspaces, and even live documentation.

How it works

The workflow is straightforward. You spin up a request, set the headers, parameters, or authentication, hit send, and instantly see the response. 

From there, you can:

• Organize requests into collections for structured workflows.
• Switch environments easily with variables (dev, staging, prod).
• Automate testing using JavaScript scripts that check status codes, headers, and response bodies.
• Mock APIs to simulate endpoints while backend work is still in progress.
• Generate code snippets in multiple languages so developers can drop API calls straight into their apps.

It’s the kind of tool that scales from a solo developer tinkering with a REST API to a global enterprise running CI/CD pipelines.

What made (and still makes) Postman valuable?

1. Ease of use: A new user to Postman only has to sign up, download the tool, and log in to their account to get started
2. Simplified API: Postman users can begin their API journey quickly and effectively using Postman’s comprehensive platform and wide support for all possible HTTP methods.
3. Robust testing capabilities: Postman supports multiple testing environments, test checkpoints, and scheduling options.
4. Integration and collaboration: Postman Workspace is dedicated to real-time collaboration between teams with built-in version control. The tool integration ecosystem is growing, with major names constantly being added.

What Postman does

Feature	What it does
Request building	Create and manage GET, POST, PUT, DELETE, and PATCH requests with parameters, headers, and payloads.
Collections & workspaces	Organize related requests, collaborate with teams, and keep projects consistent.
Automated testing	Use JavaScript scripts to validate responses and run regression tests.
Mock servers	Simulate endpoints for early front-end development.
Documentation generator	Turn collections into shareable, live API docs.
Environment variables	Seamlessly switch between dev, staging, and production setups.
Monitoring & alerts	Run scheduled tests and receive alerts on failures.
Authentication	Supports OAuth, API keys, Basic Auth, and more.
Governance tools	Enforce best practices, improve API quality, and streamline reviews.
Postman Flows	A low-code automation builder for creating workflows and integrations.

Pricing

Plan	Price	Best for	Key features
Free	$0	Individuals or small teams	Up to 3 users API Client access 3 Packages 1-day collection recovery Spec Hub: 1 private API, unlimited public APIs Cloud integrations 25 collection runsFlows access50 free Postbot activities
Basic	$19/user/month	Teams needing basic API collaboration	Everything in Free, plus:  No seat limit30-day collection recovery 10,000 Mock Server requests Spec Hub: 3 private APIs, unlimited public APIs 10,000 Monitor requests Pay-as-you-go capabilities
Professional	$39/user/month	Larger teams, cross-org, and external partners	Everything in Basic, plus:Internal (private) workspaces Single & multi-partner workspaces Basic role-based access control Spec Hub: 10 private APIs 25 Packages 90-day collection recovery
Enterprise	Custom (annual only)	Organizations needing advanced security, support & control	Everything in Professional, plus:Private API Network SSO, SCIM & SAML Reporting & analytics Audit logs – User groups Advanced RBAC 100 Packages 100,000 Mock Server requests Spec Hub: unlimited private & public APIsCustomer success support

Why do you need alternatives to Postman?

Postman is powerful. It can design, test, document, and automate APIs all in one place. But when you zoom into daily workflows, you’ll notice the cracks. 

Here’s why people are making the switch:

1. Free plan restrictions
   • API creation limits: The free plan allows you to create only three APIs. This can be limiting if you’re working with microservices or multiple projects.
   • Collection runner limits: You only get 25 runs a month. Any serious testing schedule burns through that before the end of the week.
   • API and mock server call caps: 1,000 calls each per month may sound okay, until your app starts scaling and you hit the wall mid-project.
   • Limited flows: Just five flows means complex workflow automation is practically off the table.
   • Team collaboration limits: Only three collaborators per workspace on the free plan. Beyond that, you’re either paying or packing.
2. Complexity and learning curve: Postman has grown into an everything tool, but sometimes that’s the problem. The interface is busy, the workflows can be confusing, and new users face a steep learning curve.
3. Performance issues: On large projects, users have complained that Postman can feel sluggish. High memory usage and lagging responses make quick debugging sessions drag on longer than they should.
4. Testing limitations: Postman is strong for functional API testing, but doesn’t cover performance, stress, or load testing out of the box. Teams with broader QA needs often find themselves juggling multiple tools.
5. Scripting constraints: Postman supports JavaScript-based test and pre-request scripts, but debugging is limited, and advanced logic can feel clunky compared to more developer-friendly environments.
6. Collaboration roadblocks: Even with paid plans, collaboration can be challenging. Sharing setups, syncing across teams, and managing API versions can get messy especially when working across larger organizations.
7. Integration challenges: Postman doesn’t always slot neatly into CI/CD pipelines or other dev ecosystems. Its GUI-first design works against developers who prefer CLI-based, scriptable tools.
8. Dependence on GUI: If you’re a fan of headless workflows or terminal-first testing, Postman feels restrictive. Other tools offer more flexibility here.
9. Pricing confusion: Postman’s pricing tiers are, frankly, a little confusing. Teams often find themselves unsure of what’s included at each level, and paying more just to unlock basic features like collaboration or higher usage limits.
10. Other pain points:
    • High resource usage during simple tasks
    • Restricted mock response flexibility
    • No open-source transparency (which many developers value)
    • Limited browser integration for real-time debugging
    • Rigid rule automation compared to more dynamic alternatives

The 10 best Postman alternatives

The following are 10 solid alternatives to Postman. Each comes with its strengths and drawbacks. They are arranged in the order I tested them.

1. Insomnia. 
2. Hoppscotch. 
3. Katalon. 
4. SoapUI. 
5. JMeter. 
6. ReadyAPI. 
7. RapidAPI for Mac. 
8. LoadNinja. 
9. Assertible. 
10. Karate Lab. 

1. Insomnia by Kong [Best for design-first API development]

Insomnia is a collaborative API testing and debugging platform that makes designing, testing, and mocking APIs straightforward. With support for REST, GraphQL, gRPC, SOAP, and WebSockets, it brings multiple protocols under one roof. Unlike some heavy, cluttered tools, Insomnia focuses on clarity and usability, giving developers a sleek workspace for API design and debugging.

Now owned by Kong, Insomnia doubles down on design-first API development with strong OpenAPI support. Whether you’re testing a single endpoint or managing complex workflows, Insomnia streamlines the process, letting you focus on building quality APIs without the chaos.

It’s also developer-friendly, with scripting, dynamic variables, and a plugin system that extends its functionality. Teams can sync projects with Git, collaborate through workspaces, and share environments to keep workflows consistent.

How it works

You create requests (GET, POST, PUT, DELETE, etc.), configure environments with variables (like API keys or base URLs), and view responses with status codes, headers, and body. You can chain requests, validate responses, and even generate ready-to-use code snippets. For collaboration, Insomnia allows workspace sharing and Git synchronization, making it easy to keep APIs consistent across teams and environments.

Insomnia at a glance: 

Developer	Kong Inc.
Year launched	2015
Type of tool	API client for design, testing, and debugging
Top 3 use cases	API testing & debugging, collaborative API design, environment management
Who can use it	Developers, QA engineers, API designers, DevOps teams
AI capabilities	None (no native AI features as of now)
Platform accessibility	Windows, macOS, Linux

Key features:

• Open-source model: Community-driven with plugins and extensions to extend functionality.
• Flexible environment management: Define and switch between multiple environments with ease.
• Dynamic variables & scripting: Create adaptable API requests and manipulate responses.
• Efficient code generation: Generate code snippets in multiple programming languages.
• Workspace sharing: Collaborate with teams through shared workspaces and Git sync.
• Built-in version control: Track request history and modifications across projects.
• Import/export options: Migrate setups between projects and tools (Postman, Swagger, etc.).
• Multi-protocol support: REST, GraphQL, SOAP, gRPC, and WebSockets all in one place.

What I liked about Insomnia:

• Clean, intuitive interface with custom themes.
• Excellent GraphQL support with schema explorer.
• Strong plugin ecosystem for extended use.
• Smart organization of requests and workspaces.
• Open-source, developer-first tool that adapts to real workflows.

What I didn’t like about Insomnia: 

• Limited built-in collaboration compared to tools like Postman.
• No native load testing or advanced performance testing.
• It can feel heavy on older machines with large collections.
• Niche learning curve for scripting and advanced environments.
• Advanced team features are behind a paywall.

Ideal user/use case

Insomnia is perfect for developers and small to mid-sized teams who want a lightweight, open-source, and developer-friendly alternative to Postman. It shines when you need a design-first workflow, strong GraphQL/gRPC support, and Git-based collaboration, but you don’t need advanced performance testing or enterprise-grade collaboration baked in.

Pricing

Plan	Price	Best for	Key features
Hobby	$0/user/month	Individual developers or small projects	All API designing, debugging, mocking, and collaborationUnlimited collaborators (for 1 project accounts)Unlimited collection runs1,000 free mock requests, then $10 per 25,000 requests
Pro	$12/user/month	Teams that need collaboration and version control	Everything in Hobby, plus:Unlimited collaboratorsUnlimited organizations Native Git supportRole-based access control (RBAC) & permissions10,000 free mock requests, then $10 per 25,000 requests
Enterprise	$45/user/month	Large organizations with enterprise-level security & support	Everything in Pro, plus:Enterprise SSO (SAML, OIDC) & SCIMStorage control (Cloud, Local, or Git)Advanced RBAC for teams. Domain capture & invite control.Self-hosted API mocking Enterprise support Custom payment optionsUnlimited mock requests  Vault integrationsKong Professional Services

2. Hoppscotch [Best for speed and simplicity]

Hoppscotch (formerly Postwoman) is one of those rare open-source gems that feels like it was built for developers, by developers. It runs right in your browser, so you don’t need to download some massive installer just to send a single request. At its core, it’s a lightweight API testing client that supports REST, GraphQL, WebSockets, and more.

What makes it stand out, at least for me, is how fast and distraction-free it feels. Instead of wrestling with endless menus, I could quickly spin up requests, tweak headers, and see results in real time. And because it’s community-driven, it keeps improving without the pressure of enterprise-style feature fatigue.

Hoppscotch is also versatile in where you can run it: web app, desktop app, browser extension, or even as a self-hosted option if you want full control. It’s one of the smoothest ways to test APIs without the weight of a Postman-sized toolbox.

How it works

You open Hoppscotch directly in your browser or install it as a progressive web app (PWA). From there, you can create API requests (GET, POST, PUT, DELETE, PATCH, etc.), send them, and instantly view responses in a clean, real-time interface. You can also save requests into collections, share links with teammates, and manage environment variables to simulate different setups.

Hoppscotch at a glance: 

Developer	Community-driven (open source)
Year launched	2019 (as Postwoman)
Type of tool	API testing and development client
Top 3 use cases	Quick REST/GraphQL testing, real-time debugging, request sharing
Who can use it	Solo developers, small teams, open-source enthusiasts
AI capabilities	None (community may add AI plugins in the future)
Platform accessibility	Web app, desktop app (Windows, macOS, Linux), browser extension, self-hosted

Key features:

• Multi-protocol support: Test REST, GraphQL, WebSockets, and even Server-Sent Events in one place.
• Open-source and free: Completely free with an active, enthusiastic community behind it.
• Environment and variable management: Quickly swap between dev, staging, and production setups without rewriting requests.
• Request history and collections: Save, organize, and revisit previous requests for smoother workflows.
• Lightweight and instant access: No heavy setup; it works straight from the browser or as a progressive web app with offline support.
• Import/export flexibility: Bring in Postman collections, API specs, or HAR files and pick up where you left off.
• Real-time response view: Instantly visualize and validate responses with JSON support.
• Self-hosting option: Deploy on your own server for privacy and control.

What I liked about Hoppscotch:

• It’s lightweight and super fast compared to bulkier tools.
• Works right in your browser or as an installable app.
• Open-source and actively maintained by a passionate community.
• Clean, simple design that’s not overwhelming.
• Self-hosting support for teams that care about privacy.

What I didn’t like about Hoppscotch: 

• Limited team collaboration features compared to Postman.
• Lacks advanced performance/security testing options.
• Some complex authentication setups can feel clunky.
• Offline access requires installing as a PWA, which isn’t always seamless.

Ideal user/use case

Hoppscotch is best suited for solo developers or small teams who want a fast, browser-based API testing tool that covers the essentials. If you’re tired of Postman’s bloat and just want a quick, no-nonsense playground for your APIs, this is your best bet.

Pricing 

Hoppscotch is free to use for everyone. The platform offers paid plans with additional features and support. 

3. Katalon [Best for all-in-one test automation across APIs, web, mobile, and desktop]

Katalon is a comprehensive test automation platform built to simplify API, web, mobile, and desktop application testing. Unlike tools that only focus on one area (e.g., APIs like Postman), Katalon brings everything together in one platform, offering both no-code/low-code and advanced scripting options. It’s designed to cater to beginners who want quick test creation as well as seasoned QA engineers who need powerful customization.

How it works

Katalon offers two main layers:

• Katalon Studio: A productive IDE where you can build API, web, mobile, and desktop test cases using either record-and-playback, keyword-driven testing, or full coding in Java/Groovy.
• Katalon TestOps: A cloud-based management and reporting hub for scheduling, running, and analyzing tests across CI/CD pipelines.

With dual interface flexibility, you can create automated API tests visually or switch to code mode. Tests can be managed in suites, reused across projects, and integrated with collaboration platforms like Slack and JIRA.

Katalon at a glance: 

Developer	Katalon, Inc.
Year launched	2015
Type of tool	All-in-one test automation platform
Top 3 use cases	API test automation, cross-platform UI testing, CI/CD integration
Who can use it	Testers (beginners & advanced), developers, DevOps engineers
AI capabilities	AI-assisted test creation, auto-healing for test scripts
Platform accessibility	Windows, macOS, Linux (desktop app) + Cloud (TestOps)

Key features:

• Fast test creation: Record-and-playback for beginners, extendable with code for experts.
• Comprehensive test coverage: Supports API, web, mobile, and desktop testing in one place.
• Flexible test execution: Run tests on multiple environments, locally or via CLI, with detailed reporting.
• API test automation: Send SOAP, REST, GraphQL requests, configure headers/params/bodies, and switch between no-code and code.
• Data-driven & BDD testing: Connect to XLS, CSV, or databases, and write BDD tests using Cucumber/Gherkin.
• Integrations: Works with Jenkins, GitLab, Azure DevOps, JIRA, Slack, Teams, and more.
• Reusable test assets: Import from Swagger, WSDL, Postman; reuse test artifacts across projects.
• Community & learning: 80,000+ members, 50+ free training courses.

What I liked about Katalon:

• Beginner-friendly, but powerful enough for advanced testers.
• Truly all-in-one (API + UI + mobile + desktop); fewer tools to juggle.
• Rich integration ecosystem with DevOps and CI/CD pipelines.
• Detailed dashboards and analytics in Katalon TestOps.

What I didn’t like about Katalon: 

• Resource-intensive on large projects; can slow down.
• Limited free plan – many advanced features locked behind a paywall.
• Steeper learning curve if you dive into scripting too quickly. 

Ideal user/use case

Katalon is ideal if you want a single platform that can handle both API testing and broader test automation (web, mobile, desktop). It’s best suited for teams that want scalability, strong CI/CD integration, and collaboration-friendly test management.

Pricing

Plan	Free	Create	Expand	Scale
Price	$0 (Free forever)	From $84/user/month (annual plan)	From $168/user/month (annual plan)	Custom pricing (Talk to sales)
Best for	Individuals and small teams just starting with automation	Teams creating and maintaining automated tests	Teams needing advanced execution in any environment	Enterprises with advanced security & deployment needs
Support	Community support & docs	24/5 support	24/5 support	24/5 support + dedicated agent

4. SoapUI [Best for enterprise-grade SOAP and REST API testing]

SoapUI is one of the most established API testing tools, created by SmartBear. It comes in two flavors: the open-source SoapUI (focused on functional API testing) and the commercial ReadyAPI (which adds advanced capabilities like load testing, security testing, and analytics). SoapUI is especially strong in SOAP-based web service testing, while also supporting REST and GraphQL APIs.

How it works

With SoapUI, you can import WSDLs, Swagger, RAML, or Postman collections, then create automated functional, regression, or load tests. The tool allows both drag-and-drop test creation (great for beginners) and custom scripting in Groovy/JavaScript (great for advanced users). It also supports mocking services so you can test APIs even if they’re not live yet.

SoapUI at a glance: 

Developer	SmartBear Software
Year launched	2005
Type of tool	API testing tool (functional + load + security)
Top 3 use cases	SOAP testing, REST/GraphQL testing, security/load testing
Who can use it	QA engineers, developers, and enterprise test teams
AI capabilities	None (manual/script-based automation)
Platform accessibility	Windows, macOS, Linux (desktop app)

Key features:

• Protocol support: SOAP, REST, GraphQL, JMS, JDBC, AMF, and more.
• Drag-and-drop test creation: Build complex tests without heavy coding.
• Scripting support: Extend automation with Groovy/JavaScript scripts.
• Assertions and parameterization: Validate responses, pass dynamic data.
• Data-driven testing: Integrate external sources like Excel or databases.
• Security testing: Detect vulnerabilities like SQL injection or XML threats.
• Load and performance testing: Simulate multiple users hitting your API.
• Mock services: Create simulated services for isolated testing.
• Import/export support: Bring in definitions from WSDL, Swagger, RAML, and Postman.
• Reports and analytics: Generate detailed insights into test runs.

What I liked about SoapUI:

• Open-source option covers most basic functional API testing.
• Extremely powerful for SOAP services (still relevant in enterprise).
• Broader coverage than Postman – especially with load and security testing.
• Supports scripting and reusable test cases for complex environments.

What I didn’t like about SoapUI: 

• Outdated UI; not very intuitive compared to modern tools.
• Can get slow and resource-heavy with large/complex tests.
• No history tracking of past executions (unlike Postman).
• Some advanced features are locked in the commercial (ReadyAPI) version.

Ideal user/use case

SoapUI is ideal for enterprise teams handling SOAP and REST APIs that require advanced functionality, including load testing, security checks, and service mocking. If you’re working in a complex enterprise environment with legacy SOAP services, SoapUI will likely serve you better than Postman.

Pricing 

SoapUI is a free, open-source tool. 

5. JMeter [Best for performance and load testing]

Apache JMeter is an open-source, Java-based load and performance testing tool. Originally built for testing web applications, it has grown into a versatile platform for testing APIs, databases, FTP servers, and even mail servers. 

JMeter works by simulating multiple users (via “Thread Groups”) and sending requests to servers to measure performance, response times, and stability under various loads. Its plugin ecosystem, reporting capabilities, and CI/CD integration make it a staple in QA and DevOps workflows.

How it works

To run API tests in JMeter, you build a Test Plan, the backbone of your testing setup. This includes:

• Adding a Thread Group to simulate the number of users and request frequency.
• Configuring an HTTP Request with API endpoint details (server, method, path, headers, and parameters).
• Applying Assertions to validate response accuracy.
• Running the plan to observe response times, throughput, and error rates through listeners.

More complex scenarios can be set up with multiple thread groups, distributed testing across machines, and plugins for CI/CD integration. 

JMeter at a glance: 

Developer	Apache Software Foundation
Year launched	1998
Type of tool	Open-source load and performance testing tool
Top 3 use cases	Load testing APIs/web apps, stress testing servers, simulating multiple protocols
Who can use it	QA engineers, performance testers, DevOps teams
AI capabilities	None (manual scripting & plugins instead)
Platform accessibility	Cross-platform (Windows, macOS, Linux — any JVM-supported system)

Key features:

• Versatile load and performance testing: Supports HTTP/HTTPS, REST, SOAP, FTP, JDBC, LDAP, JMS, SMTP/POP3/IMAP, TCP, and more.
• Full-featured test IDE: Record, build, and debug Test Plans with an intuitive IDE.
• Command-Line Interface (CLI) mode: Run tests in headless mode on any Java-compatible OS.
• Dynamic HTML reports: Automatically generate rich, presentation-ready reports.
• Data extraction and correlation: Extract data from JSON, XML, and HTML responses for correlation.
• Multithreading framework: Simulate multiple users with concurrent sampling and thread groups.
• Distributed testing: Run coordinated tests across multiple machines to simulate heavy loads.
• Caching and offline analysis: Replay test results and analyze them without rerunning tests.
• Highly extensible: Extend with plugins, custom scripts (Groovy/Beanshell), and visualization add-ons.
• Continuous integration support: Integrates with Jenkins, Maven, Gradle, and other CI/CD tools.
• Java-based portability: Fully portable across OS platforms thanks to its Java foundation.
• Protocol-level operation: Operates at the protocol level, without rendering JavaScript or HTML like a browser.

What I liked about JMeter:

• Open-source and completely free.
• Wide protocol support (HTTP, SOAP, REST, FTP, JDBC, etc.).
• Generates detailed reports and data visualizations.
• Distributed testing allows for higher load simulations.
• Backed by a strong, active community with plenty of resources.

What I didn’t like about JMeter: 

• Steep learning curve for beginners unfamiliar with performance testing.
• Large-scale tests can consume significant system resources.
• Lacks browser-level testing (cannot simulate real front-end behavior like JavaScript execution).

Ideal user/use case

JMeter is ideal for QA teams, DevOps engineers, and developers who need to simulate real-world traffic and test system resilience under heavy loads. It’s best suited for projects where open-source flexibility, protocol-level testing, and CI/CD integration are key.

Pricing 

JMeter is 100% free and open-source.

6. ReadyAPI [Best for enterprise-grade API testing across functional, security, and performance]

ReadyAPI, developed by SmartBear, is a comprehensive low-code API testing platform designed for teams that need functional, security, and load testing in one place. Unlike lightweight tools such as Postman, ReadyAPI is enterprise-focused, enabling end-to-end API validation, service virtualization, and integration into CI/CD workflows. It supports REST, SOAP, GraphQL, WebSocket, and more, making it a versatile choice for large, complex API ecosystems.

How it works

Testing in ReadyAPI is built around projects. A typical workflow looks like this:

• Import or define your API using standards like OpenAPI/Swagger, WSDL, or AsyncAPI.
• Use the drag-and-drop interface to create functional tests, add assertions, and parameterize with real or mock data.
• Run security scans (SQL injection, fuzzing, vulnerabilities) or load tests against endpoints.
• Virtualize APIs to remove external dependencies during development.
• Integrate results with CI/CD pipelines and export reports for stakeholders.

Its mix of low-code simplicity and scripting support (Groovy, JavaScript) makes it accessible for testers but still flexible for developers. 

ReadyAPI at a glance: 

Developer	SmartBear
Year launched	2015 (as the commercial successor to SoapUI Pro)
Type of tool	Commercial low-code API testing suite
Top 3 use cases	Functional testing, security validation, performance/load testing
Who can use it	QA teams, developers, DevOps engineers, and enterprise IT teams
AI capabilities	None native, but integrates with automation frameworks
Platform accessibility	Windows, macOS, Linux

Key features:

• Low-code functional testing: Point-and-click interface for building and running data-driven API tests.
• Wide API protocol support: REST, SOAP, GraphQL, WebSocket, JMS, TCP, and MQTT.
• Assertions made easy: Add logic checks without writing code, or extend with Groovy/JavaScript when needed.
• Service virtualization: Mock REST, SOAP, TCP, or JMS services to remove external dependencies during testing.
• Continuous testing support: Seamless integrations with Jenkins, TeamCity, GitHub, Azure DevOps, and more.
• Comprehensive reporting: Export results as JUnit-style reports, HTML dashboards, or CSV.
• Security testing suite: Built-in scans for vulnerabilities and penetration testing.
• Performance/load testing: Scale test execution to simulate thousands of concurrent API requests.
• CI/CD ready: Works natively with DevOps pipelines.
• Collaboration-friendly: Project sharing, version control, and team management features.

What I liked about ReadyAPI:

• Low-code approach makes building complex tests quick and accessible.
• Robust protocol support, including legacy SOAP and modern GraphQL/MQTT.
• Backed by SmartBear with excellent documentation, training, and community support.
• Service virtualization eliminates bottlenecks in dependent systems.
• Clean, intuitive interface suitable for both testers and developers.
• Seamless CI/CD integrations for enterprise workflows. 

What I didn’t like about ReadyAPI: 

• Commercial tool with a steep licensing cost compared to open-source options.
• Running large-scale load tests can be resource-heavy.
• Learning curve for advanced features, especially if migrating from Postman.
• Overkill for small teams or simple API testing needs.

Ideal user/use case

Best suited for enterprise DevOps teams and QA departments managing large-scale API ecosystems where functional correctness, performance, and security testing all need to happen in a unified workflow. Especially valuable when multiple protocols or service virtualization are required.

Pricing 

Module	Price	Key features
API Test Module	Starting at €1,000/license	Scriptless and custom scripting Data-driven testing Multi-protocol support Automated test assertions
API Performance Module	Starting at €7,299/license	Flexible load generation Parallel API load tests Server monitoringPre-built load templates
API Virtualization Module	Starting at €1,399/license	Simple virtual service creation Share and deploy virtual services Manage and generate mock data Simulate Server-Side Behavior

7. RapidAPI for Mac (formerly Paw) [Best for macOS-native API development and testing]

RapidAPI for Mac (formerly Paw) is a dedicated macOS application built specifically for API testing and development. Unlike cross-platform tools, it feels like a native Mac app with a sleek design and seamless integration into the macOS environment. The platform helps developers and testers make HTTP requests, debug APIs, generate client code, and document workflows in an intuitive, visually engaging way.

Another standout aspect of this tool is its collaborative approach. Teams can share projects, mock APIs, and get real-time updates on changes, making it especially useful when multiple stakeholders are working together on the same API project.

How it works

At its core, RapidAI for Mac acts as a powerful HTTP client. You can send requests, view responses, and organize everything neatly into projects. It supports complex authentication methods, JSON schemas, and scripting through extensions, while also providing real-time mock servers for simulating APIs. Once set up, RapidAI for Mac automatically generates documentation and client code in multiple languages, streamlining the development pipeline.

RapidAI for Mac at a glance: 

Developer	Paw Cloud (later acquired by RapidAPI)
Year launched	2013
Type of tool	Native macOS API client and testing tool
Top 3 use cases	API testing, client code generation, and collaborative API documentation
Who can use it	macOS developers, testers, API architects, and technical teams
AI capabilities	No built-in AI features (relies on scripting and plugins)
Platform accessibility	macOS only

Key features:

• macOS-native design: RapidAI for Mac is fully optimized for macOS, offering smooth performance and system-level integrations.
• Visual editor: Provides a full-featured, intuitive visual editor for crafting and organizing HTTP requests.
• Comprehensive protocol support: Works with REST, SOAP, GraphQL, WebSocket, and supports JSON schemas.
• Authentication methods: Includes OAuth 1.0, OAuth 2.0, Basic Auth, Digest, and custom headers.
• Mock server: Built-in mock server to simulate APIs before actual deployment.
• Code generation: Exports client code snippets in multiple languages, like Objective-C, Swift, JavaScript, and others.
• Auto documentation: Automatically generates and updates API documentation from your requests.

What I liked about RapidAI for Mac:

• Feels like a true macOS app: fast, sleek, and intuitive.
• Excellent for code generation across different programming languages.
• Team collaboration features are seamless and easy to adopt.
• Built-in mock server is a big plus for early testing and prototyping.
• Great for organizing complex API projects visually.

What I didn’t like about RapidAI for Mac: 

• Limited only to macOS users; no Windows or Linux support.
• Doesn’t have native AI-driven features, unlike newer tools.
• It can feel pricey compared to free or cross-platform alternatives.
• Slight learning curve if you’re transitioning from Postman.

Ideal user/use case

It’s ideal for developers and teams who are fully embedded in the macOS ecosystem. If you value a polished UI, want to generate client code in Swift or Objective-C, or need to collaborate on API testing with teammates in real time, Paw is a strong fit. However, if your workflow spans Windows or Linux, it may not be the best option.

Pricing 

It’s free for personal and professional use. 

8. LoadNinja [Best for codeless API and load testing]

LoadNinja, developed by SmartBear, is a cloud-based load and performance testing tool that also supports API testing. Unlike traditional scripting-based tools, LoadNinja takes a codeless approach, using record-and-playback features to let testers build tests without writing code.

It allows teams to simulate thousands of real browser sessions across devices and locations, identify bottlenecks, and validate how web apps or APIs behave under load. With its machine learning assistant, LoadNinja can even detect anomalies automatically, making test analysis faster and smarter.

In short, LoadNinja saves time by removing scripting complexity while delivering enterprise-level performance insights.

How it works

LoadNinja uses a browser-based, scriptless recorder (InstaPlay) that enables testers to create and run performance or API scenarios within minutes. It simulates traffic from different geographies, browsers, and devices, capturing metrics like navigation timings, transactions per second, and response times.

Because it runs on the cloud, there’s no need for infrastructure setup. Testers can launch large-scale load tests instantly. Results come with real-time dashboards, plus AI-driven anomaly detection for deeper insights.

LoadNinja at a glance: 

Developer	SmartBear
Year launched	2018
Type of tool	Cloud-based load & performance testing with API test support
Top 3 use cases	API performance testing, load testing for web apps, anomaly detection
Who can use it	QA engineers, developers, DevOps teams, performance testers
AI capabilities	Machine learning assistant for anomaly detection; AI-powered InstaPlay
Platform accessibility	Web-based (cloud), integrates with CI/CD pipelines

Key features:

• InstaPlay recorder: AI-powered record-and-play tool to create web and API tests quickly without coding.
• TrueLoad technology: Simulates real browser traffic at scale, offering accurate load conditions.
• Real-time performance analysis: Provides actionable insights with metrics like response time, navigation timings, and transactions per second.
• Seamless integrations: Works with CI/CD pipelines (Jenkins, GitLab, Zephyr Squad, etc.) via REST API.
• Wide protocol support: Supports REST, SOAP, GraphQL, and WebSocket APIs.

What I liked about LoadNinja:

• Cuts down test creation and management time with its codeless, scriptless interface.
• Combines API and load testing in one tool without needing third-party integrations.
• Advanced, real-time reporting makes identifying performance bottlenecks easier.

What I didn’t like about LoadNinja: 

• Primarily designed as a load testing tool, API testing features feel secondary.
• Doesn’t support all API protocols as comprehensively as specialized API tools.
• May have a learning curve for testers new to performance testing. 

Ideal user/use case

LoadNinja is ideal for QA teams, DevOps engineers, and developers who need to test how their APIs and web applications perform under realistic load but don’t want to spend time writing scripts. It’s best for teams prioritizing speed, scalability, and integrated performance analysis.

Pricing 

Plan	Best for	Price	Key features
Professional	Lighter traffic testing	$350/25 load testing hours	Test up to 500 Virtual UsersAdd unlimited team members
Enterprise	Moderate to high traffic testing	Custom	Plans start at 25 hoursTest any number of Virtual Users Add unlimited team members

9. Assertible [Best for Continuous API Testing in CI/CD]

Assertible is a cloud-based automated API testing and monitoring tool that helps developers and QA teams ensure their APIs remain functional, secure, and reliable across environments. It’s designed for continuous testing, making it an excellent fit for CI/CD pipelines. As a Postman alternative, Assertible offers advanced features like JSON Schema validation, assertion chaining, and parameterized testing for broader test coverage.

How it works

Assertible continuously runs automated API tests against your environments (staging, production, or custom), syncing with your API specifications and executing checks after every deployment. It integrates into CI/CD workflows, monitors webhooks, and provides real-time alerts when issues arise. Teams can collaborate easily through integrations with GitHub, Slack, Zapier, and PagerDuty.

Assertible at a glance: 

Developer	Assertible Inc.
Year launched	2015
Type of tool	Cloud-based automated API testing and monitoring tool
Top 3 use cases	Automating API regression testing in CI/CD pipelines; continuous monitoring of APIs in staging and production environments; and debugging and validating API responses with assertions and schema checks
Who can use it	Developers, QA engineers, DevOps teams, product managers
AI capabilities	None (primarily automation-driven, not AI-driven)
Platform accessibility	Web-based platform (cloud), works across browsers and integrates with external services via APIs and webhooks

Key features:

• Automated API testing: Schedule, run, and monitor API tests automatically.
• Custom assertions: Define and chain assertions for detailed response validation.
• CI/CD integration: Automate tests within pipelines (Jenkins, Travis CI, GitHub Actions, etc.).
• Webhook support: Validate webhooks with automated triggers and monitoring.
• Team collaboration: Share test suites, results, and reports with your team.
• Detailed reporting & analytics: Track uptime, performance, and reliability with real-time dashboards.
• Specification sync: Automatically update tests as API specs (OpenAPI, Postman collections, Swagger) evolve.
• Real-time alerts: Get notified via Slack, email, or SMS when tests fail.

What I liked about Assertible:

• Very easy to set up, install, and get running.
• Real-time failure alerts can be customized for the entire team.
• Saves hours of manual testing with automated regression checks.
• Excellent GitHub, Slack, and Zapier integrations for smooth workflows.

What I didn’t like about Assertible: 

• Primarily focused on API testing, it lacks features for other types of testing.
• May not be the best fit for highly complex or enterprise-level testing scenarios.
• Limited AI-driven enhancements compared to newer tools.

Ideal user/use case

Assertible is best suited for developers, DevOps engineers, and QA testers who need continuous, automated API testing in CI/CD pipelines without heavy setup. It’s ideal for agile teams that deploy frequently and need quick validation of staging and production APIs.

Pricing 

Plan	Price	Best for	Key features
Personal (FREE)	$0	Individuals testing APIs with full automation & monitoring tools	2 web services10 tests per service1,000 result retention1-2 membersStandard schedule frequency
Standard	$25/month	Developers needing enhanced monitoring & higher retention	25 web services500 tests per service5,000 result retention1 memberUpgraded schedule frequency
Startup	$50/month	Small teams collaborating on API testing & monitoring	25 web services500 tests per service5,000 result retention10 membersUpgraded schedule frequency
Business	$100/month	Larger organizations building robust QA/testing pipelines	50 web services1000 tests per service10,000 result retention20 membersUpgraded schedule frequency

10. Karate Labs [Best for versatile API + UI testing in one framework]

Karate Labs is an open-source test automation platform that unifies API testing, performance testing, API mocks, and even UI testing, all under one roof. Its strength lies in its simplicity. You can write tests in plain, Gherkin-based syntax, making it approachable even for non-programmers.

Instead of juggling multiple tools, Karate Labs lets teams create end-to-end automated workflows, from sending API requests to validating response data, simulating environments, and even performance testing. For those who prefer not to work directly with Java, Karate offers a cross-platform standalone executable.

Karate generates HTML-based reports by default, so you get a clear breakdown of request/response data, test steps, and failures, making debugging and reporting straightforward.

How it works

Karate Labs uses a domain-specific language (DSL) built on Gherkin syntax, allowing you to describe tests in natural language. You can test SOAP, REST, and GraphQL APIs, define test data in JSON or CSV, and even set up mocks. Tests can be run in parallel, integrated with CI/CD pipelines, and extended with custom Java code where needed.

Karate Lab at a glance: 

Developer	Karate Labs (Community-driven, originally by Intuit)
Year launched	2017
Type of tool	Open-source test automation framework
Top 3 use cases	API automation, performance testing, UI automation
Who can use it	Developers, QA testers, non-programmers (low learning curve)
AI capabilities	None (focuses on automation, not AI)
Platform accessibility	Cross-platform (standalone executable + Java-based support)

Key features:

• Gherkin-based syntax: Write tests in plain language, making it beginner-friendly.
  Support for multiple APIs: Test RESTful, SOAP, and GraphQL APIs in one framework.
• Built-in assertions and reporting: Get detailed HTML reports with assertions out of the box.
• Data-driven testing: Run tests with JSON, CSV, or external data inputs.
• Mocks and stubs: Simulate APIs and services during development.
• Performance testing: Built-in capabilities for load and performance checks.
• Parallel execution: Run multiple test cases simultaneously for better coverage.
• Extensible with Java: Add custom scripts and integrations where needed.
• CI/CD integration: Seamlessly plug into Jenkins, GitHub Actions, and other pipelines.

What I liked about Karate Lab:

• Easy for beginners thanks to natural language syntax.
• Parallel test execution improves efficiency.
• Reuse test cases across projects to save time.
• Comprehensive reports that are easy to read.

What I didn’t like about Karate Lab: 

• Primarily focused on APIs and UI; not suitable for every kind of testing.
• There’s a learning curve if you want advanced features (Java knowledge helps). 

Ideal user/use case

Karate Labs is ideal for teams that want an all-in-one open-source testing solution covering API, performance, and UI testing without juggling multiple tools. It’s beneficial for QA teams that need collaboration-friendly, low-code testing options but also want the flexibility to extend with Java for complex scenarios.

Pricing 

Karate offers multiple pricing tiers starting with an Open-Source plan (free) that includes core features like API testing, performance testing, mocks, browser automation, and CI/CD integrations. 

The Xplorer freemium plan adds no-code local setup, API chaining, and flow management. A paid upgrade ($200/user/year) unlocks advanced support for importing from OpenAPI, Swagger, and Postman. 

The PLUS plan ($100/year) builds on Free with syntax support, code formatting, reporting, and remote environments. 

Finally, the PRO plan ($640/year) includes advanced debugging, enhanced IDE features, autocomplete, JSON tools, and premium integrations such as Kafka, gRPC, WebSocket, and Webhook. A runtime license is required for CI/CD, with additional enterprise pricing available on request.

Questions to ask before choosing a Postman alternative

• Does it integrate smoothly with CI/CD and improve workflows?
• Can it handle complex, high-load scenarios?
• Does it cover all your testing needs (API, performance, mocks, etc.)?
• What’s the pricing model? Are there hidden costs?
• Does it meet compliance and security standards?
• Does it enhance collaboration instead of creating silos?
• Will you get reliable support?

If a vendor falls short on any of these, they may not be the right fit.

The tools highlighted above, including Hoppscotch, Katalon, Apache JMeter, Insomnia, LoadNinja, and Assertible, serve different needs depending on your team’s skills, budget, and testing requirements.

Best practices for API testing and monitoring

If there’s one thing I’ve learned while looking at these API testing tools, it’s that having the right tool is only half the story. The other half is knowing how to use it effectively. Whether you’re team Postman or one of the alternatives we’ve explored, these best practices will help you get the most out of your API testing and monitoring setup.

1. Start with clear test objectives

Don’t just run tests for the sake of it. Define what you’re testing (e.g., functionality, performance, security, or reliability) and align those goals with your business needs. A test without purpose is just noise.

2. Cover both positive and negative scenarios

It’s easy to test happy paths, but don’t forget the messy edges. APIs need to gracefully handle invalid inputs, missing fields, and unexpected payloads. Negative testing ensures your system doesn’t crumble when real-world users (or bad actors) send junk.

3. Use data-driven testing

Automate tests with different sets of input data (JSON, CSV, or even databases). This helps you validate multiple scenarios without rewriting test cases, ensuring broader coverage with less effort.

4. Automate early and integrate with CI/CD

API tests should run automatically every time new code is pushed. Continuous testing ensures bugs are caught before they sneak into production. Integration with CI/CD tools like Jenkins, GitLab CI, or GitHub Actions makes testing part of the workflow, not an afterthought.

5. Monitor APIs in real time

Testing before release is not enough. APIs can break due to dependency changes, traffic spikes, or third-party failures. Set up real-time monitoring with alerts so you know before users do.

6. Focus on performance under load

Your API may work fine with 10 users, but what happens with 10,000? Use load and stress testing to check how your system behaves under pressure. Identify bottlenecks and scale accordingly.

7. Prioritize security testing

APIs are a favorite target for attackers. Test for vulnerabilities like SQL injection, authentication flaws, data leaks, and insecure endpoints. Regularly validate compliance with standards like OWASP API Security Top 10.

8. Document and report results clearly

Detailed test reports aren’t just for QA engineers. They help developers, product managers, and stakeholders understand the system’s health. Look for tools that provide HTML dashboards or exportable reports with request/response details.

9. Simulate real-world environments

Don’t just test in perfect lab conditions. Simulate different environments; low bandwidth, high latency, or multiple geographies to see how APIs behave for actual users.

10. Keep collaboration in mind

API testing isn’t a one-person job. Utilize platforms that enable sharing of test cases, results, and dashboards across teams. This breaks down silos and helps developers, QA, and ops stay on the same page.

Conclusion

Testing and monitoring APIs is the backbone of reliable digital products. While Postman has been a trusted favorite for years, the market is full of capable alternatives, such as Katalon, Karate, and others, each offering unique strengths that depend on your workflow, team size, and testing needs.

The real key is asking the right questions, adopting best practices, and choosing a tool that integrates seamlessly into your CI/CD pipeline while supporting collaboration, scalability, and security. APIs don’t live in isolation; they power everything from mobile apps to cloud platforms, so ensuring they run smoothly is non-negotiable.

At the end of the day, the best Postman alternative isn’t necessarily the most popular one, but the one that fits your team’s goals, handles your edge cases, and scales with your growth. Pick wisely, test often, and keep monitoring; your future self (and your users) will thank you.

FAQs about Postman alternatives for API testing 

1. Which Postman alternative is completely free for teams? 

Karate Labs and Insomnia are fully open-source and free to use. They offer core features without forcing teams into paid plans, making them great choices for small to mid-sized teams on a budget.

2. Can I import my Postman collections easily?

Yes. Most major alternatives, including Hoppscotch, Insomnia, and Katalon, support importing Postman collections in JSON format. This makes migration smoother without requiring the rebuilding of tests from scratch.

3. Which tool integrates best with VS Code?

Hoppscotch stands out here. It offers tight integration for developers who prefer a browser-based experience linked to their workflow.

4. What’s the best CLI-based alternative?

Newman (Postman’s own CLI tool) remains strong, but if you’re looking beyond that, HTTPie CLI and cURL are popular for developers who want speed, simplicity, and shell scripting power.

5. Which one handles large collections fastest?

Tools like Katalon Studio and ReadyAPI are better suited for heavy workloads and complex test suites. They’re optimized for large collections, parallel execution, and enterprise-scale performance testing.

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This publication, review, or article (“Content”) is based on our independent evaluation and is subjective, reflecting our opinions, which may differ from others’ perspectives or experiences. We do not guarantee the accuracy or completeness of the Content and disclaim responsibility for any errors or omissions it may contain.

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