YC API
143 Y Combinator companies tagged API, most in W22 (17).
Companies per batch
Companies
143 of 143 companies
ArchalS26 · AIAPI sandboxes, built for AI agents
ClickS26 · AIResearch services for ChatGPT and Claude
Luca IQS26 · AIAPI-first tax engine for CPA firms and developers
Keyframe LabsX26 · AIBring AI to life with the world's best interactive avatars
CaptainW26 · AISelf-tuning file search for AI agents
SalusW26 · AIGuardrails to validate your agent's actions before they execute
ParseF25 · DataBuild an API to interact with any website.
s2.devF25 · AIAPI for unlimited, durable, real-time streams
AgentMailS25 · AIEmail Inboxes for AI Agents
TesoraS25 · AIFrontier AI for Actuaries
HABITX25 · AIAccelerating world models.
ParsewiseX25 · AIMulti-document processing for your risk teams, AI agents, pipelines
BlindPayW25 · Developer toolsStablecoin API for global payments
Browser UseW25 · AIAgents that use the browser.
QuantstructW25 · AIAI documentation engineer – test & autoimprove stale product docs
ReJotW25 · DataWe turn complex API integrations into drop‑in full‑stack libraries
superglueW25 · AIconnect, migrate and implement enterprise systems
AbundantF24 · AIAgent simulation and RL for researchers
SurgeF24 · Developer toolsStripe for telephony
VespperF24 · AIThe best DOCX MCP for agents to edit microsoft word documents
OwayS24 · AIThe coordination OS for the physical economy.
PanoraS24 · AITurning messy inboxes into ERP-Ready Data
ScapeS24 · AIThe intelligent inbox that works for you
VideoGenS24 · AICreate professional videos in minutes with AI, online or via API
DownlinkW24 · AIMake your LLMs 3x faster.
FileforgeW24 · InactiveAPI For PDF Document Workflows
InteguruW24 · AIGenerate fast, reliable APIs for any platform
Magic HourW24 · AIAI media creation platform for creators and developers
PrecipW24 · AIHigh precision AI weather models
TesseralW24 · InactiveThe open source platform for managing identity in business software
TrieveW24 · AcquiredAll-in-one API for search, RAG, & recommendations
GlideS23 · AcquiredCrypto Deposits, Wallet Funding, and Pay-with-crypto Infra
InconvoS23 · AIBuild chat-with-data agents for customer-facing applications
MindedS23 · AICursor for AI Agents
MorphS23 · AIFast Models Optimized for Coding Agents
OpensteerS23 · AISpecialized agents for real work
RecipeUIS23 · Developer toolsThe open source Postman alternative.
SkyvernS23 · AIOpen Source AI Agent to automate browser workflows via an API
SmobiS23 · AISend texts your customers actually want over RCS
Sohar HealthS23 · AIAI-powered insurance verification to boost patient conversion.
TerminalS23 · Developer toolsPlaid for Telematics Data in Commercial Trucking
EscapeW23 · AIOffensive security for the teams that are 100x outnumbered
EzDubsW23 · AcquiredReal-time speech translation
FastgenW23 · Developer toolsWebflow for the Backend
FernW23 · AcquiredInstantly offer SDKs and API Docs
LaminateW23 · Developer tools
MercoaW23 · AIAI Agent for Billpay platforms to pay invoices with virtual cards
NangoW23 · Developer toolsA single API for all your integrations
PlayAIW23 · AcquiredOur mission is to make Voice AI accessible and useful to all.
PoplarMLW23 · AIDeploy Machine Learning Models with One Command
PropexoW23 · Developer toolsPlaid for Commercial Real Estate
SpecCheckW23 · Developer toolsUnifying how the optical industry does business.
SuperAPIW23 · Developer toolsProgrammable API gateway that makes APIs cacheable
TrigoW23 · AcquiredRent verification API for landlords and lenders
VersoriW23 · AcquiredAgentic integrations & automations for enterprise
AlteryaS22 · AcquiredProtecting Humans from Scams
AnchorS22 · Developer toolsEmbedded finance platform for African businesses
BridgecardS22 · InactiveCard issuer for Africa
Integration LabsS22 · InactiveThe Unified API for Business Financial Data
IntunedS22 · AICode-first scrapers and RPAs — built and maintained by AI
MetriportS22 · AIHealthcare data infrastructure for next generation care delivery.
MovingLakeS22 · DataRealtime Data Connectors
PayloadS22 · AcquiredDeveloper-First Headless CMS and Application Framework
PolyS22 · AIIntelligent Personal Cloud Storage
SunlightS22 · AIThe intelligence and execution layer for agentic B2B card payments.
TailorS22 · AIHeadless ERP for retail operations
TypewiseS22 · AICustomer service AI that resolves requests end-to-end.
VizzlyS22 · AcquiredCustomer-Facing Analytics for Modern SaaS.
AndiW22 · AIAI Search for the Next Generation
Dojah IncW22 · AIPrevent Fraud and Onboard Users Faster
EmobiW22 · AIA single point integration for secure and automated EV charging.
HyperbeamW22 · Developer toolsAPI for shared embeddable web browsers
KableW22 · InactiveUsage-based billing for API companies
Karate LabsW22 · Developer toolsOpen-source API & UI test automation
NyckelW22 · AIClassify Anything
PelmW22 · InactivePlaid for utilities
Prembly (formerly Identitypass)W22 · Developer toolsIdentity Verification API for Emerging Markets
RequestlyW22 · AcquiredOpen-Source Postman alternative
SendoW22 · InactiveThe best SMS/RCS API for startups
Serif HealthW22 · AIHealthcare Price Transparency APIs and Data Products
SnapTradeW22 · Developer toolsPlaid for trading
TheneoW22 · AIStripe-like API Docs in just a few clicks
ValariW22 · InactiveEmbedded finance platform for LatAm.
VesselW22 · InactiveDeveloper-first, native integration platform for GTM tools
WingbackW22 · InactiveWingback provides tools and APIs for SaaS pricing and packaging.
AnakinS21 · AIOne API to get clean data from any website for your AI agents at scale
Buró de IngresosS21 · Developer toolsThe Work Number for LatAm
CoastS21 · AIDemo Platform for API-First Companies
CumbucaS21 · Developer toolsBare-metal access to Brazil's Open Finance and Pix systems
Dots 💸S21 · Developer toolsDeveloper friendly drop in payouts infrastructure
PluggyS21 · Developer toolsPlaid for Brazil: we allow developers to access users' financial data
WarrantS21 · AcquiredAuthorization and access control as a service.
DyteW21 · AcquiredReal-time audio & video SDKs, ready to launch 🚀
EnodeW21 · Developer toolsEnergy Orchestration Platform
FlowEQW21 · Developer toolsNo-code workflow tool
GigsW21 · AIThe OS for Embedded Telecom
HUBUCW21 · Developer toolsGlobal Card Issuing and Payment Processing Engine
LogisticsOSW21 · Developer toolsWorld's fastest and most optimal route optimization engine
QuicknodeW21 · Developer toolsTools & infra to build and scale high-quality blockchain applications.
SvixW21 · Developer toolsEnterprise ready webhooks service, open-source and in the cloud
DecentroS20 · Developer toolsAPI Platform for Banking Integrations (Plaid for India and APAC)
FinchS20 · Developer toolsFinch is the Employment Data Platform
PhotoroomS20 · AIPower commerce photography with generative AI
SeamS20 · Developer toolsAPI for IoT Devices
VerifiableS20 · Developer toolsAPI for healthcare compliance
Carbon-12 LabsW20 · InactiveA Global Payouts API for Startups
HandoffW20 · AIAI estimator & agent for remodelers.
JunctionW20 · Developer toolsAPI for at-home health data
QuillW20 · DataFullstack API and management platform for dashboards and reporting
Recall.aiW20 · AIThe API to get recordings, transcripts, and metadata from meetings
WeavW20 · AcquiredWeav is the universal API for commerce platforms
Mipos.devS19 · InactiveApi that let you connect all the restaurant tech services in Latam
AlpacaW19 · Developer toolsAPI-first stock and crypto brokerage platform
BasilicaW19 · InactiveBasilica is an API that embeds high-dimensional data like images and…
CosmicW19 · AICosmic is an AI-powered headless CMS
UltralightW19 · Developer toolsUniversal, Pure-GPU HTML Renderer
VertoW19 · Developer toolsCross-Border Payments and FX Simplified
Alpha VantageS18 · AIDeveloper-friendly and enterprise-grade APIs for financial market…
DuffelS18 · Developer toolsThe complete toolkit to sell travel.
Modern TreasuryS18 · Developer toolsPayment operations tools for money movement.
OneGraphS18 · AcquiredGraphQL API to connect all of the internet's APIs. Join us at Netlify!
XkitS18 · InactiveUniversal CRM integration for B2B SaaS apps
Treasury PrimeW18 · Developer toolsEmbedded banking software platform and marketplace
AssemblyAIS17 · AIThe best way to build Voice AI apps
Ribbon HealthS17 · AcquiredHealth enterprise API for data on doctors, insurance, costs, & quality
OneFinW17 · Developer toolsShopify for Financial Services
Scaphold.ioW17 · AcquiredThe Universal API
Veryfi, Inc.W17 · AIDocument AI. One API Call.
BirdS16 · Developer toolsThe world’s largest omnichannel communications platform
Scanate/FellowS16 · InactiveAPI for Invoice FinancingUtilityScore (formerly Pando)S16 · InactiveAPI that estimates utility costs for 100M+ homes.
DeepgramW16 · AIBuilding foundational AI for speech transcription and understanding.
MuxW16 · Developer toolsVideo infrastructure for developers
MoltinW15 · AcquiredeCommerce building blocks through simple APIs for websites & apps.…
CheckrS14 · AIPeople infrastructure for the future of work
RickshawW14 · AcquiredSame day local delivery, via API. Currently operating in SF.
Standard TreasuryS13 · AcquiredBanking APIs; acquired by Silicon Valley Bank in August 2015
FramebaseS12 · InactiveAPI for video.
SlidePayW12 · AcquiredBanking and Payment Platform APIs. Exited October 2014.
DrChronoW11 · AcquiredThe essential platform for modern medical practices and patients.
FlotypeW11 · InactiveThird generation of web apps.
MailgunW11 · AcquiredEmail API service.
ZencoderW10 · AcquiredVideo Encoding API,
Open source video player (video.js)Not affiliated with Y Combinator. From YC's public directory. Logos via logo.dev; trademarks belong to their owners.