Open Source API Tools
Discover 179 open source API repositories from GitHub, each with an analysis of what it does, key features, use cases and alternatives. API projects here are most often combined with Self Hosted, Python and TypeScript. Last updated October 4, 2026.
179 repositories · updated October 4, 2026
heyoo: Connect Python Apps to WhatsApp Cloud API
heyoo is an unofficial Python wrapper for WhatsApp Cloud API, covering message sending and webhook payload handling. It suits Python developers building WhatsApp messaging or support workflows who want a library-level interface instead of assembling API requests themselves.
wa-js: Access WhatsApp Web Functions from JavaScript
WA-JS exports WhatsApp Web functions through a JavaScript global API for browser-based integrations and automation. It suits developers building chat, group, business, or account workflows that run in WhatsApp Web.
waha-net: Use the WAHA WhatsApp API from .NET
A C# client library for integrating WAHA, the WhatsApp HTTP API, into .NET applications. Use it to connect to WAHA sessions and retrieve chat data through a .NET-friendly client.
dnyHelpRealm: Manage Customer Support Tickets
dnyHelpRealm is a PHP helpdesk for freelancers and small teams to receive and manage customer support requests by email, web forms, and API. It supports ticket routing, agent workflows, and email-based replies.
dss: Create and Validate Electronic Signatures
DSS is a Java framework for creating, extending, and validating advanced electronic signatures. It supports common signature formats and is aimed at developers building signature workflows that need standards-based processing.
bigcapital: Manage Business Accounting and Inventory
Bigcapital is a self-hostable accounting and inventory application for small and medium businesses. It uses double-entry accounting to organize transactions and produce financial statements and reports.
traccar: Track GPS Devices and Vehicles
Traccar is a Java-based GPS tracking server for vehicles, assets, and people. Self-host it to manage device locations, alerts, and reports, or use its REST API to integrate tracking with other systems.
apprise: Send Notifications Across Many Services
Apprise is a Python library and CLI for sending alerts through a shared interface to a wide range of notification services. It suits developers and administrators who want one integration for apps, scripts, and infrastructure.
imgproxy: Resize and Convert Images on Demand
imgproxy is a standalone HTTP server that resizes, transforms, and converts images when requested. It suits teams that want to move image processing out of their application and serve optimized images through a URL-based API.
cli: Send and Inspect HTTP Requests from the Terminal
HTTPie CLI is a Python command-line client for sending HTTP requests with readable syntax and formatted output. It is useful for testing APIs, debugging services, and making repeatable requests from scripts or a terminal.
fastapi: Build APIs with Python type hints
FastAPI is a Python web framework for building HTTP APIs from standard type annotations. It validates and converts request data and generates OpenAPI documentation, making it a fit for teams that want typed API development with interactive docs.