API tools

• AiderAI pair programming in your terminal with any model

  Free / OSS · Apache-2.0 · 49.7k GitHub stars

  VerdictThe open-source terminal coding assistant for API-key purists.

  CatchYou are paying per-token at API rates—can exceed subscription costs on heavy use. No managed infrastructure; you are the ops team. Less polished than commercial alternatives.

• tRPCEnd-to-end typesafe APIs without codegen

  Free / OSS · OSS/MIT · 40.7k GitHub stars

  VerdictTypeScript APIs as they should be—type-safe by default.

  CatchTypeScript only—this is not for mixed-language teams. The tight coupling means you lose the API as a standalone artifact.

• FastAPIModern Python APIs at startup speed

  Free / OSS · OSS/MIT · 103k GitHub stars

  VerdictThe Python API framework you will actually enjoy.

  CatchThe ecosystem assumes you will integrate pieces yourself—no batteries-included ORM or auth. Async programming has its own learning curve.

• HTTPXAsync HTTP client for modern Python

  Free / OSS · BSD-3-Clause · 15.7k GitHub stars

  VerdictThe requests replacement for the async era.

  CatchAnother dependency when requests works for simple cases. Some requests plugins do not have HTTPX equivalents.

• SQLModelSQL + Pydantic in one elegant package

  Free / OSS · OSS/MIT · 18.4k GitHub stars

  VerdictOne model for database and API—elegant when it fits.

  CatchRelatively young library, so edge cases exist. Complex SQLAlchemy patterns may need direct SQLAlchemy access.

• LitestarThe FastAPI alternative with batteries

  Free / OSS · OSS/MIT · 8.5k GitHub stars

  VerdictMore opinionated FastAPI alternative worth considering.

  CatchSmaller community means fewer tutorials and Stack Overflow answers. Some FastAPI extensions need equivalents.

• GraphQL Code GeneratorType-safe Shopify API without manual typing

  Free / OSS · OSS/MIT · 11.3k GitHub stars

  VerdictEssential infrastructure for typed Shopify GraphQL.

  CatchConfiguration complexity for advanced setups. Build step adds friction to the workflow. Large schemas generate large type files.

• HonoTiny TypeScript web framework that runs on every runtime

  Free / OSS · OSS/MIT · 32.6k GitHub stars

  VerdictThe TypeScript HTTP framework when Next is the wrong shape.

  CatchNot Next.js. No filesystem router, no RSC, no batteries. You bring auth, ORM, and deploy. The Cloudflare-first energy is real — Node works, but the happy path is an edge runtime.

• Stripe CLIOfficial Stripe terminal for webhooks, events, and API objects

  Free / OSS · Apache-2.0 · 2.2k GitHub stars

  VerdictInstall it. Then still pay Stripe when money moves.

  CatchThe CLI is free; card charges are not. See stripe.com/pricing for processing rates. Live mode needs a real secret. Dispute fees are on Stripe, not on this binary.

• ntfyHTTP pub-sub notifications you can curl from cron

  Free / OSS · Apache-2.0 · 35k GitHub stars

  VerdictThe notification CLI that is actually free. curl it from a cron job.

  CatchAnonymous topics are passwords — guessable names leak other people's alerts. Public ntfy.sh rate-limits; reserved topics need Pro. Dual license means you pick Apache-2.0 or GPLv2, not Apache-only.

• OpenFGAApache-2.0 Zanzibar-style ReBAC with a Check API

  Free / OSS · Apache-2.0 · 6k GitHub stars

  VerdictApache-2.0 ReBAC. Self-host free. Not Cerbos YAML.

  CatchZanzibar-style ReBAC + Check API — not Cerbos YAML ABAC. Vs SpiceDB: CNCF/Okta OpenFGA modeling + Check API lane; SpiceDB is AuthZed production Zanzibar + ZedTokens/Cloud. Distinct from Cerbos.

• PostalMIT self-hosted mail delivery: SMTP + HTTP API

  Free / OSS · OSS/MIT · 16.9k GitHub stars

  VerdictMIT self-host mail. Free to run; deliverability is your ops.

  CatchSelf-hosted mail delivery SMTP+HTTP API — not Resend hosted tx email, not Plunk Node email, not Listmonk newsletter app. You own deliverability and IP reputation. Distinct from Resend, Plunk, and Listmonk.

• MailuMIT full mailbox stack: SMTP/IMAP/webmail — not tx API

  Free / OSS · OSS/MIT · 7.6k GitHub stars

  VerdictMIT mailbox suite. Free to run; ops-heavy vs a tx email API.

  CatchFull mailbox SMTP/IMAP/webmail — not Resend/Plunk/Postal transactional-or-relay API. Ops-heavy: DNS, TLS, spam, storage. Distinct from Postal, Plunk, and Resend.

• ElectricApache-2.0 Postgres read-path sync; Cloud PAYG under $5 waived

  Free / OSS · Freemium · 10.4k GitHub stars

  VerdictApache-2.0 Postgres sync. Self-host free; Cloud hobby under $5 waived.

  CatchRead-path sync — not a full offline-write CRDT stack or a replacement for your mutation API. Vs PowerSync/Replicache: Postgres-native shapes + free reads on Cloud, not mobile SQLite product packaging. Pro Cloud starts $249/mo.

• Paddle CLIMIT community CLI for full Paddle Billing API; agent-native

  Free / OSS · OSS/MIT · 1 GitHub stars

  VerdictMIT Paddle Billing CLI. Free tool; Paddle merchant + MoR fees separate.

  CatchCommunity CLI — not an official Paddle Inc product; API drift risk. Still need a Paddle merchant account (MoR fees apply). Vs Stripe CLI: Paddle-only. Thin MCP forks exist; this is the general CLI.

• SaleorBSD-3 GraphQL headless commerce; self-host free, Cloud from $1599/mo

  Free / OSS · Freemium · 23.5k GitHub stars

  VerdictBSD-3 headless commerce. Self-host free; Cloud production starts ~$1599/mo.

  CatchVs Shopify/Hydrogen: you own ops or pay Cloud. Production Cloud Select from about $1599/mo (to ~$200k GMV) / Volume ~$3999/mo — sandboxes are not for live selling. GraphQL-only + Django stack is a team bet. Not a Shopify App Store ecosystem.

• Uptime KumaMIT self-host uptime monitoring and status pages

  Free / OSS · OSS/MIT · 92.7k GitHub stars

  VerdictMIT self-host uptime. Free forever; you own the box on 3001.

  CatchSelf-host uptime + status pages — not Datadog/APM. You run the container, backups, and alerting path. HTTP/TCP checks are the lane, not full distributed tracing.

• PlaywrightApache-2.0 cross-browser library and CLI

  Free / OSS · Apache-2.0 · 98.2k GitHub stars

  VerdictApache-2.0 browser library. Free; MCP wrapper is a separate gem.

  CatchVs Playwright MCP gem: library/CLI lane; not the MCP wrapper. Heavier than unit tests. Browser downloads and CI images are real ops. Not Stagehand/Browserbase.

• ElysiaMIT ergonomic Bun-first web framework

  Free / OSS · OSS/MIT · 19.3k GitHub stars

  VerdictMIT Bun framework. Free forever; Hono is the multi-runtime cousin.

  CatchVs Hono: Bun-first ergonomic lane; Hono is multi-runtime edge-first. Ecosystem and hiring still Bun-skewed. Not Nest/Fastify full Node default.

• SuperGatewayMIT stdio↔SSE/WS bridge for MCP transports

  Free / OSS · OSS/MIT · 2.9k GitHub stars

  VerdictMIT MCP transport bridge. Wire stdio to remote clients; expect zero new capabilities.

  CatchPlumbing only — not a Playwright/Chrome DevTools MCP capability server. It does not add browser, docs, or symbol tools; it only rewires transport. If your client already speaks the server’s native transport, you do not need it.

• BrunoMIT git-native API client; Pro/Ultimate are optional seats

  Free / OSS · OSS/MIT · 47.8k GitHub stars

  VerdictMIT git-native API client. Free forever for local + CLI; pay only if the team wants the licensed desktop extras.

  CatchCore client is free forever; Pro (~$6/user/mo billed annually) and Ultimate (~$11) unlock in-app Git UI, OpenAPI sync quotas, and org admin. Golden Edition is sunset for new buys. Not a mock/monitor platform like Postman Cloud. Hoppscotch is the web-first alternative.

• zoxideMIT smarter cd — frecent directory jumper for every shell

  Free / OSS · OSS/MIT · 40.2k GitHub stars

  VerdictMIT frecent cd. Free forever when your muscle memory is folders, not full paths.

  CatchDirectory jumper only — not a file manager (Yazi), not a shell, not Atuin history. Needs a one-line shell init. Ranking learns from you; fresh machines feel empty until you walk around.

• HoppscotchMIT web-first open-source API client ecosystem

  Free / OSS · OSS/MIT · 80.7k GitHub stars

  VerdictMIT API client. Free core + self-host; pick it when the browser is the client, Bruno when Git is the source of truth.

  CatchVs Bruno (git-native *desktop* collections as files): Hoppscotch is web/self-host first, not “collections are just commits” by default. Cloud/workspace features and self-host ops are the real product surface — Enterprise exists for orgs. Not a mock/monitor platform.

• xhMIT HTTPie-compatible HTTP client as a Rust single binary

  Free / OSS · OSS/MIT · 8.1k GitHub stars

  VerdictMIT HTTPie-shaped HTTP CLI. Free forever; carry one binary when pip is the tax.

  CatchVs HTTPie (Python CLI UX) and curl: xh is the *Rust single-binary* cousin, not a plugin ecosystem and not every HTTPie feature. Incomplete parity is intentional (#4). curl still wins when the script must assume the OS already has it.

• ohaMIT HTTP load generator with realtime TUI (hey-inspired)

  Free / OSS · OSS/MIT · 10.6k GitHub stars

  VerdictMIT HTTP load TUI. Free forever; hammer your own staging and watch the chart.

  CatchVs hey (simple Go hammer), vegeta/k6 (scripted/scenarios), and curl loops: oha is the *interactive TUI load* CLI, not a full performance suite with thresholds-as-code. No browser/Web Vitals story. Point it at staging you own — load tests are still an attack if aimed at someone else.

• HurlApache-2.0 plain-text HTTP tests powered by curl

  Free / OSS · Apache-2.0 · 19.3k GitHub stars

  VerdictApache-2.0 HTTP test files. Free forever; commit the session, run it in CI.

  CatchVs xh/HTTPie (interactive HTTP CLIs) and Bruno/Hoppscotch (API *clients*): Hurl is the *plain-text test runner*, not a REPL client and not a collections GUI. You author `.hurl` files; it is not Postman-shaped collaboration. libcurl semantics apply.

• k6AGPL-3.0 scriptable load testing (JS) from Grafana

  Free / OSS · AGPL-3.0 · 32k GitHub stars

  VerdictAGPL-3.0 scriptable load. Free unmodified CLI/CI; Cloud k6 is the paid seat.

  CatchAGPL-3.0 network/copyleft — modifications you serve or distribute can trigger source obligations; do not treat k6 as MIT. Grafana Cloud k6 is a separate paid hosted product (execution, analysis, collaboration). Vs oha (MIT TUI hammer): k6 is the *scripted/scenario* suite, not a live ratatui chart. Point it at staging you own.

• mcp-remoteMIT npx stdio↔remote MCP proxy with OAuth support

  Free / OSS · OSS/MIT · 1.6k GitHub stars

  VerdictMIT remote-MCP stdio shim. Use until your client speaks OAuth remote natively.

  CatchVs SuperGateway (bidirectional stdio↔SSE/WS bridge): mcp-remote is the client-side remote+OAuth drop-in, not a capability server and not a full gateway product. Some clients already speak unauth remote MCP — you only need this for OAuth/legacy stdio hosts. Adds a local Node process in the path.

• SteelApache-2.0 browser API for AI agents — self-host or cloud

  Free / OSS · Apache-2.0 · 7.8k GitHub stars

  VerdictApache-2.0 agent browser API. Self-host Steel; pay Browserbase-shaped cloud only if you must.

  CatchVs Browserbase (managed fleet), Stagehand (AI Playwright layer), Browser Use (LLM browser framework): Steel is the browser sandbox/API — bring your own agent logic. Self-host means Chrome resource cost; cloud is freemium/paid convenience. Anti-bot arms race still applies.

• mcp2cliMIT runtime MCP/OpenAPI/GraphQL→CLI — zero codegen

  Free / OSS · OSS/MIT · 2.4k GitHub stars

  VerdictMIT MCP/OpenAPI/GraphQL CLI wrapper. Shell tools without shipping schemas every turn.

  CatchVs SuperGateway / mcp-remote (transport bridges) and MCP Inspector (debug UI): mcp2cli is a runtime CLI façade for APIs/MCP, not a gateway product and not an inspector. GraphQL mode needs introspection. You still trust whatever endpoint you point it at.

More with this tag (80)

• Agent Reach — MIT eyes for agents — public-web CLI, zero API fees
• Engram — MIT persistent agent memory — MCP, CLI, TUI, SQLite
• Firecrawl — AGPL-3.0 OSS + cloud scrape API — LLM-ready pages
• PostgREST — MIT instant REST API for any Postgres schema
• HyperFrames — HTML + CSS + seekable animation → deterministic MP4, built for agents
• Hishel — BSD-3 elegant HTTP caching for Python
• Supermemory — MIT memory/context engine with a local API
• SLayer — MIT embeddable semantic layer for agents — MCP, SQL expressions, dbt/Cube import
• Agent Native — Define an action once and expose it to agents and every UI surface
• Skillbox — Self-hosted versioned skills library with MCP and scoped clients
• Design Studio AI — Agent-first design workspace with MCP, CLI, and shared human edits
• Pi — MIT agent harness with coding CLI, unified LLM API, and TUI
• treg — Metered tool catalog and team vault for agent integrations
• CubeSandbox — Apache concurrent lightweight agent sandbox — RustVMM/KVM, E2B-compatible
• HarnessRouter CE — Apache self-hosted unified API over Codex, Claude Code, DSH, and peers
• ContextForge — Apache MCP+A2A+REST/gRPC→MCP gateway with governance + OTel
• CLI Proxy API — MIT local OpenAI/Claude/Gemini-compatible API in front of coding CLIs
• OpenAI Tunnel Client — Apache customer daemon for Secure MCP Tunnel to ChatGPT/Codex
• emcee — MIT turn any OpenAPI into an MCP server for Claude and friends
• FrontMCP — Apache-2.0 TypeScript-first MCP server framework (decorators, DI, OAuth)
• gutcheck — MIT semantic grep — filter lines with a local CPU model
• Floci — MIT free local AWS cloud API emulator (:4566 LocalStack-shaped)
• MetaMCP — MIT self-host MCP aggregator + middleware + inspector (one endpoint)
• Claude for Financial Services — Apache-2.0 finance reference agents/skills (Anthropic)
• Herdr — Apache-2.0 terminal runtime for multi-agent herds — state, panes, socket API
• Langflow — MIT visual agent/workflow builder — every flow as API + MCP tool
• awwwards-mcp — MIT design-inspiration MCP — Awwwards search, DNA, screenshots
• Rapid-MLX — Apache-2.0 local LLM server for Apple Silicon — OpenAI + Anthropic APIs, tool-call parsing tuned for coding agents
• eve — Apache-2.0 filesystem-first framework for durable AI agents — from Vercel
• MXC — MIT Microsoft SDK for isolating untrusted agent code — Rust, .NET, Node
• Dyad — Local, open-source AI app builder — a v0/Lovable/Bolt alternative on your own machine
• Crawlee — Apache-2.0 Node.js crawling and scraping library from Apify, HTTP or headless browser
• Higress — Apache-2.0 AI and API gateway on Envoy and Istio, with Wasm plugins, model proxying and MCP hosting
• Agent Client Protocol — Apache-2.0 LSP-for-agents: one protocol so any editor can talk to any coding agent
• llama.cpp — MIT local LLM inference in C/C++ on almost any hardware
• KEDA — Apache-2.0 CNCF event-driven autoscaling for Kubernetes
• chi — MIT minimal Go HTTP router built on net/http
• Kitten TTS — Apache-2.0 Python TTS library that runs on a CPU
• Gotenberg — MIT Docker API that turns HTML and Office files into PDFs
• go-zero — MIT Go web and RPC framework with goctl code generation
• pgvector — Open-source vector similarity search inside Postgres
• Gatus — Apache-2.0 health checks and status page with alerts
• CrowdSec — MIT open-source IDS/IPS and WAF with a community blocklist
• Komodo — GPL-3.0 build and deploy tool for Docker across many servers
• NetBox — Apache-2.0 source of truth for network and data-center infra
• Dgraph — Apache-2.0 distributed graph database with native GraphQL
• Dexie.js — Apache-2.0 friendly IndexedDB wrapper for the browser
• SeaORM — Apache-2.0 async ORM for Rust web services
• Nhost — MIT open-source Firebase alternative with Postgres and GraphQL
• lnd — MIT Lightning Network node daemon in Go
• Pay — MIT payments engine for Ruby on Rails
• dj-stripe — MIT Stripe data synced into Django models
• Meteroid — AGPL-3.0 usage-based pricing and billing platform
• notifiers — MIT one Python API for many notification providers
• react-hot-toast — MIT lightweight toast notifications for React
• mitmproxy — MIT interactive TLS-capable intercepting HTTP proxy
• Yaak — MIT desktop API client for REST, GraphQL and gRPC
• Artillery — MPL-2.0 load testing for HTTP, WebSockets and browsers
• Fumadocs — MIT docs framework for Next.js, Astro and Vite
• TinaCMS — Apache-2.0 Git-backed headless CMS for Markdown and MDX
• ShopifySharp — MIT .NET library for building Shopify apps
• Echo — MIT high-performance minimalist Go web framework
• Excelize — BSD-3 pure Go library to read and write Excel files
• Kratos — MIT Go framework for cloud-native microservices
• ComfyUI — GPL-3.0 node-graph engine and API for local image, video and audio models
• Hyperswitch Prism — Apache-2.0 stateless library: one payment API for Stripe, Adyen and more
• bgfx — BSD-2 cross-platform rendering library: bring your own engine
• Parse Server — Apache-2.0 self-hosted backend on Node.js with MongoDB or Postgres
• gptme — MIT terminal agent that edits files and runs shell and Python
• kubernetes-mcp-server — Apache-2.0 MCP server that talks to the Kubernetes API directly
• SMG (Shepherd Model Gateway) — Apache-2.0 Rust gateway that routes OpenAI and Anthropic API traffic across vLLM, SGLang, TRT-LLM and cloud models
• Fiber — MIT Express-style web framework for Go, built on fasthttp
• Gin — MIT HTTP web framework for Go with fast routing and middleware, built on net/http
• HTTPie — BSD-3-Clause human-friendly HTTP client for the terminal
• Resend — Email API designed for developers
• PlanetScale — Serverless MySQL with Vitess DNA
• LiteLLM — MIT OpenAI-compatible gateway to 100+ LLMs; Enterprise SSO paid
• Daytona — Freemium agent sandboxes — stateful envs, SDK/API/CLI
• MagicBell — Multichannel notification API + inbox; Builder free to 1k deliveries/mo
• Next.js Commerce — MIT App Router storefront template for headless Shopify