Free
Mockoon
Open SourceAPI Mocking · API Tools
Easy, open-source tool to run mock REST API servers locally.
mockingrestapiopen-source
Discover the 10 best free tools for api tools. Free-to-use, no credit card or subscription required. Curated, compared, and updated for developers.
| Tool | Pricing | Platforms | Top Strength | Link |
|---|---|---|---|---|
| Mockoon | free | desktop, cli | Easy, open-source tool to run mock REST API servers locally. | Details → |
| WireMock | free | cli, web | Flexible API mocking and service virtualization for HTTP. | Details → |
| JSONPlaceholder | free | web | Free fake REST API for prototyping and testing. | Details → |
| httpbin | free | web | HTTP request and response service for testing clients. | Details → |
| Auth.js | free | Web | Open-source authentication for Next.js and other JS frameworks. | Details → |
| Keycloak | free | Web | Open-source identity and access management with SSO and SAML. | Details → |
| OAuth.net | free | web | Official resource for the OAuth 2.0 authorization framework. | Details → |
| Zod | free | Web | TypeScript-first schema validation with static type inference. | Details → |
| Better Auth | free | Web | Framework-agnostic TypeScript authentication library (trending). | Details → |
| Mailpit | free | cli, web | Self-hosted email testing tool with a web UI, catches local mail. | Details → |
API Mocking · API Tools
Easy, open-source tool to run mock REST API servers locally.
API Mocking · API Tools
Flexible API mocking and service virtualization for HTTP.
API Mocking · API Tools
Free fake REST API for prototyping and testing.
API Mocking · API Tools
HTTP request and response service for testing clients.
Authentication · API Tools
Open-source authentication for Next.js and other JS frameworks.
Authentication · API Tools
Open-source identity and access management with SSO and SAML.
Authentication · API Tools
Official resource for the OAuth 2.0 authorization framework.
Authentication · API Tools
TypeScript-first schema validation with static type inference.
Authentication · API Tools
Framework-agnostic TypeScript authentication library (trending).
Email · API Tools
Self-hosted email testing tool with a web UI, catches local mail.