REST APIs allow software systems to exchange data using standard HTTP methods. Choosing the right REST API tool makes testing, debugging, and managing APIs faster and more reliable.
Overview
What Is a REST API?
A REST API (Representational State Transfer Application Programming Interface) is a way for software systems to communicate over the web using standard HTTP methods. It defines how clients send requests to a server and how the server responds, usually in a structured format like JSON or XML.
Why Use a REST API Tool?
Using a REST API tool improves efficiency, accuracy, and collaboration across development and testing teams.
- Simplified Testing: Send requests and review responses without repetitive coding.
- Automation Support: Run automated test suites and monitor APIs consistently.
- Debugging Assistance: Identify and fix errors in API responses quickly.
- Scenario Simulation: Modify requests or responses in real-time to test edge cases.
- Team Collaboration: Share requests, workflows, and insights across team members.
Best REST API Tools in 2025
Here is a quick overview of the top REST API tools for 2025:
- Requestly: Modify HTTP requests and responses in real-time, test APIs without backend changes, and simulate advanced scenarios.
- Postman: Build, test, and monitor APIs with automation and detailed response inspection.
- Insomnia: Manage REST and GraphQL APIs with environment support and request chaining.
- SoapUI: Perform functional, regression, and load testing for REST and SOAP APIs using scripting.
- HTTPie: Command-line tool for sending HTTP requests with readable output and quick debugging.
- Assertible: Automate API testing, validate responses, and monitor uptime with minimal setup.
- Swagger: Design, document, and generate client SDKs in a unified platform.
This article explains the types of REST API tools, their key features, and how to choose the right one for testing and development workflows.
What Is a REST API Tool?
A REST API tool is a software application that helps developers and testers work with REST APIs more efficiently. These tools allow users to send HTTP requests, inspect responses, automate tests, and simulate complex API scenarios without manually writing repetitive code.
They provide a structured environment to interact with APIs, making it easier to develop, test, and debug applications.
Here are the core capabilities of a REST API tool:
- Request Management: Send GET, POST, PUT, DELETE, and other HTTP requests without writing custom scripts.
Read More: HTTP Methods: GET vs POST vs PUSH
- Response Inspection: View detailed response data, including status codes, headers, and body content.
- Automation Testing: Set up test suites, run repeated tests, and schedule monitoring tasks.
- Scenario Simulation: Modify HTTP requests or responses in real-time to test edge cases and complex workflows.
Also Read: Life Cycle of an HTTP Request
- Collaboration: Share request collections, test results, and environment setups across teams.
Why Use a REST API Tool?
APIs are central to modern applications, and testing them manually can quickly become impractical. A REST API tool does more than simplify requests and responses. It provides insights, control, and reliability across the entire API lifecycle.
Here is why REST API tools are essential:
- Structured Testing Across Environments: You can manage multiple environments, such as development, staging, and production, with consistent configurations. This ensures tests run reliably regardless of where they are executed.
- Data Validation and Consistency Checks: The tools automatically validate API responses against expected schemas or business rules. This helps catch subtle data inconsistencies that could break production systems.
- Advanced Workflow Simulation: You can chain multiple API requests, modify headers, and simulate conditional responses. This allows replication of real-world scenarios and testing of edge cases.
- Performance and Reliability Insights: REST API tools allow monitoring of response times, detection of bottlenecks, and assessment of API stability under load without manual benchmarking.
- Error Diagnosis and Root Cause Analysis: Detailed request and response logs, status codes, and headers help pinpoint the exact source of failures, reducing debugging time.
- Collaboration and Governance: You can share collections, automated tests, and environment setups across teams. This ensures consistent testing standards and faster onboarding of new developers.
- Continuous Integration and DevOps Integration: API tests can be integrated into CI/CD pipelines. This prevents regressions and ensures new releases do not break existing functionality.
Read More: How to build an effective CI CD pipeline
Key Types of REST API Tools
REST API tools serve different purposes depending on their primary focus in the API lifecycle. Each type addresses specific challenges and provides features tailored to different stages of API work.
Below are the main types of REST API tools, explained in detail:
1. REST API Clients
REST API clients allow users to send HTTP requests and view responses interactively. They provide features such as environment management, authentication handling, parameterization, and request chaining. These clients are ideal for exploratory testing, debugging, and validating API endpoints. They help teams understand API behavior quickly without writing additional code.
Read More: Best REST API Client Tools for 2025
2. API Testing Tools
API testing tools focus on automating the validation of API functionality. They support functional testing to check individual endpoints, regression testing to ensure new changes do not break existing functionality, and performance testing to measure response times under load.
These tools often include assertions, test suites, and scripting capabilities, enabling repeatable and scalable testing workflows.
3. API Design and Documentation Tools
These tools help define and maintain API specifications. They provide schema validation, interactive documentation, visual editors, and SDK generation. API design tools ensure consistent standards, improve collaboration between developers and testers, and make it easier for clients to consume APIs reliably.
4. API Lifecycle and Management Platforms
Lifecycle platforms manage APIs from development to retirement. They include features for monitoring, security, versioning, analytics, and policy enforcement. These platforms help organizations maintain control over APIs, enforce governance, and monitor usage for optimization. They are particularly valuable when multiple APIs need to be maintained across distributed systems.
Popular REST API Tools in 2025
Here are 7 best REST API tools in 2025. Compare the features and pros and cons to choose the best solution for your requirements.
1. Requestly by BrowserStack
Requestly is a versatile REST API tool that allows developers and testers to intercept, modify, and debug HTTP requests and responses in real-time. It is designed to simulate complex API scenarios without changing the backend, making it useful for testing, debugging, and validating workflows efficiently.
Key Features of Requestly
- API Playground: Interactive environment to test API endpoints, modify requests, and inspect responses without affecting the backend.
- API Collections: Organize related API requests into collections for structured testing and repeatable workflows.
- Local & Team Workspaces: Work individually or collaboratively with consistent configurations, environment variables, and rules.
- API Tests: Create automated tests with assertions to validate responses, status codes, headers, and payloads.
- Import from Postman & Bruno: Quickly import existing API requests, collections, and tests to reduce setup time and maintain familiar workflows.
Why Choose Requestly?
Requestly empowers developers and testers to efficiently simulate and debug API interactions without backend dependencies. By enabling real-time request interception and modification, it accelerates development cycles and enhances testing accuracy.
Furthermore, Requestly’s simple setup and clear interface reduce the time spent configuring and running tests. Teams can quickly simulate requests, debug responses, and validate scenarios, which accelerates API testing and reduces errors.
Pricing
- Free: $0
- Lite: $8/month
- Basic: $15/month
- Professional: $23/month
2. Postman
Postman is a REST API client that enables developers and testers to send requests, inspect responses, and organize workflows across multiple environments. It supports automation, collaboration, and integrations with common development tools.
Key Features of Postman
- Request Builder: Send GET, POST, PUT, DELETE, and other HTTP requests with configurable headers and parameters.
- Collections: Group related API requests for reuse and organized workflows.
- Automated Testing: Validate responses and status codes with assertions and test scripts.
- Environment Management: Maintain consistent configurations across different environments.
Pros and Cons of Postman
| Pros | Cons |
|---|---|
| Intuitive interface suitable for beginners and experienced users | Can be heavy and resource-intensive for large projects |
| Strong automation and testing capabilities | Advanced features require paid plans |
| Collaboration support through shared workspaces | Managing complex scripts and environments has a learning curve |
3. Insomnia
Insomnia is a REST and GraphQL API client designed for developers and testers to send requests, inspect responses, and manage environments efficiently. It supports scripting, request chaining, and collaboration through workspace management.
Key Features of Insomnia
- Request Builder: Send HTTP requests with customizable headers, parameters, and payloads.
- Environment Management: Manage multiple environments and variables for consistent testing.
- Request Chaining: Execute dependent requests in sequence to simulate workflows.
- Scripting and Automation: Add scripts to test responses and automate repetitive tasks.
Pros and Cons of Insomnia
| Pros | Cons |
|---|---|
| Lightweight and fast compared to other API clients | Limited collaboration features in free version |
| Supports REST and GraphQL APIs in a single interface | Fewer integrations with external tools than some competitors |
| Clean and simple UI makes request management straightforward | Advanced automation requires learning scripting |
4. SoapUI
SoapUI is a functional testing tool for both REST and SOAP APIs, used to validate API behavior, performance, and security. It supports automated testing and complex workflows.
Key Features of SoapUI
- Functional Testing: Validate API endpoints with assertions and scripted test cases.
- Load Testing: Measure API performance under varying load conditions.
- Mock Services: Simulate API endpoints for testing without live backend services.
- Automation and Scripting: Use Groovy scripts to automate tests and handle complex scenarios.
Pros and Cons of SoapUI
| Pros | Cons |
|---|---|
| Supports both REST and SOAP APIs | Interface can feel outdated and complex |
| Powerful automation and scripting options | Steeper learning curve for beginners |
| Mock services allow testing without backend | Can be resource-heavy on large test suites |
5. HTTPie
HTTPie is a command-line HTTP client that simplifies sending requests, debugging APIs, and inspecting responses. It is designed for speed and clarity in CLI environments.
Key Features of HTTPie
- Command-Line Requests: Send GET, POST, PUT, DELETE requests from the terminal.
- Readable Output: Format responses with syntax highlighting for easy inspection.
- JSON Support: Automatically formats and parses JSON requests and responses.
- Authentication: Supports multiple authentication schemes like OAuth and basic auth.
Pros and Cons of HTTPie
| Pros | Cons |
|---|---|
| Lightweight and fast for CLI users | Lacks GUI, which can be challenging for beginners |
| Clear, formatted output for easy debugging | Limited automation capabilities compared to GUI tools |
| Supports complex requests with minimal syntax | Requires familiarity with command-line operations |
6. Assertible
Assertible is an API testing and monitoring platform designed to validate API reliability, monitor uptime, and automate test runs.
Key Features of Assertible
- Automated Testing: Validate API responses and run tests on schedules.
- Monitoring: Track API uptime, response times, and status codes over time.
- Assertions: Create rules to validate payload structure, headers, and response content.
- Integration: Connect with CI/CD pipelines for automated validation during deployments.
Pros and Cons of Assertible
| Pros | Cons |
|---|---|
| Simplifies monitoring and validation of APIs | Limited advanced scripting options |
| Integrates with CI/CD pipelines for automation | GUI may be restrictive for complex workflows |
| Easy setup for scheduled tests | Smaller feature set than full-fledged API testing platforms |
7. Swagger
Swagger is an API design and documentation tool that helps teams create, maintain, and share API specifications. It supports schema validation and SDK generation.
Key Features of Swagger
- API Design: Define API endpoints, parameters, and request/response schemas visually.
- Interactive Documentation: Generate and share interactive API documentation for easy consumption.
- Mock Servers: Simulate API responses without a live backend.
- SDK Generation: Generate client SDKs for multiple programming languages from API specifications.
Pros and Cons of Swagger
| Pros | Cons |
|---|---|
| Improves API documentation clarity and accessibility | Focused mainly on design and documentation, not testing |
| Supports mocking to test without live backend | Less suitable for deep automated testing workflows |
| SDK generation saves development effort | Limited collaboration features compared to dedicated testing platforms |
How to Choose a REST API Tool
Selecting the right REST API tool depends on the specific needs of a project, the complexity of the APIs, and the workflows of the team. Choosing carefully ensures efficient testing, reduces errors, and improves collaboration.
Below are key considerations for evaluating REST API tools:
- Purpose and Scope: Identify whether the primary need is exploratory testing, automated validation, API design, or lifecycle management. Tools designed for testing may not provide robust documentation features, and vice versa.
- Ease of Use and Learning Curve: Assess how quickly team members can get started. A tool with an intuitive interface and clear workflow reduces onboarding time and prevents configuration errors.
- Automation Capabilities: Consider whether the tool supports automated tests, assertions, and integration with CI/CD pipelines. Automation is essential for regression testing, repeated validation, and ensuring API reliability.
- Environment and Workspace Management: Evaluate how the tool handles multiple environments, variables, and team collaboration. Proper environment management ensures consistent testing across different stages of development.
Read More: Test Environment: A Beginner’s Guide
- Integration and Extensibility: Check for compatibility with existing development and monitoring tools, version control systems, and scripting support. Integration allows seamless workflows and better observability.
- Performance and Resource Usage: Assess whether the tool performs efficiently under large workloads and multiple requests. Lightweight tools can save time and reduce system resource constraints.
Conclusion
REST API tools are essential for developers and testers to validate, debug, and optimize API workflows efficiently. Each tool offers unique capabilities, from interactive request testing to automated validation, performance monitoring, and documentation.
Choosing the right tool depends on project needs, workflow complexity, and collaboration requirements. Tools like Requestly provide real-time request and response modification, automated testing, and workspace management, while others focus on testing, monitoring, or documentation.
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