18.4
Scalar is a collection of API products for documentation, client generation, API management, requests, and MCP server use.
Free planOpen sourceWebAPILinux
Best API Development Tools in 2026
Use API development tools to design APIs, handle specification formats, test requests, build mock servers and get deployments ready. This category also covers version-control needs and tools that run through an API or on hosted systems. Compare the platforms before you choose. Check for an Android app if you work from a Xiaomi, Redmi or POCO phone or tablet, then check web, Windows, macOS, Linux or self-hosted…
28.3
HTTPie is an API client for building and testing requests to APIs, HTTP servers, and web services.
Free planOpen sourceWebLinuxmacOS
38.2
SoapUI is an open-source tool for testing REST, SOAP and GraphQL web services.
Free planOpen sourceAPILinuxmacOS
- 4
Bruno
Bruno is a Git-native API client for exploring and testing REST, GraphQL, gRPC, and WebSocket APIs.
Free planOpen sourceAPIExtensionLinuxmacOS8.1From $6 a month - 5
Apidog
Apidog is an API platform for designing, debugging, mocking, testing, and documenting APIs, with GraphQL and SOAP support.
Free planWebAPIExtensionLinux8.0From $9 a month - 6
Beeceptor
Beeceptor is a developer-focused API simulation platform for creating mocks, virtualizing services, testing contracts, and simulating failures.
Free planWebAPILinuxmacOS7.9From $10 a month - 7
Testfully
Testfully is an API testing and monitoring platform with web, desktop and browser extension options.
Free planWebExtensionLinuxmacOS7.8Free plan - 8
Postman
Postman is a platform for designing, testing, distributing, documenting, and monitoring APIs.
Free planWebExtensionLinuxmacOS7.6From $9 a month - 9
ReadyAPI
WebAPILinuxmacOS7.6 - 10
Pact
Pact is a code-first tool for contract testing of HTTP and message integrations.
Free planAPILinuxmacOSSelf-hosted7.5From $115.42 a month - 11
Insomnia
Insomnia is an API collaboration platform for designing, testing, debugging, mocking, and governing APIs.
Free planLinuxmacOSSelf-hostedWindows7.2From $12 a month - 12
Kreya
Kreya is a desktop API client for exploring, testing, and automating API workflows.
Free planLinuxmacOSWindows7.1Free plan - 13
SwaggerHub
SwaggerHub is a toolkit for API design, testing, documentation, and governance.
Free planWebSelf-hosted7.1From $740 a year - 14
HTTP Toolkit
HTTP Toolkit is an open-source tool for debugging, testing, and building with HTTP.
Free planAndroidiOSWebLinux7.0Free plan - 15
Redocly
WebAPIExtension7.0From $10 a month - 16
Requestly
Requestly is a desktop API client with web access for building, organizing, documenting, and testing APIs.
LinuxmacOSWindows7.0From $10 a month - 17
Thunder Client
Thunder Client is a REST API client that runs inside VS Code and JetBrains IDEs.
Free planExtensionLinuxmacOSWindows7.0From $3 a month - 18
Yaak
Yaak is a local-first desktop API client for sending requests, debugging APIs, and organizing work with Git.
Free planLinuxmacOSWindows7.0From $79 a year - 19
Assertible
Assertible tests and monitors APIs, websites, and other HTTP services for uptime, availability, and correct behavior.
Free planWebAPI6.9From $25 a month - 20
Mockoon
Mockoon is a free, open-source tool for designing and running mock APIs locally.
WebAPILinuxmacOS6.8From €10 a month - 21
ReadMe
Free planWeb6.7From $250 a month - 22
OpenAPI Generator
OpenAPI Generator creates API clients, server stubs, and documentation from OpenAPI 2.0 and 3.x documents.
Free planWebLinuxmacOSSelf-hosted6.5Free plan - 23
Bump.sh
Bump.sh is a paid web, API, and self-hosted service for publishing API documentation and providing MCP servers that update with API releases.
WebAPISelf-hosted6.4From $50 a month - 24
Schemathesis
Schemathesis generates property-based tests from OpenAPI and GraphQL schemas to help engineers find API bugs.
Free planLinuxmacOSSelf-hostedWindows6.4Free plan - 25
Stainless
Stainless generates SDKs, documentation, and MCP servers from OpenAPI specifications.
Free planWebLinuxmacOS6.4Free plan
Choosing well
Check where it runs
Look for tools running on Linux, macOS, Windows, the web, self-hosted setups or through an API. Confirm the exact setup you need, including whether an Android app is available for your phone or tablet.
Compare free and paid access
Check whether each tool offers a free plan or trial, then review its starting price, billing interval and trial duration before signing up.
Match your API workflow
Look at API design, testing and specification-format support. If you need simulated endpoints, check for mock-server support.
Plan for team delivery
How a tool handles deployment and version control may shape its fit with your workflow. Check whether its delivery model matches your project and whether open-source code matters for review or changes.
Questions people ask
Can I start without paying?
Check whether a tool offers a free plan or trial; terms differ by tool.
What platforms are covered?
This list includes Linux, macOS, Windows, web, self-hosted and API options. Confirm support for the platform you plan to use.
Which API features should I compare?
Review API design and testing, mock servers, specification formats, deployment and version-control support.
Is open-source code available?
Check whether the tool provides open-source code, then review its licence and project details before adopting it.