Compare 39+ free API development tools — Postman, Hoppscotch, Insomnia, Bruno, Mintlify, Swagger, RapidAPI, Nango, and more. Exact free tier limits. Verified July to September 2026.
The API development toolchain has fragmented into dozens of specialized free tools. Hoppscotch is a fully open-source (MIT) Postman alternative with REST, GraphQL, WebSocket, and MQTT support. Bruno stores API collections as files in Git — no cloud sync needed. Insomnia offers local-first API design and testing. And Mintlify generates beautiful API docs from OpenAPI specs with a free tier.
This page compares 41 free API development tools — from API testing clients and GraphQL platforms to mocking services, documentation tools, API marketplaces, and integration platforms. Cross-reference with our Postman alternatives guide for deeper Postman-specific comparisons.
Recent API Tool Pricing Changes
Postman: Free plan now single-user only. Team collaboration (shared workspaces, collection sharing) requires paid plan at $19/... Source ↗
SwaggerHub: Free community plan replaced by trial only Source ↗
Postman: The free tier now includes 50 AI credits and has limitations on API monitoring requests (1,000 requests/month). Team ... Source ↗
Mintlify: The 'Hobby' tier is no longer available. The lowest tier is now 'Starter' at $0/month. Includes 5 editor seats, a web... Source ↗
API design, debugging, testing, and documentation platform — free tier: up to 4 users, unlimited projects, unlimited APIs, unlimited requests. API mocking included. 7-day change history
Free OSS (MIT). Git-based offline API client — REST, GraphQL, collections stored as files in your repo. No cloud, no accounts, no sync. Desktop app for Mac/Linux/Windows. The #1 open-source Postman alternative
Lightweight REST API client for VS Code and JetBrains. Free plan is $0 per user/month with local storage and 1 local collection run per month. Paid plans are billed annually from Starter at $3 per user/month, which adds JetBrains, team features, CLI and CI/CD, WebSocket/SSE/gRPC and 250 collection runs; Business is $7 and Enterprise $16.
GraphQL federation and supergraph platform — forever free: up to 3 users, 1-day data retention, self-hosted router (60 req/min rate limit), community support. No credit card required
Open-source API client for designing and testing REST, GraphQL, gRPC, WebSocket, and SSE APIs. Local-first with Git sync and optional cloud storage. No account required for local testing. Desktop app for Mac/Linux/Windows. Free tier includes unlimited projects and collection runner
Post HTTP Requests Online. Popular Request Methods include GET, POST, PUT, DELETE, and HEAD. Supports Headers and Token Authentication. Includes a basic login system for saving your requests.
Tools for designing OpenAPI specs, generating documentation, and building developer portals. From visual API designers to full documentation platforms.
API design and documentation platform (SmartBear) — no permanent free tier. Swagger's own pricing FAQ, read 2026-09-05: "You can get started with Swagger with a free trial, no credit card required, then choose the plan that best fits your usage and requirements." The same FAQ puts the free Swagger tools on the open-source side — Swagger Editor, Swagger UI and Swagger Codegen, run locally — and SwaggerHub among the commercial products. Plan prices are client-rendered and were not read.
Superseded: As of 2026-08-28, tiny.cloud reads: The Free Plan includes 1,000 editor loads per month and TinyMCE core editing features. A 14-day free trial of 21 + advanced features is also available. We are not publishing our stored TinyMCE terms beside it — our own pricing change record, discovered 2026-08-28, names them as the previous ones. Read what we recorded ↓
Collaborative design API with instant API mock and generated documentation (Free for unlimited API blueprints and unlimited users with one admin account and hosted documentation).
Quickly auto-generate models/class/type/interface and serializers from JSON, schema, and GraphQL for working with data quickly & safely in any programming language. Convert JSON into gorgeous, typesafe code in any language.
Mock API servers, fake data generators, and request inspection tools. Essential for frontend development, integration testing, and prototyping without a real backend.
No-code, cloud-based platform for mocking and debugging multi-protocol APIs (REST, SOAP, gRPC & GraphQL), providing instant servers with rules-based logic, CRUD & stateful mocking, proxying, and CORS management for faster integration and testing. The free plan includes 50 requests per day and provides a public dashboard/endpoint where anyone with the dashboard URL can view submitted requests and responses.
MockAPI is a simple tool that lets you quickly mock up APIs, generate custom data, and perform operations using a RESTful interface. MockAPI is meant to be a prototyping/testing/learning tool. One project/2 resources per project for free.
Free mock REST API service providing realistic data across 9 domains (e-commerce, finance, healthcare, education, recruitment, social media, stock markets, weather, and aviation). No mandatory signup, no API keys, unlimited requests. Perfect for frontend prototyping, API testing, learning and teaching web development.
Mockfly is a trusted development tool for API mocking and feature flag management. Quickly generate and control mock APIs with an intuitive interface. The free tier offers 500 requests per day.
Create a free endpoint to which you can send HTTP requests. Any HTTP requests sent to that endpoint will be recorded with the associated payload and headers so you can observe recommendations from webhooks and other services.
Superseded: As of 2026-09-01, mockaroo.com reads: Mockaroo lets you generate up to 1,000 rows of realistic test data...Need more data? Plans start at just $60/year. We are not publishing our stored mockaroo terms beside it — our own pricing change record, discovered 2026-09-01, names them as the previous ones. Read what we recorded ↓
Superseded: As of 2026-09-01, mocklets.com reads: Basic Free per user / month Includes: 1 Collection 10 Apis / Collection 5 Files / Collection 2 Members / Collection. We are not publishing our stored Mocklets terms beside it — our own pricing change record, discovered 2026-09-01, names them as the previous ones. Read what we recorded ↓
Platforms offering curated collections of third-party APIs — from geolocation and email validation to product data and exchange rates. Most offer generous free tiers per API.
API marketplace hosting 90+ data APIs (exchangeratesapi, ipstack, mediastack, etc.). Most APIs include a free tier with 100-1,000 requests/month. Individual API pricing varies by provider
API marketplace and hub — free to sign up and browse. Individual APIs set own free tiers (typically 500-1K req/mo). Platform rate limits: 1,000 req/hr, 500K req/mo. No platform fee on free API tiers
Get instant access to over 120+ APIs for free, built with quality, consistency, and reliability in mind. The free plan covers up to 50 API Tokens per month. (Possibly taken down, 2025-06-25)
Platforms for connecting APIs together, managing webhooks, monitoring API usage, and building integration pipelines. These handle the plumbing between your services.
Superseded: As of 2026-08-28, nango.dev/pricing reads: The Free plan is $0/mo and includes 10 connections, 100k proxy requests, 10 hours of function compute time, 100k function runs, 100k custom function logs, 100k custom sync storage records, and 100k API webhooks. We are not publishing our stored Nango terms beside it — our own pricing change record, discovered 2026-08-28, names them as the previous ones. Read what we recorded ↓
Hook0 is an open-source Webhooks-as-a-service (WaaS) that makes it easy for online products to provide webhooks. Dispatch up to 100 events/day with seven days of history retention for free.
Developer-focused PDF generation API designed with privacy in mind. It offers Stripe-inspired documentation and includes 500 free PDF conversions per month.
Create secure RESTful APIs from CSV files. Upload a CSV file and instantly access the data via its API allowing faster application development. The free plan includes 2 APIs and 2,500 API calls per month. You don't need a credit card.
Treblle helps teams build, ship, and govern APIs. With advanced API log aggregation, observability, docs, and debugging. You get all features for free, but there is a limit of up to 250k requests per month on the free tier.
Amazon Selling Partner API for building seller and vendor tools on Amazon. Sellers/vendors using SP-API for their own business remain fully exempt (free). Third-party developers: $1,400/year annual fee active since Jan 31 2026; Basic tier includes 2.5M GET calls/month. Per-call overage fees ($0.40 per 1K GET calls) were scheduled for 2026-04-30 but postponed indefinitely after developer backlash — no new date announced.
Product data management API for Google Merchant Center. Being sunset August 18, 2026 — replaced by Merchant API (rolling out April 22, 2026). Free to use with a Google Merchant Center account. Provided product listing, inventory management, and order management endpoints. Developers must migrate to Merchant API before the sunset date.
Free and open-source desktop app for creating local API mocks — dynamic responses, request logging, record/replay and OpenAPI import. Mockoon Cloud adds hosted mocks and collaboration: Team is $100/month billed annually for 5 members, 3 deployed mocks and 100,000 calls/month, with a 14-day trial on a work email (7 days and a card otherwise).
Automatically generate RESTful API documentation with Swagger 2.0 for Go. Annotate your handler functions, run swag init, and get a Swagger UI endpoint; works with chi, gin, echo, fiber and net/http. Free and MIT-licensed, with optional sponsorship through Open Collective.
Hoppscotch and Bruno lead the open-source API client space — both MIT-licensed with no vendor lock-in. Postman remains the industry standard with the largest ecosystem. For GraphQL, Apollo GraphOS handles federation while Hasura generates instant APIs. Mintlify is the top choice for modern API docs. Verified July to September 2026.
Which Free API Tool Should I Use?
Need a free Postman alternative?
Hoppscotch — fully open-source (MIT) with REST, GraphQL, WebSocket, SSE, Socket.IO, and MQTT support. Self-hostable. See our Postman alternatives guide for a deeper comparison.
Want Git-native API collections?
Bruno — stores collections as files on your filesystem, version-controllable in Git. No cloud account needed. MIT licensed.
Need an all-in-one API design + test + docs platform?
Apidog — free for up to 4 users with unlimited APIs, combining API design, debugging, testing, mocking, and documentation in one tool.
Building beautiful API documentation?
Mintlify — free tier includes custom domain, web editor, and API playground. Stoplight for OpenAPI visual design. SwaggerHub for Swagger/OpenAPI hosting.
Need instant GraphQL APIs?
Hasura — generates a GraphQL API over any database instantly. Hasura DDN Free plan: unlimited API requests and unlimited concurrent users (1 supergraph developer, 15-min observability retention). Apollo GraphOS for GraphQL federation and supergraph management.
Need mock APIs for frontend development?
Beeceptor — no-code mock APIs for REST, SOAP, and GraphQL. MockAPI for quick REST mocking with custom data. mockaroo for realistic test data generation.
Looking for third-party data APIs?
RapidAPI — largest API marketplace with thousands of APIs. AbstractAPI for geolocation, email validation, and utility APIs. API Ninjas for 100+ free REST APIs.
Need to connect multiple APIs together?
Nango — integration infrastructure for 600+ APIs with unified auth and data syncing, 10 connections free. Treblle for API observability and governance.
Looking for more? Browse all API Development tools or search across all 1,547 tools in the AgentDeals index.
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