Feature

Server-Sent Events & Streaming Responses

Incrementally streamed HTTP responses.

116 providers 806 APIs 110 declared variants

Responses stream token-by-token or event-by-event over a long-lived HTTP connection. The default delivery mode for LLM completions and progressive result sets.

116 API providers on the APIs.io network offer server-sent events & streaming responses. The highest-rated are Anthropic, SendGrid, Plaid, Canva, Mailchimp.

Providers

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

Exemplar 14 Complete, well-documented, and agent-ready
AnthropicAnthropic is an AI safety company and the creator of the Claude family of large language models (Opus, Sonn...5 published contracts89.0SendGridSendGrid is a cloud-based email delivery platform, acquired by Twilio in 2019, that provides transactional ...44 published contracts87.5PlaidPlaid is a US financial-technology company and data-network aggregator that provides an API platform for bu...41 published contracts84.6CanvaCanva is the visual design platform used by hundreds of millions of people, and it exposes four distinct de...2 published contracts79.8MailchimpMailchimp is an Intuit company providing a marketing automation platform and email marketing service for ma...5 published contracts78.8Adobe SuiteAdobe operates one of the largest first-party API estates in software: 70 published OpenAPI and Swagger con...70 published contracts77.3AdobeAdobe provides APIs and developer resources for its creative, document, and experience cloud platforms. Dev...4 published contracts76.2CloseClose is an inside-sales CRM with calling, email, SMS, and WhatsApp built in. The Close API exposes leads, ...2 published contracts75.3Auth0Auth0 (now part of Okta) is a leading identity-as-a-service platform providing authentication and authoriza...4 published contracts72.1CumulocityCumulocity is an enterprise AIoT (Artificial Intelligence of Things) platform that connects, manages, and a...4 published contracts71.4Amazon S3Amazon Simple Storage Service (S3) is an object storage service offering industry-leading scalability, data...2 published contracts70.8GoogleGoogle is the parent of the Google API estate, publishing public APIs across Google Cloud (compute, data, A...9 published contracts70.1FireblocksFireblocks is an institutional digital-asset and stablecoin infrastructure company providing MPC-secured cu...1 published contract69.5Amazon EFSAmazon Elastic File System (EFS) provides a simple, serverless, set-and-forget elastic file system for use ...1 published contract66.5
Strong 26 Solid coverage with minor gaps
Amazon Location ServiceAmazon Location Service provides location-based services including maps, places, routes, trackers, and geof...1 published contract65.8PluralsightAPIs for the Pluralsight technology skills and engineering intelligence platform, providing access to cours...30 published contracts65.8Amazon IoT SiteWiseAWS IoT SiteWise is a managed service that makes it easy to collect, store, organize, and monitor industria...1 published contract65.3FastlyFastly is an edge cloud platform that helps customers create great digital experiences quickly, securely, a...22 published contracts65.3Massive (formerly Polygon.io)Polygon (Polygon.io, rebranded as Massive in early 2026) provides real-time and historical market data APIs...70 published contracts64.9CensysCensys is an internet intelligence and attack surface management platform that continuously scans the publi...2 published contracts63.8FactsetFactSet creates flexible, open data and software solutions for tens of thousands of investment professional...142 published contracts63.6PerplexityPerplexity AI is an answer engine that delivers accurate answers to complex questions using large language ...2 published contracts63.2Amazon MediaConnectAWS Elemental MediaConnect is a high-quality transport service for live video that provides the reliability...1 published contract62.7Leonardo.AILeonardo.AI is an Australian generative-AI company (acquired by Canva in July 2024) offering a Production A...17 published contracts62.4RaygunRaygun is an application monitoring platform that combines Crash Reporting, Real User Monitoring (RUM), and...1 published contract62.3RiskifiedRiskified (NYSE RSKD) is an Israeli ecommerce risk-management platform that uses machine learning and a glo...10 published contracts61.6Amazon MediaTailorAWS Elemental MediaTailor is a channel assembly and personalized ad-insertion service that enables you to m...1 published contract60.9Amazon NovaAmazon Nova is a new generation of state-of-the-art foundation models from Amazon that deliver a compelling...1 published contract60.2YoutubeYouTube APIs provide programmatic access to YouTube data including videos, playlists, channels, user intera...5 published contracts59.6Amazon Data ExchangeAWS Data Exchange makes it easy to find, subscribe to, and use third-party data in the cloud. Qualified dat...1 published contract59.4NVIDIA NIMNVIDIA NIM (NVIDIA Inference Microservices) is a catalog of GPU-accelerated, containerized AI inference mic...3 published contracts59.1BarndoorBarndoor AI is the control plane for agentic AI, providing secure access and governance for AI agents and M...1 published contract59.0Amazon Global AcceleratorAmazon Global Accelerator is a networking service that improves the performance and availability of applica...1 published contract58.5LoadsmartLoadsmart is a digital freight technology company and 4PL that connects shippers, carriers, warehouses, and...3 published contracts58.2MetaCollection of Meta (Facebook) platform APIs for social networking, messaging, advertising, content publishi...19 APIs56.5ClaudeAnthropic's Claude AI assistant API for natural language processing and conversation.1 published contract56.2Adobe Creative CloudAdobe Creative Cloud is a suite of software and cloud services for graphic design, video editing, web devel...4 published contracts55.9GiphyGIPHY is the world's largest library of GIFs, stickers, animated emoji, and Clips (GIFs with sound), with a...1 published contract55.6BlockdaemonBlockdaemon is an institutional blockchain infrastructure company founded in 2017 by Konstantin Richter. It...15 published contracts55.0PipedrivePipedrive is a sales CRM and pipeline management tool focused on small and mid-market teams. The Pipedrive ...2 published contracts54.6
Developing 30 Usable, with meaningful gaps to close
Google Quantum AIGoogle Quantum AI is Google's quantum-computing research and engineering arm, building superconducting quan...1 published contract53.7OpenRouterOpenRouter is an API platform that provides unified access to multiple AI language models through a single ...1 published contract53.5Amazon DMSAWS Database Migration Service (AWS DMS) helps you migrate databases to AWS quickly and securely. The sourc...2 published contracts53.0IntercomIntercom is an AI-powered customer service platform that enables businesses to build seamless customized ex...1 published contract52.9Adobe Creative SuiteAdobe Creative Suite is a collection of professional software applications for graphic design, video editin...4 published contracts51.6BlockfrostBlockfrost is a RESTful API service providing access to the Cardano blockchain and its ecosystem. It serves...2 published contracts51.4ToolhouseToolhouse is a Backend-as-a-Service platform for building, deploying, and managing "AI workers" (Toolhouse'...1 published contract50.3AxoniusAxonius is a cybersecurity asset management platform (Axonius Asset Cloud) that aggregates device, user, cl...1 API49.9RunwayRunway is an applied AI research company that builds generative AI tools for creative professionals. Their ...9 published contracts49.9BridgeBridge (Bridge Interactive / Bridge Data Output) is a Zillow Group company that runs the Bridge Platform — ...3 published contracts49.7Triton OneTriton One is a high-performance Solana RPC and blockchain infrastructure provider operating globally distr...3 published contracts49.0OpsGenieOpsGenie is an incident management and alerting platform, now part of Atlassian, that helps operations team...12 published contracts48.9AudatexAudatex (a Solera company) provides automotive claims and repair solutions with data and technology service...5 published contracts48.7Benchmark MineralsBenchmark Mineral Intelligence is the world's leading market intelligence and price reporting agency for th...1 published contract48.7RollbarRollbar is a real-time error tracking and monitoring platform for software teams. It automatically captures...4 published contracts48.4SoracomSoracom is a global IoT cellular connectivity and platform provider headquartered in Tokyo, founded in 2014...10 published contracts48.4AssertibleAssertible provides a reliable first line of defense against web service failures by providing simple and p...1 published contract48.3HerokuHeroku is a cloud platform as a service (PaaS) that enables developers to build, run, and operate applicati...1 published contract48.2IMDb-APICommunity web service (operated under the IMDb-API / TV-API brand) providing movie, TV series and cast info...1 published contract47.2MoniepointMoniepoint is Africa's all-in-one financial platform for small and medium-sized businesses and individuals ...13 published contracts47.1PerforcePerforce Software provides enterprise-scale development tools, including version control, application lifec...1 published contract46.8EVE OnlineEVE Online is a massively multiplayer online (MMO) space game published by CCP Games. The EVE Online third-...7 published contracts45.4US Census BureauThe U.S. Census Bureau is the federal statistical agency responsible for producing data about the American ...7 published contracts45.3VesselFinderVesselFinder is a maritime intelligence company operating a global AIS vessel-tracking network (terrestrial...2 published contracts44.8TensorTensor is the Solana-native NFT marketplace and trading protocol founded by Tensor HQ and now stewarded by ...2 published contracts42.0LangflowLangflow is an open-source low-code visual builder for AI agents, RAG pipelines, and LangChain-based workfl...1 published contract41.5NOAA — National Oceanic and Atmospheric AdministrationThe National Oceanic and Atmospheric Administration (NOAA) is the United States scientific and regulatory a...1 published contract40.9AlgorandAlgorand is a pure proof-of-stake blockchain platform designed for speed, security, and decentralization. I...3 published contracts40.8MarineTrafficMarineTraffic is the leading maritime intelligence and AIS ship-tracking platform — now part of Kpler. The ...9 published contracts40.5Apache JMeterApache JMeter is an open-source Java application designed for load testing functional behavior and measurin...1 published contract40.0
Thin 25 Limited public surface area
LivepeerLivepeer is a decentralized video infrastructure network. Independent orchestrators run GPU hardware to pro...4 published contracts39.2ForethoughtForethought is a San Francisco-based generative AI customer-support platform. Its multi-agent product suite...2 published contracts38.3DoclingDocling is an open-source toolkit for parsing diverse document formats — PDF, DOCX, PPTX, XLSX, HTML, image...2 published contracts38.0KreaKrea is a real-time AI creative suite that lets designers, filmmakers, brand teams, and everyday creators g...1 published contract37.7VeriskVerisk (formerly ISO) is a leading data analytics and technology company serving the insurance, energy, and...1 published contract37.5SplitSplit, now part of Harness Feature Management and Experimentation, is a feature flag and experimentation pl...2 published contracts36.5SyndicaSyndica is a Solana-only infrastructure company building developer infrastructure for Web3. Its production ...4 APIs36.4Google Apps ScriptThe Apps Script API provides programmatic access to manage Google Apps Script projects, deployments, and ex...1 published contract36.2ScenarioScenario is a Paris- and San Francisco-headquartered AI platform for game asset generation founded in 2021 ...5 APIs34.3MubertMubert is a generative AI music platform that composes royalty-free, DMCA-free music in real time from mill...1 published contract34.2Ariba Guided BuyingSAP Ariba Guided Buying provides a consumer-like shopping experience for enterprise procurement, enabling e...2 APIs34.0Amazon Audit ManagerAWS Audit Manager helps you continuously audit your AWS usage to simplify how you assess risk and complianc...1 published contract32.6GreenlyGreenly is a Paris-headquartered (with offices in London and New York) carbon accounting platform focused o...1 published contract32.3Capella SpaceCapella Space operates a constellation of synthetic aperture radar (SAR) satellites and provides on-demand,...1 published contract31.9AspenTechAspenTech (Aspen Technology, Inc.) is a global leader in industrial software for asset optimization across ...1 published contract31.4CATCAT is the brand name and ticker symbol for Caterpillar Inc. (NYSE: CAT), the world's leading manufacturer ...1 published contract31.4Lex MachinaLex Machina is a legal analytics platform owned by LexisNexis that transforms raw court documents and docke...1 published contract31.2Baker HughesBaker Hughes is an energy technology company providing solutions to energy and industrial customers worldwi...2 APIs30.9nOpsnOps is an AI-powered cloud cost visibility and optimization platform that helps organizations reduce their...1 published contract30.8Volvo CarsVolvo Cars is a Swedish premium automotive OEM (headquartered in Gothenburg, owned by Geely) that operates ...4 APIs29.5Alliance for OpenUSDThe Alliance for OpenUSD (AOUSD) is a Linux Foundation project dedicated to promoting interoperability of 3...2 APIs28.3BlenderBlender is the free and open source 3D creation suite supporting the entirety of the 3D pipeline including ...2 APIs27.8Affiliated Managers GroupAffiliated Managers Group (AMG) is a global asset management company that partners with outstanding indepen...4 published contracts27.4Apache POIApache POI is a Java API for manipulating various file formats based upon the Office Open XML standards (OO...1 published contract26.8Imgiximgix is a real-time image processing and CDN service that helps developers optimize images, improve page s...1 published contract26.8
Emerging 17 Early or largely undocumented
Apache TapestryApache Tapestry is a component-oriented framework for creating highly scalable web applications in Java. It...1 API25.9Three.jsThree.js is an open-source JavaScript 3D library originally created by Ricardo Cabello (mrdoob) in 2010 and...6 APIs24.4ChainguardChainguard builds, secures, and maintains a catalog of hardened, minimal container images and software supp...6 APIs22.8HPE Aruba NetworkingHPE Aruba Networking is the networking business unit of Hewlett Packard Enterprise (NYSE HPE), born of Arub...10 APIs22.4SardineSardine is a San Francisco-based fraud prevention, AML compliance, and risk management platform for fintech...6 APIs21.4EcologiEcologi is a Bristol, UK climate action platform and B Corp founded in 2019 that lets individuals and busin...2 APIs20.9WiresharkWireshark is the world's foremost and widely-used free and open-source network protocol analyzer. It lets y...1 API20.5Bloomberg IndicesBloomberg Indices are a comprehensive family of fixed income, equity, commodity, and multi-asset benchmark ...3 APIs17.6TradewebTradeweb Markets is a leading global operator of electronic marketplaces for rates, credit, equities, and m...5 APIs17.4Bloomberg Query Language (BQL)Bloomberg Query Language (BQL) is a proprietary query language for accessing, filtering, aggregating, and c...2 APIs17.1AstroPayAstroPay is a Uruguay-founded fintech and electronic money institution offering a multicurrency wallet, vir...20 APIs16.6Babylon.jsBabylon.js is an Apache-2.0 licensed, TypeScript-first open-source 3D engine and rendering framework sponso...18 APIs15.2CerteroCertero is an enterprise IT Asset Management (ITAM) software vendor whose flagship CerteroX platform unifie...6 APIs14.7CMA CGMCMA CGM is a Marseille-headquartered French container shipping, logistics, and port operator and the third-...6 APIs14.3Glass HealthGlass Health is a San Francisco-based clinical AI company founded in 2021 by Dereck Paul (CEO) and Graham R...11.8TransDigm GroupTransDigm Group is a leading global designer, producer, and supplier of highly engineered aerospace compone...11.6AutoGen StudioAutoGen Studio is a low-code / no-code developer GUI from Microsoft Research for rapidly prototyping, compo...11.2
Minimal 4 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.

$110B+ digital assets secured; $10B+ staked on Blockdaemon validators; 250K+ nodes launched; 80+ protocols3D assets and a Volvo simulator surface for digital and immersive product experiences.3D model generation via Rodin V2 and 3D model asset management3rd-largest container carrier worldwide; fleet of 593 vessels and 4.5M TEU capacity6,000+ expert witnesses trackedAIS vessel positions (live + delayed)API Test AssertionsAfrica's largest merchant acquirer — ~10M business and individual accounts, $17B monthly TPV, 26M daily payments processedAssertionsAssessment AccessAssessment and PlanAssessment delegation to process owners and resource ownersAsset DiscoveryAsset LibraryAsset Library SystemAsset ManagementAsset Management IntegrationAsset Manager DAM and Asset CleanupAsset ModelingAsset Performance ManagementAsset PipelineAsset ResolutionAsset TelematicsAsset TrackingAsset editingAsset storage (5 GB Free, 100/500 GB paid)Carbon Project Assessment Framework (CPAF) and Nature Project Assessment Framework (NPAF)Cards-as-a-Service issuing for businesses (virtual and physical, branded)Certification: third-party conformity assessment via TÜV Rheinland and TÜV SÜDChainStream real-time streaming API — transactionsSubscribe, slotsSubscribe, blocksSubscribe over WebSocket JSON-RPC 2.0 at wss://chainstream.api.syndica.ioChannel AssemblyClaude Managed Agents (beta) — Agents, Sessions, Environments with SSE streaming and managed sandboxesContent management and digital asset managementContext Variables — typed values (string, number, boolean, list, object) passed into Solve conversationsCross-Asset Data AccessCustom AssemblyDeployment Tracking — release markers correlated with new/regressed error groupsDigital Asset ManagementDigital Twin Manager (DTM) — asset modeling, hierarchies, computed smart functions, custom propertiesDispute Resolve — automated chargeback representment and evidence assembly across major payment gateways

Showing 40 of 110 declared variants

Work with this as data

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

One button, every client — Claude, Cursor, VS Code and the rest.

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.
All 92 tools →

Call it yourself

curl for this page
Search the catalog
curl "https://apis.io/api/v1/search?q=server-sent-events&limit=10"
Everything under a tag
curl "https://apis.io/api/v1/tags/server-sent-events"

Discovery needs no key. Ratings and market analysis are Pro.

Get an API key

Free tier, no form to fill in. Signing in shares your email address with us — we store it to create your key and to recognise you if you sign in with another provider. See our Privacy Policy and Terms.

A second provider on the same verified email joins the account you already have.