Feature

Open Source

Source code published under an open license.

113 providers 462 APIs 109 declared variants

The implementation is openly licensed and publicly readable, so integrators can audit behavior, fork, and contribute. Also changes the risk calculus on vendor continuity.

113 API providers on the APIs.io network offer open source. The highest-rated are GitLab, Outbrain, Buildkite, Airbyte, Daytona.

Providers

Ranked by API Evangelist rating — Exemplar and Strong are expanded by default.

Exemplar 8 Complete, well-documented, and agent-ready
Strong 24 Solid coverage with minor gaps
PaperspacePaperspace is a GPU cloud platform for AI, ML, and 3D rendering workloads, acquired by DigitalOcean in 2023...4 published contracts65.7Commerce LayerCommerce Layer is the headless, multi-market commerce API used by global brands to sell everywhere — web, m...4 published contracts65.6FireblocksFireblocks is an institutional digital-asset and stablecoin infrastructure company providing MPC-secured cu...7 published contracts65.5RedisRedis is an open source, in-memory data structure store used as a database, cache, message broker, and stre...1 published contract65.2n8nn8n is a fair-code workflow automation and iPaaS platform with AI-agent tooling. It exposes an instance-sco...1 published contract64.9IBM QuantumIBM Quantum is IBM's quantum computing program — the operator of the IBM Quantum Platform (quantum.cloud.ib...6 published contracts64.3Highlight (highlight.io)Highlight (highlight.io) is the open-source, full-stack monitoring platform — session replay, error monitor...5 published contracts63.6UmamiUmami is an open source, privacy-first web analytics platform that provides website traffic insights withou...7 APIs63.5AnkrAnkr is a Web3 infrastructure provider whose multichain RPC, Advanced API, liquid staking, contract automat...4 published contracts62.3StytchStytch is an authentication and identity infrastructure provider. Its Consumer and B2B APIs cover passwordl...4 published contracts61.9D-WaveD-Wave Quantum Inc. (NYSE: QBTS) is the leader in commercial quantum annealing computing and developer of t...4 published contracts61.2ThingsBoardThingsBoard is an open-source IoT platform for device connectivity, data collection, processing, and visual...15 published contracts61.2MewsMews is a cloud-native hospitality operating system serving 15,000+ hotels, hostels, and vacation-rental pr...3 published contracts60.7ServiceTitanServiceTitan is the operating system for the trades — all-in-one field service management software for resi...8 published contracts59.8Google Quantum AIGoogle Quantum AI is Google's quantum-computing research and engineering arm, building superconducting quan...1 published contract57.7HyperbolicHyperbolic is an open-access AI cloud and decentralized GPU marketplace serving 200,000+ builders with affo...5 published contracts57.7NanonetsNanonets is a no-code document AI and OCR platform that combines a custom-model OCR API, pre-built document...3 published contracts57.6LichessLichess is a free, ad-free, open-source online chess server operated by a French nonprofit and powered enti...2 published contracts57.0Leonardo.AILeonardo.AI is an Australian generative-AI company (acquired by Canva in July 2024) offering a Production A...14 published contracts56.9Academy Software FoundationThe Academy Software Foundation (ASWF) is a Linux Foundation project that supports open source software dev...14 APIs56.8DescopeDescope is a customer and agentic identity access management (CIAM) platform founded in 2022 by veterans of...1 published contract56.4Pocket NetworkPocket Network is the decentralized RPC layer of Web3 — a permissionless, fully open data delivery protocol...3 published contracts55.5CivitaiCivitai is the largest open community for Stable Diffusion, SDXL, Flux, and video AI models — hosting over ...2 published contracts55.4PipedreamPipedream is a developer-centric integration platform providing three product lines: Workflows (code-level ...2 published contracts54.7
Developing 29 Usable, with meaningful gaps to close
VespaVespa is an open-source AI search engine, big-data serving engine, and vector database originally developed...3 published contracts54.2TIDALTIDAL is a high-fidelity music streaming service owned by Block (Square's parent, acquired 2021) offering H...8 published contracts54.1Beatoven.aiBeatoven.ai is an Indian generative-music startup (Bengaluru, founded 2021) building text-to-music and text...1 published contract53.1EncoreEncore is a backend application framework and developer cloud that lets engineering teams build type-safe d...2 published contracts52.5BackpackBackpack is a Solana-first crypto company founded by Armani Ferrante and Tristan Yver — the same team behin...1 published contract52.2ConektaConekta is a Mexico-based payment processor that lets businesses accept credit and debit cards, OXXO cash v...2 published contracts52.0Octopus EnergyOctopus Energy is a UK-founded retail energy supplier and the parent of Kraken Technologies, the AI-powered...1 published contract51.6WooCommerceWooCommerce is the world's most popular open-source eCommerce platform, built on WordPress. It provides a c...2 published contracts49.2TensorTensor is the Solana-native NFT marketplace and trading protocol founded by Tensor HQ and now stewarded by ...2 published contracts49.01NCE1NCE is a Cologne-headquartered global IoT connectivity provider best known for the IoT Lifetime Flat — a s...15 published contracts48.9ChromaChroma (Chroma DB) is an open-source AI-native embedding database designed to make it easy to build LLM app...2 published contracts48.7arXivarXiv is the open-access e-print repository operated by Cornell Tech, hosting more than two million preprin...2 published contracts48.1ContinueContinue is the open-source AI code assistant for VS Code and JetBrains, distributed under Apache 2.0. The ...1 published contract47.2LangWatchLangWatch is an open-source LLM observability, evaluation, and AI agent testing platform. Built around Open...1 published contract46.6Triton OneTriton One is a high-performance Solana RPC and blockchain infrastructure provider operating globally distr...3 published contracts46.4NangoNango.dev is a developer infrastructure platform that simplifies building product integrations with externa...1 published contract44.8CerbosCerbos is an open-core, language-agnostic, scalable authorization platform that decouples access control fr...1 published contract44.1ApiaryApiary is an API design and documentation platform, now part of Oracle Cloud Infrastructure. With 486,000+ ...1 published contract43.9PackagistPackagist is the default package repository for Composer, the PHP dependency manager. It indexes over 454,0...1 published contract43.5Radio BrowserRadio Browser is a free, community-driven directory of internet radio stations. The project publishes a pub...1 published contract43.0ForethoughtForethought is a San Francisco-based generative AI customer-support platform. Its multi-agent product suite...2 published contracts42.7OpenHandsOpenHands (by All Hands AI, formerly OpenDevin) is an open-source autonomous coding agent platform. Ships a...1 published contract42.7PokéAPIPokéAPI (pokeapi.co) is a free, open-source RESTful and GraphQL API serving comprehensive Pokémon data — in...1 published contract42.4Analog DevicesAnalog Devices (ADI) is a global semiconductor company designing high-performance analog, mixed-signal, and...4 APIs41.8Department of Veterans Affairs (VA Lighthouse)VA Lighthouse is the US Department of Veterans Affairs' developer API platform. Published at developer.va.g...24 published contracts40.4TypesenseTypesense is a fast, typo-tolerant, open-source search engine designed for developer productivity. It provi...2 published contracts40.3ipifyipify operates two complementary IP APIs. The free Public IP Address API (api.ipify.org, api6.ipify.org, ap...3 APIs39.7crates.iocrates.io is the official package registry for the Rust programming language, operated by the crates.io tea...2 published contracts39.4CHAOSSCHAOSS (Community Health Analytics in Open Source Software) is a Linux Foundation project that develops met...2 published contracts39.3
Thin 28 Limited public surface area
AgStack FoundationAgStack Foundation is a Linux Foundation project providing open-source digital infrastructure for the agric...3 published contracts39.2Children's Hospital of PhiladelphiaFounded in 1855 as the first hospital in the United States dedicated to the healthcare of children, Childre...1 published contract39.0DoclingDocling is an open-source toolkit for parsing diverse document formats — PDF, DOCX, PPTX, XLSX, HTML, image...2 published contracts38.3KreaKrea is a real-time AI creative suite that lets designers, filmmakers, brand teams, and everyday creators g...1 published contract37.8FrankfurterFrankfurter is an open-source (MIT) currency exchange rates API that blends foreign-exchange reference rate...2 published contracts37.2SyndicaSyndica is a Solana-only infrastructure company building developer infrastructure for Web3. Its production ...4 APIs36.4ACI.devACI.dev (Aipolabs Agent-Computer Interface) is an open-source tool-calling platform that hooks AI agents in...1 published contract34.9TurborepoTurborepo is a high-performance build system for JavaScript and TypeScript codebases, built by Vercel and w...1 published contract34.3ScenarioScenario is a Paris- and San Francisco-headquartered AI platform for game asset generation founded in 2021 ...5 APIs34.0JitsiJitsi is a collection of free and open-source projects for secure, simple, and scalable real-time video con...10 APIs33.2McKinsey & CompanyMcKinsey & Company is the senior partner of the MBB triumvirate of global strategy and management consultin...33.0CieloCielo is one of the largest Brazilian card acquirers and a publicly traded company (B3:CIEL3), originally f...13 APIs32.7AudiomackAudiomack is an on-demand music streaming and audio discovery platform that lets artists and creators uploa...1 published contract31.8FormantFormant is a San Francisco–based robotics and physical-operations cloud platform that lets companies operat...1 published contract31.8Quote GardenQuote Garden is a free, open-source REST API that serves more than 75,000 famous quotes. Built by Prathames...1 published contract31.4ApivaultApivault is an open-source directory and gateway for discovering public APIs. The platform catalogs thousan...2 published contracts30.8Cypress SemiconductorCypress Semiconductor was a US-based semiconductor company known for its PSoC programmable system-on-chip m...6 APIs30.7XanaduXanadu is a Canadian photonic quantum computing company building room-temperature, fault-tolerant, scalable...14 APIs30.7Random User GeneratorFree random user data API for generating realistic fake user profiles with names, addresses, photos, and co...1 API30.6Eyevinn TechnologyEyevinn Technology is a Stockholm, Sweden based video streaming consultancy and open source company special...8 APIs30.4GlamaGlama is an all-in-one AI workspace combining an MCP server marketplace and registry, a managed MCP gateway...7 APIs29.6Volvo CarsVolvo Cars is a Swedish premium automotive OEM (headquartered in Gothenburg, owned by Geely) that operates ...4 APIs29.4BMW ConnectedDriveBMW ConnectedDrive is BMW Group's umbrella for connected vehicle services spanning navigation, remote servi...1 published contract28.6RenovateRenovate is an open source automated dependency update bot maintained by Mend. It scans repositories for re...6 APIs28.1American AirlinesAmerican Airlines is one of the world's largest airlines, operating an extensive domestic and international...1 published contract27.6FirelyFirely is an Amsterdam-based health IT company and one of the original co-developers of the HL7 FHIR (Fast ...1 published contract26.8Deutsche TelekomDeutsche Telekom AG is Europe's largest telecommunications operator, headquartered in Bonn, Germany, servin...8 published contracts26.5RakenRaken is a San Diego-based construction technology company providing a field-first daily reporting and fiel...1 API26.5
Emerging 18 Early or largely undocumented
YarnYarn is an open-source JavaScript package manager and project manager originally created at Facebook in 201...10 APIs25.1SignifydSignifyd is an ecommerce fraud prevention, chargeback protection, and revenue optimization platform. Its Co...8 APIs25.0Three.jsThree.js is an open-source JavaScript 3D library originally created by Ricardo Cabello (mrdoob) in 2010 and...6 APIs24.4CasdoorCasdoor is an open-source, AI-first identity and access management (IAM) and MCP gateway authentication ser...1 published contract23.8QuEra ComputingQuEra Computing is a Boston-based neutral-atom quantum computing company (founded 2018) that operates Aquil...8 APIs22.3SSTSST is an open source TypeScript framework for building full-stack applications on your own infrastructure....2 APIs21.0QuantinuumQuantinuum is an integrated quantum computing company formed by the 2021 merger of Honeywell Quantum Soluti...9 APIs20.4PasqalPasqal is a French neutral-atom quantum computing company headquartered in Palaiseau, France and co-founded...8 APIs18.7pnpmpnpm is a fast, disk space efficient package manager for JavaScript and Node.js projects. It uses a content...5 APIs18.7Apache Software FoundationThe Apache Software Foundation (ASF) is a 501(c)(3) nonprofit organization that provides open source softwa...1 API18.1SonySony Group Corporation is a Japanese multinational spanning electronics, gaming, entertainment, image senso...4 APIs17.4GSKGSK plc (formerly GlaxoSmithKline, rebranded in May 2022) is a global biopharma headquartered in the United...17.1SatellogicSatellogic is an Argentine-founded, U.S.-listed (NASDAQ: SATL) vertically integrated Earth observation comp...6 APIs15.3CometComet is Perplexity's AI-native browser built on Chromium (Blink), integrating Perplexity Search and an age...14.0BoschBosch is a German multinational engineering and technology company producing automotive components, industr...5 APIs13.7ChangelogChangelog is a media company and podcast network for developers covering open source and software developme...4 APIs13.4AutomatischAutomatisch is an open source business automation tool and self-hosted alternative to Zapier that connects ...1 API12.7Refact.aiRefact.ai is an open-source, local-first AI coding assistant and autonomous software-engineering agent buil...2 APIs12.6
Minimal 6 Almost no public developer surface

What Providers Actually Declared

This feature is a canonical term. These are the free-text strings providers wrote in their own apis.yml that map onto it.

100% open source under Apache 2.0 (with separate commercial license for `highlight.io/` and `enterprise/` directories)25+ open-source inference models — Llama 3.1 8B/70B/405B, Qwen 2.5, DeepSeek V3, DeepSeek R1, Hermes 3, Mistral, Llama 3.2 Vision, Qwen2-VL300+ Open Source Projects3D Scene module with custom-layer extensibility (open-source 3d-viewer-module)AGPL-3.0 Open SourceAll Google Quantum AI open-source software is Apache 2.0 licensedApache 2.0 LicenseApache 2.0 Open Source LicenseApache 2.0 open-source licensing for pytket, qnexus, lambeq, Guppy, Selene, QermitAutoChain — open-source lightweight framework for building and testing LLM agents (1.8k+ GitHub stars)Browser-side background-removal JS library and Blender texturing plugin available as open sourceCompanion BMW Car IT open-source stack (joynr, ramses, MoCOCrW, python-dlt) underpinning connected-vehicle middlewareCore: free open-source self-managedFirely .NET SDK — official open-source C# FHIR library (de-facto reference SDK)Free open-source MCP server hostingFree open-source WordPress pluginFree, ad-free, open-source online chess server operated by a French nonprofit, funded by donationsGSK Biostatistics Open SourceHosted Flow app (React) with full source available for self-hostingHosted micro frontends: checkout, cart, my-account, microstore, identity — each open-source on GitHubKrea Realtime experience with sub-50ms image generation and an open-source Realtime 14B autoregressive video model distilled from Wan 2.1 (CC BY-NC-SA 4.0)MIT licensed, no required runtime dependencies, runs in browser, Node.js, Electron, Tauri, Deno, and React NativeMIT licensed, open source on GitHub (vercel/turborepo)MIT-licensed open sourceMIT-licensed open source codebase (composer/packagist) — operated, not designed for reuseMulti-turn agent simulations with User Simulator and Judge Agents (open-source `scenario` framework)Ocean SDK — Python open-source SDK covering dimod, dwave-system, dwave-cloud-client, hybrid, samplersOfficial OpenAPI 3.1 specification published under MIT license at github.com/conekta/openapiOn-chain programs are open-source (Apache-2.0) Anchor programs published as IDLs, npm packages, and Rust cratesOpen SourceOpen Source (BSD-3-Clause)Open Source (MIT)Open Source Cloud (OSC)Open Source EcosystemOpen Source FocusOpen Source GovernanceOpen Source InfrastructureOpen Source IoTOpen Source LicensingOpen Source MIT License

Showing 40 of 109 declared variants

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Every feature here is available over the APIs.io API and to AI agents over MCP. Features is not yet its own endpoint on the v1 API. Reach it through catalog search and the tag graph, or the MCP server.

MCP server

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https://apis.io/mcp

Tools for features

3 MCP tools reach this
  • apis_io_searchSTART HERE — APIs, providers and tags for one query, each with its total.
  • resolveTurn a domain, URL or GitHub org into the provider it belongs to.
  • find_cohortsEvery scored population of providers in the catalog.
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Call it yourself

curl for this page
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curl "https://apis.io/api/v1/search?q=open-source&limit=10"
Everything under a tag
curl "https://apis.io/api/v1/tags/open-source"

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