Best Self-hosted API Development, Mocking & Testing tools in 2026

Hoppscotch Community Edition is an open-source API development and testing tool for REST, GraphQL, WebSocket, SSE, MQTT, and Socket.IO with collections and environments.

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Postman+9

Kong Gateway is a high-performance, cloud-native API gateway for routing, securing, and observing API traffic, with an extensible plugin system and Kubernetes support.

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Amazon API Gateway+7

A Python-based notification library and CLI that routes messages to 120+ services via URL-based configurations, enabling self-hosted cross-platform alerts.

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Twilio+4

Maxun is an open source no-code platform to build web scraping robots that extract structured data and expose websites as APIs, markdown, or automated pipelines.

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Apify+1

LibreTranslate is a free, open-source machine translation API you can run on your own infrastructure, with offline-capable translations and a simple HTTP API.

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Google Translate

FlareSolverr is a proxy server with a REST API that uses a headless Chrome session to solve Cloudflare/DDoS-GUARD challenges and return HTML and cookies.

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Browserless+7

Gotenberg is a containerized HTTP API that converts HTML, Markdown, and Office documents to PDF using engines like Chromium and LibreOffice, with options to merge and aut...

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PDFShift+9

OmniTools is a self-hosted web app providing browser-based utilities for images, video, PDF, text, date/time, math, and data formats, with client-side processing.

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iLovePDF+7

Lura is a stateless, high-performance API gateway framework for building reverse proxies that aggregate, transform, and secure backend APIs via middleware and plugins.

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Amazon API Gateway+9

Open-source API client and HTTP interceptor to test APIs, modify requests and responses, and create API mocks for faster development and debugging.

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Postman+10

Scraperr is a self-hosted web scraping app with a web UI, XPath extraction, job queueing, domain spidering, media downloads, and CSV/Markdown export.

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Apify+3

Open-Meteo is an open-source weather API providing hourly forecasts, historical weather, air quality and more from national weather models, with optional self-hosting.

Browser-based whiteboard that doubles as a cloud development environment with terminals and in-browser editor.

Judge0 CE is an open-source, sandboxed online code execution system with an HTTP JSON API for running untrusted code in many programming languages at scale.

Svix is an open-source webhook service that handles event ingestion, signing, retries, and endpoint management with scalable delivery and client libraries.

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Svix+6

Open-source API gateway for securing, aggregating, and transforming microservice APIs with a stateless, high-throughput Go-based runtime and declarative configuration.

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Amazon API Gateway+7

SQLPage is a fast SQL-only web app builder that turns .sql files into interactive web pages and APIs on top of your existing database.

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Retool+19

Open-source form and data management platform with a drag-and-drop builder, embeddable form renderer, and REST API for submissions, resources, and workflows.

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Formstack+12

Self-hosted web application to track and manage 3D-printing filament spools with a REST API, WebSocket updates, label/QR printing and integrations for common printer fron...

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SimplyPrint+6

Fusio is an open source API management platform for building, securing, and operating REST APIs, with a web backend, developer portal, and SDK generation.

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Amazon API Gateway+5

Yaade is a self-hosted, collaborative API development environment that lets teams share API collections, run tests, and import from OpenAPI or Postman.

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Postman+10

Lightweight open-source feature flag system with a relay proxy, OpenFeature support, file/cloud retrievers, and exporters for usage data.

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Unleash+4

OpenRouteService is an open-source REST API providing routing, isochrones, matrices, geocoding, POIs, elevation and vehicle-optimization services built from OpenStreetMap...

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NextBillion.ai Directions API

DreamFactory generates secure, documented REST APIs for SQL/NoSQL databases and other services, with a web admin UI, authentication, and role-based access control.

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Hasura+7

Graphweaver turns multiple databases and APIs into a single, code-first GraphQL API with an extensible admin UI and fine-grained access control.

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Hasura+10

Python library to manage RSS/Atom/JSON feeds with read-state, tagging, filtering, and full-text search.

Express middleware that generates REST collection APIs from JSON Schema with a Django-like admin UI; supports MongoDB, PostgreSQL or JSON-file storage.

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Directus Cloud+10

Capture, inspect and debug webhooks and HTTP requests with customizable responses, real-time WebSocket UI, and memory/Redis/filesystem storage options.

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Webhook.site+2

Privacy-first string toolkit with 50+ converters and formatters for developers.

Self-hosted HTTP API to render web pages to PNG with configurable viewport, caching, Playwright-based parallel rendering, and S3/CouchDB/filesystem storage.

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Urlbox+4