# rest-api

Email API service that gives AI agents their own inboxes and identities

AgentMail is a YC S25 startup that provides email infrastructure specifically designed for AI agents. It gives each agent its own email address and inbox, enabling agents to send, receive, and manage email conversations independently. With $6 million in seed funding from General Catalyst and Paul Graham, and over 500 B2B customers, AgentMail solves the identity and communication gap that arises when organizations deploy autonomous agents that need to interact via email.

Batteries-included full-stack framework for React, Node.js, and Prisma

Wasp is an open-source full-stack web framework that brings the Rails-like batteries-included experience to the JavaScript ecosystem. It uses a declarative configuration file to define auth, database models, server operations, and routing, then compiles to a standard React and Node.js application with Prisma for data access. With 18,000+ GitHub stars and YC backing, Wasp eliminates boilerplate while giving AI coding agents clear structure and guardrails.

AI-native API gateway by Alibaba with MCP server hosting and LLM routing

Higress is an open-source AI-native API gateway developed by Alibaba that combines traditional API management with LLM-specific capabilities like token-based rate limiting, model routing, prompt caching, and MCP server hosting. Built on Envoy and Istio, it provides enterprise-grade traffic management while natively understanding AI workload patterns including streaming responses, long-lived connections, and multi-model fallback chains.

Open-source financial data platform for quants, analysts, and AI agents

OpenBB is an open-source financial data platform that normalizes data from 100+ providers into a unified Python SDK, REST API, and Excel Add-in. It serves as the open-source alternative to Bloomberg Terminal for developers building fintech applications, quantitative research pipelines, and AI-powered financial analysis tools. With over 65,000 GitHub stars and SOC 2 Type II certification, it is one of the most popular open-source developer tools for financial data.

Multi-model database for the AI era — document, graph, vector, and relational in one

SurrealDB is a multi-model database that natively combines document, graph, relational, key-value, and vector storage in a single engine. It eliminates the need for separate databases by handling structured queries, graph traversals, full-text search, and vector similarity in one SQL-like query language called SurrealQL. Built in Rust for performance and safety, it supports real-time subscriptions, row-level permissions, and embedded or distributed deployment modes.

Cost-effective AI inference platform with 86+ models from $0.02/M tokens

DeepInfra is an AI inference platform offering 86+ LLM models with pricing starting at $0.02 per million tokens. Backed by $20.6M in funding including an $18M Series A from Felicis Ventures, it provides OpenAI-compatible endpoints for models including DeepSeek, Llama, and Mistral with pay-as-you-go pricing.

Zero-config conversion of FastAPI endpoints into MCP tools

FastAPI-MCP automatically converts existing FastAPI endpoints into Model Context Protocol tools with zero configuration. With 11,700+ GitHub stars, it is the most popular MCP integration layer, enabling thousands of FastAPI developers to make their APIs accessible to AI agents like Cursor and Claude through the MCP standard.

World's largest API hub and marketplace

RapidAPI is the world's largest API hub and marketplace connecting developers to thousands of public and private APIs through a single platform. Provides a unified interface for discovering, testing, and managing API connections with standardized authentication, billing, and monitoring. Features an API testing playground, code snippets in multiple languages, team workspaces, and analytics dashboards. Used by millions of developers to integrate third-party services with a single API key.

Open-source API client

GLM-based AI coding subscription offering access to advanced reasoning models for code generation and development tasks. Provides competitive token pricing with flexible usage tiers. Compatible with OpenAI-compatible endpoints and popular coding agents like Claude Code and Cursor, making it easy to integrate into existing AI-assisted development workflows.

Human-friendly HTTP client

User-friendly CLI HTTP client for testing and debugging APIs with intuitive syntax, colorized output, and JSON highlighting. Simpler than curl with sensible defaults — auto JSON formatting, persistent sessions, and auth helpers. Also available as HTTPie Desktop (GUI) and HTTPie for Web (browser-based). Supports HTTPS, proxies, file uploads, and plugins. 34K+ GitHub stars. The developer-friendly curl alternative for API work.

Git-friendly offline API client

Open-source API client for testing REST, GraphQL, and gRPC APIs as a lightweight, privacy-focused alternative to Postman. Stores API collections as plain files in your Git repository for easy version control and team collaboration. Features environment variables, scripting, collection runner, and a declarative syntax called Bru. Offline-first with no cloud account required. Available on macOS, Windows, and Linux. 29K+ GitHub stars and growing rapidly among developers leaving Postman.

Open-source API client

Open-source API client by Kong for designing, debugging, and testing REST, GraphQL, gRPC, and WebSocket APIs. Features a clean interface with environment variables, authentication helpers, code generation, cookie management, and response timeline. Supports OpenAPI and Swagger specs for design-first workflows. Git Sync for version-controlled API collections. Available on macOS, Windows, and Linux. A popular alternative to Postman with stronger focus on privacy and local-first usage.

API development and testing platform

The most popular API platform used by 30M+ developers worldwide. Build, test, and document APIs with collections, environments, automated testing, and team collaboration. Features mock servers, monitoring, API design tools, and a vast public API network. The industry standard for API development workflows from prototyping through production testing and documentation.

OpenAPI-powered developer portals

OpenAPI documentation renderer with a clean three-panel layout that generates beautiful, responsive API reference pages from your OpenAPI spec. Available as open-source React component or CLI-generated static site. Supports code samples in multiple languages, search, and deep linking, making it the go-to choice for teams who want polished API docs without custom development.

API for GPT-4, o1, DALL-E, Whisper, and embeddings

Official API platform for GPT-4o, o1/o3 reasoning models, DALL-E image generation, Whisper speech-to-text, and text embeddings. Features Assistants API, function calling, JSON mode, fine-tuning, and batch processing. The most widely used AI API in the industry, powering millions of applications from chatbots to complex multi-step agent systems across every sector.

Direct API access to Claude models with tool use

Official API for Claude models including Opus, Sonnet, and Haiku. Supports tool use, computer use, extended thinking, and batch processing. Features prompt caching, streaming, and Messages API with vision capabilities. Known for strong performance on complex reasoning tasks, nuanced instruction following, and safety-conscious design that makes it trusted for enterprise and production applications.

Google Cloud ML platform with Gemini and custom models

Google Cloud's end-to-end ML platform with Gemini models, Model Garden featuring 150+ models, AutoML, and custom training pipelines. Features Vertex AI Search, Conversation, and Agent Builder for enterprise AI applications. The comprehensive platform for organizations building production AI systems at scale within the Google Cloud ecosystem, with enterprise governance and compliance built in.

OpenAI models with Azure enterprise security

AWS managed ML platform providing the full machine learning lifecycle from data preparation through model deployment and monitoring. Includes SageMaker Studio IDE, JumpStart model hub, and built-in MLOps features. The dominant ML platform for enterprises already invested in AWS, offering deep integration with the broader AWS service ecosystem for end-to-end AI workflows.

Managed foundation models on AWS

Microsoft's cloud AI platform offering Azure OpenAI Service for GPT and DALL-E models with enterprise security, compliance, and regional data residency. Includes AI Studio for model catalog, fine-tuning, and prompt engineering. The default AI platform for Microsoft-centric enterprises that need access to frontier models with the governance and compliance guarantees Azure provides.

Enterprise AI for text generation, search, and RAG

Open-source deployment platform for machine learning models. Package models as standard containers, serve via REST/gRPC APIs, and scale across GPU clusters. Supports all major ML frameworks including PyTorch, TensorFlow, and Hugging Face Transformers. The standard for teams who need reproducible, scalable model serving without vendor lock-in or proprietary infrastructure dependencies.

The GitHub of ML — model hub, datasets, and inference

Open-source platform for building, sharing, and deploying machine learning models and datasets. Hosts 500k+ models, 100k+ datasets, and Spaces for interactive demos. The central hub of the open-source AI ecosystem, providing model discovery, inference APIs, and collaborative tools that make it the GitHub of machine learning for researchers and developers worldwide.

Run and deploy ML models via API with simple pricing

Unified API gateway that provides access to hundreds of LLM models from OpenAI, Anthropic, Google, Meta, and open-source providers through a single OpenAI-compatible interface. Features model fallbacks, price comparison, and community-driven model rankings. The most popular LLM routing service for developers who want multi-provider flexibility without managing individual API integrations.

Production-grade inference with serverless and on-demand GPUs

Open-source model serving platform optimized for large language models and generative AI. Supports Hugging Face models, LoRA adapters, and continuous batching for efficient multi-user serving. Built on PyTorch with OpenAI-compatible endpoints. Designed for teams who need production-grade LLM serving with lower latency and better resource utilization than generic model serving frameworks.

Ultra-fast LPU inference with fastest token generation

Enterprise AI platform for fine-tuning and deploying custom language models. Offers Command R family of models, Embed API for retrieval, and Rerank API for search relevance. Known for strong enterprise features including data privacy guarantees, custom model training, and retrieval-augmented generation capabilities that help organizations build AI applications grounded in their proprietary data.