Feature

Server-Sent Events & Streaming Responses

Incrementally streamed HTTP responses.

137 providers 2803 APIs 129 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.

137 API providers on the APIs.io network offer server-sent events & streaming responses. The highest-rated are Amazon S3, SendGrid, Polygon, NVIDIA NIM, Vapi.

Providers

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

Exemplar 22 Complete, well-documented, and agent-ready
Amazon S3 Amazon Simple Storage Service (S3) is an object storage service offering industry-leading scalability, data... 17 APIs 78.1 SendGrid SendGrid is a cloud-based email delivery platform that provides reliable transactional and marketing email ... 63 APIs 77.0 Polygon Polygon (Polygon.io, rebranded as Massive in early 2026) provides real-time and historical market data APIs... 12 APIs 76.9 NVIDIA NIM NVIDIA NIM (NVIDIA Inference Microservices) is a catalog of GPU-accelerated, containerized AI inference mic... 11 APIs 75.7 Vapi Vapi is a San Francisco-based voice AI platform that lets developers build real-time, low-latency voice age... 15 APIs 75.7 Ashby Ashby is a modern all-in-one recruiting platform combining Applicant Tracking System (ATS), sourcing/CRM, i... 52 APIs 75.3 Plaid Plaid is a US financial-technology company and data-network aggregator that provides an API platform for bu... 31 APIs 75.2 Anthropic Anthropic is an AI safety company and creator of the Claude family of large language models (Opus, Sonnet, ... 24 APIs 75.0 Fastly Fastly is an edge cloud platform that helps customers create great digital experiences quickly, securely, a... 80 APIs 73.3 Factset FactSet creates flexible, open data and software solutions for tens of thousands of investment professional... 460 APIs 72.8 Mailchimp Mailchimp is an Intuit company providing a marketing automation platform and email marketing service for ma... 120 APIs 71.5 Meta Collection of Meta (Facebook) platform APIs for social networking, messaging, advertising, content publishi... 19 APIs 71.3 Youtube YouTube APIs provide programmatic access to YouTube data including videos, playlists, channels, user intera... 36 APIs 71.1 Claude Anthropic's Claude AI assistant API for natural language processing and conversation. 9 APIs 70.2 Adobe Adobe provides APIs and developer resources for its creative, document, and experience cloud platforms. Dev... 32 APIs 69.4 Amazon EFS Amazon Elastic File System (EFS) provides a simple, serverless, set-and-forget elastic file system for use ... 1 API 68.8 Raygun Raygun is an application monitoring platform that combines Crash Reporting, Real User Monitoring (RUM), and... 15 APIs 68.7 Amazon Data Exchange AWS Data Exchange makes it easy to find, subscribe to, and use third-party data in the cloud. Qualified dat... 6 APIs 68.2 Auth0 Auth0 (now part of Okta) is a leading identity-as-a-service platform providing authentication and authoriza... 76 APIs 68.0 Amazon Location Service Amazon Location Service provides location-based services including maps, places, routes, trackers, and geof... 1 API 67.3 fireblocks Fireblocks is an institutional digital-asset and stablecoin infrastructure company providing MPC-secured cu... 35 APIs 67.2 Cumulocity Cumulocity is an enterprise AIoT (Artificial Intelligence of Things) platform that connects, manages, and a... 39 APIs 66.7
Strong 41 Solid coverage with minor gaps
OpenRouter OpenRouter is an API platform that provides unified access to multiple AI language models through a single ... 7 APIs 65.4 Amazon IoT SiteWise AWS IoT SiteWise is a managed service that makes it easy to collect, store, organize, and monitor industria... 16 APIs 65.1 Blockfrost Blockfrost is a RESTful API service providing access to the Cardano blockchain and its ecosystem. It serves... 20 APIs 65.1 Recraft Recraft is a London-based AI design platform — founded in 2023 by Anna Veronika Dorogush (creator of the Ca... 5 APIs 64.8 Moniepoint Moniepoint is Africa's all-in-one financial platform for small and medium-sized businesses and individuals ... 19 APIs 64.7 Perplexity Perplexity AI is an answer engine that delivers accurate answers to complex questions using large language ... 12 APIs 64.3 Leonardo.AI Leonardo.AI is an Australian generative-AI company (acquired by Canva in July 2024) offering a Production A... 14 APIs 64.0 Salesforce Automation A collection of Salesforce APIs for automating business processes, sales operations, and customer relations... 42 APIs 63.9 Soracom Soracom is a global IoT cellular connectivity and platform provider headquartered in Tokyo, founded in 2014... 45 APIs 63.9 Argyle Argyle is a consumer-permissioned employment and income data platform. The REST API and Link SDK let lender... 26 APIs 63.6 Adobe Creative Cloud Adobe Creative Cloud is a suite of software and cloud services for graphic design, video editing, web devel... 24 APIs 63.2 Censys Censys is an internet intelligence and attack surface management platform that continuously scans the publi... 14 APIs 63.2 Canva APIs for the Canva design platform, enabling developers to integrate Canva's design tools and functionality... 12 APIs 63.0 Heroku Heroku is a cloud platform as a service (PaaS) that enables developers to build, run, and operate applicati... 14 APIs 63.0 OpsGenie OpsGenie is an incident management and alerting platform, now part of Atlassian, that helps operations team... 15 APIs 63.0 DroneDeploy DroneDeploy is the unified reality-capture platform for construction, agriculture, mining, energy, oil & ga... 3 APIs 62.8 Livepeer Livepeer is the open, permissionless protocol for video transcoding, streaming, and AI video inference, coo... 19 APIs 62.6 Amazon MediaTailor AWS Elemental MediaTailor is a channel assembly and personalized ad-insertion service that enables you to m... 10 APIs 62.5 Pluralsight APIs for the Pluralsight technology skills and engineering intelligence platform, providing access to cours... 14 APIs 62.5 Amazon MediaConnect AWS Elemental MediaConnect is a high-quality transport service for live video that provides the reliability... 8 APIs 62.4 Adobe Creative Suite Adobe Creative Suite is a collection of professional software applications for graphic design, video editin... 38 APIs 62.3 Barndoor Barndoor AI is the control plane for agentic AI, providing secure access and governance for AI agents and M... 13 APIs 62.1 Greenhouse Greenhouse Software is an enterprise applicant tracking system (ATS) and end-to-end hiring platform spannin... 27 APIs 62.1 Amazon Global Accelerator Amazon Global Accelerator is a networking service that improves the performance and availability of applica... 49 APIs 62.0 Amazon DMS AWS Database Migration Service (AWS DMS) helps you migrate databases to AWS quickly and securely. The sourc... 72 APIs 61.5 Bridge Bridge (Bridge Interactive / Bridge Data Output) is a Zillow Group company that runs the Bridge Platform — ... 13 APIs 61.4 Runway Runway is an applied AI research company that builds generative AI tools for creative professionals. Their ... 16 APIs 61.2 Google Quantum AI Google Quantum AI is Google's quantum-computing research and engineering arm, building superconducting quan... 15 APIs 61.1 Toolhouse Toolhouse is a Backend-as-a-Service platform for building, deploying, and managing "AI workers" (Toolhouse'... 8 APIs 60.9 Perforce Perforce Software provides enterprise-scale development tools, including version control, application lifec... 14 APIs 60.7 Pipedrive Pipedrive is a sales CRM and pipeline management tool focused on small and mid-market teams. The Pipedrive ... 48 APIs 60.6 Vonage Vonage (part of Ericsson) provides cloud communications APIs for voice, SMS, messaging, video, and verifica... 9 APIs 60.1 Giphy GIPHY is the world's largest library of GIFs, stickers, animated emoji, and Clips (GIFs with sound), with a... 11 APIs 59.5 Rollbar Rollbar is a real-time error tracking and monitoring platform for software teams. It automatically captures... 15 APIs 59.5 Triton One Triton One is a high-performance Solana RPC and blockchain infrastructure provider operating globally distr... 13 APIs 59.5 VesselFinder VesselFinder is a maritime intelligence company operating a global AIS vessel-tracking network (terrestrial... 10 APIs 59.5 Algorand Algorand is a pure proof-of-stake blockchain platform designed for speed, security, and decentralization. I... 19 APIs 59.0 Split Split, now part of Harness Feature Management and Experimentation, is a feature flag and experimentation pl... 21 APIs 59.0 Gainsight Gainsight is a customer success platform that helps companies retain and grow their customer base through d... 29 APIs 58.4 Livepeer Livepeer is a decentralized video infrastructure network. Independent orchestrators run GPU hardware to pro... 28 APIs 58.3 Smithery Smithery is an MCP server registry and hosting platform that lets developers discover, publish, and connect... 9 APIs 58.3
Developing 28 Usable, with meaningful gaps to close
Verisk Verisk (formerly ISO) is a leading data analytics and technology company serving the insurance, energy, and... 5 APIs 55.6 Google Apps Script The Apps Script API provides programmatic access to manage Google Apps Script projects, deployments, and ex... 4 APIs 54.1 Gemini Google's Gemini API provides access to state-of-the-art generative AI models for text generation, multimoda... 20 APIs 52.4 Forethought Forethought is a San Francisco-based generative AI customer-support platform. Its multi-agent product suite... 3 APIs 52.3 Tensor Tensor is the Solana-native NFT marketplace and trading protocol founded by Tensor HQ and now stewarded by ... 9 APIs 52.0 Mubert Mubert is a generative AI music platform that composes royalty-free, DMCA-free music in real time from mill... 6 APIs 51.7 Amazon Nova Amazon Nova is a new generation of state-of-the-art foundation models from Amazon that deliver a compelling... 3 APIs 51.3 Apache JMeter Apache JMeter is an open-source Java application designed for load testing functional behavior and measurin... 4 APIs 50.3 nOps nOps is an AI-powered cloud cost visibility and optimization platform that helps organizations reduce their... 2 APIs 50.0 Ariba Guided Buying SAP Ariba Guided Buying provides a consumer-like shopping experience for enterprise procurement, enabling e... 2 APIs 49.6 EVE Online EVE Online is a massively multiplayer online (MMO) space game published by CCP Games. The EVE Online third-... 50 APIs 49.5 Close Close is an inside-sales CRM with calling, email, SMS, and WhatsApp built in. The Close API exposes leads, ... 62 APIs 49.3 IMDb-API Community web service (operated under the IMDb-API / TV-API brand) providing movie, TV series and cast info... 6 APIs 49.0 Blockdaemon Blockdaemon is an institutional blockchain infrastructure company founded in 2017 by Konstantin Richter. It... 11 APIs 48.9 Google Google's public APIs and services. 125 APIs 48.8 MarineTraffic MarineTraffic is the leading maritime intelligence and AIS ship-tracking platform — now part of Kpler. The ... 14 APIs 46.3 Capella Space Capella Space operates a constellation of synthetic aperture radar (SAR) satellites and provides on-demand,... 9 APIs 45.7 Intercom Intercom is an AI-powered customer service platform that enables businesses to build seamless customized ex... 9 APIs 45.7 US Census Bureau The U.S. Census Bureau is the federal statistical agency responsible for producing data about the American ... 19 APIs 44.7 AspenTech AspenTech (Aspen Technology, Inc.) is a global leader in industrial software for asset optimization across ... 6 APIs 44.6 Argo CD Argo CD is a declarative, GitOps continuous delivery tool for Kubernetes that automates the deployment of a... 13 APIs 44.4 Ariba SAP Ariba provides cloud-based procurement and supply chain collaboration solutions. These APIs enable inte... 80 APIs 44.3 Apache POI Apache POI is a Java API for manipulating various file formats based upon the Office Open XML standards (OO... 4 APIs 44.1 Docling Docling is an open-source toolkit for parsing diverse document formats — PDF, DOCX, PPTX, XLSX, HTML, image... 18 APIs 44.0 Assertible Assertible provides a reliable first line of defense against web service failures by providing simple and p... 2 APIs 43.7 NOAA — National Oceanic and Atmospheric Administration The National Oceanic and Atmospheric Administration (NOAA) is the United States scientific and regulatory a... 24 APIs 43.1 NASA Open APIs NASA Open APIs is the National Aeronautics and Space Administration's unified, public developer portal expo... 34 APIs 42.5 Adobe Suite Collection of Adobe Creative Cloud and Experience Cloud APIs. 23 APIs 42.2
Thin 22 Limited public surface area
Test Plans Structured documentation outlining test objectives, scope, approach, resources, schedule, and deliverables ... 5 APIs 41.5 Blender Blender is the free and open source 3D creation suite supporting the entirety of the 3D pipeline including ... 2 APIs 41.4 CAT CAT is the brand name and ticker symbol for Caterpillar Inc. (NYSE: CAT), the world's leading manufacturer ... 2 APIs 41.2 Langflow Langflow is an open-source low-code visual builder for AI agents, RAG pipelines, and LangChain-based workfl... 15 APIs 41.1 Lex Machina Lex Machina is a legal analytics platform owned by LexisNexis that transforms raw court documents and docke... 21 APIs 40.8 Unity Unity is a real-time 3D content creation platform — the Unity engine powers cross-platform games, simulatio... 19 APIs 40.6 Tradeweb Tradeweb Markets is a leading global operator of electronic marketplaces for rates, credit, equities, and m... 5 APIs 40.2 Imgix imgix is a real-time image processing and CDN service that helps developers optimize images, improve page s... 2 APIs 38.7 Loadsmart Loadsmart is a digital freight technology company and 4PL that connects shippers, carriers, warehouses, and... 48 APIs 38.7 Alliance for OpenUSD The Alliance for OpenUSD (AOUSD) is a Linux Foundation project dedicated to promoting interoperability of 3... 2 APIs 38.3 Krea Krea is a real-time AI creative suite that lets designers, filmmakers, brand teams, and everyday creators g... 7 APIs 38.3 Amazon Audit Manager AWS Audit Manager helps you continuously audit your AWS usage to simplify how you assess risk and complianc... 6 APIs 37.7 Syndica Syndica is a Solana-only infrastructure company building developer infrastructure for Web3. Its production ... 4 APIs 34.5 Chainguard Chainguard builds, secures, and maintains a catalog of hardened, minimal container images and software supp... 6 APIs 34.1 Baker Hughes Baker Hughes is an energy technology company providing solutions to energy and industrial customers worldwi... 2 APIs 33.9 Greenly Greenly is a Paris-headquartered (with offices in London and New York) carbon accounting platform focused o... 7 APIs 33.2 Riskified Riskified (NYSE RSKD) is an Israeli ecommerce risk-management platform that uses machine learning and a glo... 7 APIs 31.7 Audatex Audatex (part of Solera Holdings) provides automotive claims and repair solutions with data and technology ... 3 APIs 31.6 Three.js Three.js is an open-source JavaScript 3D library originally created by Ricardo Cabello (mrdoob) in 2010 and... 6 APIs 30.4 Axonius Axonius is a cybersecurity asset management platform providing SaaS management, device discovery, and secur... 1 API 29.0 Apache Tapestry Apache Tapestry is a component-oriented framework for creating highly scalable web applications in Java. It... 1 API 28.6 Volvo Cars Volvo Cars is a Swedish premium automotive OEM (headquartered in Gothenburg, owned by Geely) that operates ... 4 APIs 28.6
Emerging 18 Early or largely undocumented
Certero Certero is an enterprise IT Asset Management (ITAM) software vendor whose flagship CerteroX platform unifie... 6 APIs 27.5 Bloomberg Indices Bloomberg Indices are a comprehensive family of fixed income, equity, commodity, and multi-asset benchmark ... 3 APIs 27.0 Bloomberg Query Language (BQL) Bloomberg Query Language (BQL) is a proprietary query language for accessing, filtering, aggregating, and c... 2 APIs 26.5 Wireshark Wireshark is the world's foremost and widely-used free and open-source network protocol analyzer. It lets y... 1 API 23.7 AstroPay AstroPay is a Uruguay-founded fintech and electronic money institution offering a multicurrency wallet, vir... 20 APIs 23.6 Benchmark Minerals Benchmark Mineral Intelligence is the world's leading market intelligence and price reporting agency for th... 1 API 21.8 Affiliated Managers Group Affiliated Managers Group (AMG) is a global asset management company that partners with outstanding indepen... 2 APIs 21.6 HPE Aruba Networking HPE Aruba Networking is the networking business unit of Hewlett Packard Enterprise (NYSE HPE), born of Arub... 10 APIs 21.3 Promptfoo Promptfoo is an open-source CLI and TypeScript/Node.js library for evaluating, red-teaming, and security-te... 20.9 Ecologi Ecologi is a Bristol, UK climate action platform and B Corp founded in 2019 that lets individuals and busin... 2 APIs 20.8 Scenario Scenario is a Paris- and San Francisco-headquartered AI platform for game asset generation founded in 2021 ... 5 APIs 20.5 TransDigm Group TransDigm Group is a leading global designer, producer, and supplier of highly engineered aerospace compone... 20.3 CCPA (California Consumer Privacy Act) The California Consumer Privacy Act (CCPA), amended by the California Privacy Rights Act (CPRA), is a state... 4 APIs 20.2 Sardine Sardine is a San Francisco-based fraud prevention, AML compliance, and risk management platform for fintech... 6 APIs 19.9 Allianz A German multinational financial services company and one of the world's largest insurance and asset manage... 19.7 Babylon.js Babylon.js is an Apache-2.0 licensed, TypeScript-first open-source 3D engine and rendering framework sponso... 18 APIs 19.7 Glass Health Glass Health is a San Francisco-based clinical AI company founded in 2021 by Dereck Paul (CEO) and Graham R... 18.8 CMA CGM CMA CGM is a Marseille-headquartered French container shipping, logistics, and port operator and the third-... 6 APIs 14.0
Minimal 6 Almost no public developer surface
Westlake Westlake Corporation is a global Fortune 500 manufacturer and supplier of materials and innovative products... 11.4 Catena-X Catena-X is the automotive industry's data space standard, published by Catena-X Automotive Network e.V. — ... 11.2 AutoGen Studio AutoGen Studio is a low-code / no-code developer GUI from Microsoft Research for rapidly prototyping, compo... 8.5 OctoAI OctoAI (formerly OctoML) was a Seattle-based AI inference platform founded in 2019 as a University of Washi... 5 APIs 8.5 TTM Technologies TTM Technologies, Inc. (NASDAQ: TTMI) is a leading global manufacturer of technology products, including mi... 6.1 Acre Homes Acre Homes is a North Carolina-based homeownership company whose mission is to "create the best way to expe... 5.0

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.

$0.05/min Vapi orchestration fee on Build plan; model and voice costs passed at cost$110B+ digital assets secured; $10B+ staked on Blockdaemon validators; 250K+ nodes launched; 80+ protocols200+ integration partners across HRIS, assessments (SHL, CodeSignal, HackerRank, CoderPad), background checks (HireRight, Checkr), video (Zoom), comms (Slack, Google Workspace, Microsoft 365), and contract / offer letter tools (Pave, Ironclad, Metaview)3D 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 AssertionsAddressables and Cloud Content Delivery for live asset updates without app re-submissionAfrica's largest merchant acquirer — ~10M business and individual accounts, $17B monthly TPV, 26M daily payments processedApproval ProcessesAssertionsAssessment 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 AssemblyClaims Assessment APIClaude 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 Assembly

Showing 40 of 129 declared variants