A curated list of high-quality APIs, SDKs, developer tools, open data sources, and API design resources to help developers build powerful applications across domains including AI, finance, mapping, social media, and more.
- Official API Design Resources
- API Clients & Frameworks
- AI & Machine Learning APIs
- Mapping, Geospatial & Location APIs
- Payments & Fintech APIs
- Communication & Messaging APIs
- Social Media APIs
- Open Data & Public APIs
- Monitoring, Testing & Security Tools
- Learning Resources
- Related Awesome Lists
- OpenAPI Specification – Standard for describing RESTful APIs in a language-agnostic format.
- AsyncAPI – Specification for describing event-driven and message-based APIs.
- JSON Schema – Vocabulary for validating and documenting JSON structures.
- GraphQL Spec – Official reference for building GraphQL APIs.
- gRPC – High-performance RPC framework for service communication.
- Postman – Popular platform for testing, documenting, and automating API workflows.
- Insomnia – API client for REST, GraphQL, and gRPC with powerful automation features.
- Swagger UI – Interactive documentation tool for OpenAPI specifications.
- Swagger Codegen – Tooling for generating API clients and server stubs.
- FastAPI – High-performance Python API framework with automatic OpenAPI docs.
- Express.js – Minimal Node.js framework for building REST APIs.
- NestJS – TypeScript framework for scalable enterprise API development.
- Hapi – Robust Node.js framework with built-in validation and API tooling.
- Flask – Lightweight Python framework ideal for small to mid-size APIs.
- Django REST Framework – Comprehensive toolkit for building powerful REST APIs in Django.
- OpenAI API – API for GPT models, embeddings, assistants, and multimodal intelligence.
- Anthropic Claude API – API for Claude models supporting natural language reasoning and analysis.
- Google Vertex AI – Unified ML platform offering training, prediction, and generative AI.
- AWS Bedrock – Foundation model API suite integrated with AWS services.
- Cohere API – NLP models for embeddings, RAG, generation, and semantic search.
- Hugging Face Inference API – Hosted inference for thousands of ML models.
- Replicate API – Cloud API for running open-source ML models at scale.
- AssemblyAI – Speech-to-text API with summarization, sentiment, and topic extraction.
- Google Maps Platform – Comprehensive mapping, geocoding, routing, and Places APIs.
- Mapbox – Developer-focused mapping platform with customizable maps and navigation tools.
- OpenStreetMap API – Open geospatial data for map and routing applications.
- Geoapify – Mapping and geocoding API built on open data sources.
- HERE Maps API – APIs for routing, traffic, geocoding, and fleet logistics.
- ArcGIS REST API – Enterprise-grade GIS tools for spatial analytics and maps.
- Stripe API – Payments, subscriptions, invoicing, and financial services via a modern developer API.
- PayPal / Braintree API – APIs for payments, billing agreements, and marketplace use cases.
- Plaid – API for banking connectivity, transactions, identity, and personal finance apps.
- Wise Platform – Cross-border transfers, FX rates, and multi-currency accounts.
- Coinbase Commerce – API for accepting cryptocurrency payments.
- Ramp API – Corporate spend management API for finance automation.
- Twilio – APIs for SMS, voice, chat, WhatsApp, verification, and communications.
- SendGrid – Email delivery and marketing automation with a flexible API.
- Mailgun – Transactional and bulk email API with strong deliverability tools.
- Vonage API – Communication APIs for SMS, voice, video, and authentication.
- Pusher – Real-time WebSocket API for multiplayer apps, notifications, and live features.
- X API (Twitter) – API for tweets, analytics, streaming, and real-time social data.
- Facebook Graph API – API for Facebook data, pages, ads, and insights.
- Instagram Graph API – Business-grade API for posts, analytics, and media insights.
- TikTok API – API for video posting, analytics, and audience insights.
- YouTube Data API – API for video metadata, channels, playlists, and analytics.
- Reddit API – Access to posts, comments, subreddits, and user interactions.
- LinkedIn API – API for profiles, jobs, ads, content, and analytics.
- NASA APIs – Public data and imagery for space exploration and research.
- NOAA API – Weather, climate, and environmental datasets via API.
- UN Data API – Global demographic, economic, and development data.
- World Bank API – Economic indicators and global development metrics.
- OpenWeatherMap – Weather forecasts, climate data, and sensor readings.
- REST Countries API – Country metadata for travel, education, and geographic applications.
- defend.network CVE API – Public API for CVE data, including CVSS, EPSS, and CISA KEV exploitation status.
- Public APIs List – Curated list of free APIs in multiple categories.
- OWASP API Security Top 10 – Official security guidance for API risk categories.
- API Fortress – API monitoring and automated QA for enterprise workflows.
- Hoppscotch – Lightweight open-source API testing client.
- Kong Gateway – API gateway for routing, authentication, and service discovery.
- Tyk API Gateway – Open-source API gateway with analytics and lifecycle management.
- Nginx API Gateway – High-performance gateway for API load balancing and security.
- Fixzi - Monitor API contracts and AI output schemas for breaking changes. Also includes JSON/XML validation, diff, and conversion tools.
- Postman Learning Center – Tutorials for designing, testing, and documenting APIs.
- Stripe Developers YouTube – API integration guides and live demos.
- Google Maps API Tutorials – Guides for geocoding, places, and navigation APIs.
- Designing APIs with OpenAPI – Practical guide for designing maintainable APIs.
- RESTful API Design Patterns – Concepts and patterns for building scalable REST services.
- gRPC Best Practices – Guidance for high-performance service architectures.
- API Design and Fundamentals – Industry-standard training on REST and OpenAPI.
- GraphQL Bootcamp – Practical course on designing GraphQL schemas and resolvers.
- FastAPI Mastery – Training for building modern Python APIs.
Contributions are welcome. Please ensure your submission fully follows the requirements outlined in CONTRIBUTING.md, including formatting, scope alignment, and category placement.
Pull requests that do not adhere to the contribution guidelines may be closed.
