Top accelerator startups

Startups14,448Programs29

14,448 startups · 29 programs

YC Open Source

182 companies · 128 active · 60% AI · most in W23 (21)

Companies tagged Open Source

AILuceboxSelf-improving inference workstationYC W27MilanStartup →AI0.securityThe autonomous cybersecurity teamYC F26San FranciscoStartup →AIAcyclic LabsAgent swarms that make long-running tasks exponentially fasterYC F26LondonStartup →AIAgent RelayLet your teams' coding agents message each otherYC F26San FranciscoStartup →AICavemanCaveman cuts what AI agents cost without making them dumber.YC F26AmsterdamStartup →Developer toolsEveryAppMaking every SaaS open sourceYC F26Startup →AILimnionTelemetry storage for the agentic era.YC F26SeattleStartup →AIPhone HarnessLet your agent control your phoneYC F26San FranciscoStartup →AITiloThe Microsoft of the AI era: the operating system for AI agents.YC F26San FranciscoStartup →AIGraphify LabsOn-device Knowledge Graph engine for Enterprise SoftwareYC S26San FranciscoStartup →AIOneCLIAI teammates for your business-critical work.YC S26Tel Aviv-YafoStartup →AIOneTrianglePrefill optimizations for the fastest inferenceYC S26San FranciscoStartup →AIOrchestraSelf-optimizing neocloud that cuts LLM costs by 100xYC S26San FranciscoStartup →AIRobocurveEvals for robotsYC S26San FranciscoStartup →AITracerCombining open-source AI models for better answers at lower costYC S26San FranciscoStartup →AISuperlogMake software self-healingYC X26ParisStartup →AIZenbuThe browser for agentic developmentYC X26San FranciscoStartup →AIRunAnywhereFastest inference anywhere: open models on-prem, hosted or on-deviceYC W26San FranciscoStartup →AIExpected ParrotSimulate your customers with AI agentsYC F25BostonStartup →AIs2.devAPI for unlimited, durable, real-time streamsYC F25San FranciscoStartup →AISourcebotHelping humans and AI agents understand massive codebasesYC F25San FranciscoStartup →AICactus ComputeAutomation Foundation Models For Tiny DevicesYC S25San FranciscoStartup →AICharThe AI notepad that knows and works for youYC S25SeoulStartup →AIEpicenterChatGPT's memory feature in an open, portable formatYC S25San FranciscoStartup →AIMagnitudeRun open models as fast as your hardware allowsYC S25San FranciscoStartup →AIManufactCloud infrastructure for MCP servers and Claude / ChatGPT plugins.YC S25San FranciscoStartup →Developer toolsModelenceProduction infrastructure on autopilotYC S25San FranciscoStartup →AIPangolinOpen networking and security for your workforce, AI agents, and infraYC S25New York CityStartup →AIstagewiseThe makers of Klex Bots, your own team of digital coworkers.YC S25Startup →AITraceRoot.AIThe open-source platform that continuously improves your ai agentsYC S25San FranciscoStartup →Developer toolsBetter AuthThe authentication framework for TypeScriptYC X25San FranciscoStartup →AICuaGive every agent a cloud desktopYC X25San FranciscoStartup →AIHelixDBThe fastest & most scalable graph-vector database on the marketYC X25LondonStartup →AIKaelioThe open-source context layer for data agentsYC X25Startup →AInao LabsOpen Source Analytics AgentYC X25ParisStartup →AIBrowser UseAgents that use the browser.YC W25San FranciscoStartup →AICodevisorThe fastest native app for agentic engineering.YC W25San FranciscoStartup →AIConfident AIProduction Monitoring & Evals for AI AgentsYC W25San FranciscoStartup →AICorsairOpenRouter for IntegrationsYC W25New York CityStartup →AIMastraThe Javascript framework for building AI agents, from the Gatsby devsYC W25San FranciscoStartup →AIMentraBuilding the open source smart glasses operating system.YC W25San FranciscoStartup →AIInactiveSublingualDaily productivity trackerYC W25San FranciscoStartup →AIcmuxOpen source applied AI lab building next-gen devtoolsYC S24San FranciscoStartup →AIDench.comWorkspace for your AI Agents, Build any Workflow.YC S24San FranciscoStartup →AIMem0The Memory layer for AI AgentsYC S24San FranciscoStartup →AIOpslaneAI Code Review tool that runs your appYC S24San FranciscoStartup →AIRandom LabsRandom labs is building long running autonomous coding agents.YC S24San FranciscoStartup →AIRowboat LabsOpen-source AI coworker with memoryYC S24BengaluruStartup →AIUnsloth AIOpen-Source Reinforcement Learning (RL) & Fine-tuning for LLMs.YC S24San FranciscoStartup →AIHatchetThe orchestration platform for teams who ship.YC W24New York CityStartup →AIInactiveLanternPostgres vector database extension to build AI applicationsYC W24San FranciscoStartup →AInCompass TechnologiesOptimize performance on GPUs - 10x fasterYC W24New York CityStartup →AIAcquiredOnyxOpen Source AI ChatYC W24San FranciscoStartup →AIPretzel AIAI toolingYC W24BerlinStartup →AISuperagentSecurity for AI-native developersYC W24San FranciscoStartup →AIInactiveTesseralThe open source platform for managing identity in business softwareYC W24San FranciscoStartup →AITracecatOpen-source agentic security automation platformYC W24New York CityStartup →AIAcquiredTrieveAll-in-one API for search, RAG, & recommendationsYC W24San FranciscoStartup →AIInactiveTuskAI agent that generates unit and integration testsYC W24San FranciscoStartup →AIVibrant LabsAutonomously scaling environmentsYC W24San FranciscoStartup →AIAcquiredFlowiseAIOpen source GenAI development platformYC S23RemoteStartup →AIHarnessRouterThe world's first unified interface for agent harnesses.YC S23San FranciscoStartup →AIKhojAI for humansYC S23San FranciscoStartup →AIAcquiredOpenPipeTurn expensive prompts into cheap fine-tuned modelsYC S23SeattleStartup →DataParadeDBYou should just use Postgres.YC S23San FranciscoStartup →DataAcquiredPeerDBFast, native ETL for Postgres 🐘 🚀YC S23Startup →Developer toolsRecipeUIThe open source Postman alternative.YC S23San FranciscoStartup →Developer toolsrefineOpen-source Retool for enterpriseYC S23San FranciscoStartup →AIReworkdThe simplest way to extract web data at scaleYC S23San FranciscoStartup →AISkyvernOpen Source AI Agent to automate browser workflows via an APIYC S23San FranciscoStartup →AITiptapThe open-source document editor for humans and AI agents.YC S23BerlinStartup →Developer toolsTwentyOpen Source CRMYC S23ParisStartup →AIwithHumanThe Approval Layer for AI AgentsYC S23LondonStartup →Developer toolsAcquiredArroyoCloud-native stream processingYC W23San FranciscoStartup →Developer toolsCommon PaperThe SAFE for commercial contractsYC W23PhiladelphiaStartup →AIAcquiredDAGWorks Inc.Open source tools & services for reliable AI Agents & AI ApplicationsYC W23San FranciscoStartup →AIAcquiredFernInstantly offer SDKs and API DocsYC W23New York CityStartup →AIAcquiredHeliconeLLM Observability for DevelopersYC W23San FranciscoStartup →Developer toolsAcquiredhighlight.ioThe open source, fullstack monitoring platform: stop guessing why…YC W23SeattleStartup →AIInfisicalSecurity infrastructure for developers and agentsYC W23San FranciscoStartup →Developer toolsAcquiredKeepThe open-source AIOps platformYC W23Tel Aviv-YafoStartup →AIAcquiredLangfuseOpen source LLM engineering platformYC W23BerlinStartup →AILiteLLMCall every LLM API like it's OpenAI [100+ LLMs]YC W23San FranciscoStartup →DataMatanoCloud Native SIEM (alternative to Splunk/Elastic)YC W23SeattleStartup →Developer toolsInactivemoonrepoOpen source build tool for monorepos and large codebasesYC W23PortlandStartup →Developer toolsNangoA single API for all your integrationsYC W23San FranciscoStartup →AIAcquiredOpenIntOpen Source Embedded Product IntegrationsYC W23RemoteStartup →AIReflexBuild the software you wish existed.YC W23San FranciscoStartup →AIRivetThe orchestrator for agentic workloads.YC W23San FranciscoStartup →Developer toolsTecladaRemote Shell Access in the BrowserYC W23San FranciscoStartup →AIAcquiredTraceloopKnow what your LLM is doing, and why it’s failingYC W23Tel Aviv-YafoStartup →AITrigger.devBuild and deploy fully‑managed AI agents and workflowsYC W23LondonStartup →AIUnifyModels that keep learningYC W23LondonStartup →AIAcquiredVocodeOpen source Voice AIYC W23San FranciscoStartup →AIActivepiecesOpen-source, AI-first and no-code business automation toolYC S22San FranciscoStartup →AIAnythingLLMThe open-source AI platform enterprises run on their own hardwareYC S22Los AngelesStartup →Developer toolsInactiveDittofeedOpen-source customer engagement & messaging automationYC S22Los AngelesStartup →AIFirecrawlBuilding the library for superintelligence.YC S22San FranciscoStartup →AIInactiveGraiOpen source version control for metadataYC S22San FranciscoStartup →Developer toolsAcquiredHyperDXOpen-source, dev-friendly observability.YC S22San FranciscoStartup →
Company
LuceboxSelf-improving inference workstationteam of 2hiringYC W27ActiveAI, Devtools
0.securityThe autonomous cybersecurity teamteam of 2YC F26ActiveAI, Devtools
Acyclic LabsAgent swarms that make long-running tasks exponentially fasterteam of 2YC F26ActiveAI, Devtools
Agent RelayLet your teams' coding agents message each otherteam of 2YC F26ActiveAI, Devtools
CavemanCaveman cuts what AI agents cost without making them dumber.YC F26ActiveAI, Devtools
EveryAppMaking every SaaS open sourceteam of 2YC F26ActiveDevtools
LimnionTelemetry storage for the agentic era.team of 3YC F26ActiveAI, Data, Devtools
Phone HarnessLet your agent control your phoneYC F26ActiveAI, Devtools
TiloThe Microsoft of the AI era: the operating system for AI agents.team of 2YC F26ActiveAI, Devtools
Graphify LabsOn-device Knowledge Graph engine for Enterprise SoftwareYC S26ActiveAI, Devtools
OneCLIAI teammates for your business-critical work.YC S26ActiveAI, Devtools
OneTrianglePrefill optimizations for the fastest inferenceteam of 4YC S26ActiveAI, Devtools
OrchestraSelf-optimizing neocloud that cuts LLM costs by 100xteam of 2YC S26ActiveAI, Devtools
RobocurveEvals for robotsteam of 3YC S26ActiveAI, Devtools
TracerCombining open-source AI models for better answers at lower costYC S26ActiveAI, Devtools
SuperlogMake software self-healingteam of 2YC X26ActiveAI, Devtools
ZenbuThe browser for agentic developmentYC X26ActiveAI, Devtools
RunAnywhereFastest inference anywhere: open models on-prem, hosted or on-deviceteam of 5hiringYC W26ActiveAI, Devtools
Expected ParrotSimulate your customers with AI agentsteam of 5YC F25ActiveAI, Devtools
s2.devAPI for unlimited, durable, real-time streamsteam of 5YC F25ActiveAI, Data, Devtools
SourcebotHelping humans and AI agents understand massive codebasesteam of 3hiringYC F25ActiveAI, Devtools
Cactus ComputeAutomation Foundation Models For Tiny Devicesteam of 8YC S25ActiveAI, Devtools
CharThe AI notepad that knows and works for youteam of 3YC S25ActiveAI, Devtools
EpicenterChatGPT's memory feature in an open, portable formatYC S25ActiveAI, Devtools
MagnitudeRun open models as fast as your hardware allowsteam of 2YC S25ActiveAI, Devtools
ManufactCloud infrastructure for MCP servers and Claude / ChatGPT plugins.team of 5hiringYC S25ActiveAI, Devtools
ModelenceProduction infrastructure on autopilotteam of 3YC S25ActiveDevtools
PangolinOpen networking and security for your workforce, AI agents, and infrateam of 3hiringYC S25ActiveAI, Devtools
stagewiseThe makers of Klex Bots, your own team of digital coworkers.team of 3YC S25ActiveAI, Devtools
TraceRoot.AIThe open-source platform that continuously improves your ai agentsteam of 4hiringYC S25ActiveAI, Devtools
Better AuthThe authentication framework for TypeScriptteam of 4YC X25ActiveDevtools
CuaGive every agent a cloud desktopteam of 3hiringYC X25ActiveAI, Devtools
HelixDBThe fastest & most scalable graph-vector database on the marketteam of 6YC X25ActiveAI, Data, Devtools
KaelioThe open-source context layer for data agentsteam of 8YC X25ActiveAI, Devtools
nao LabsOpen Source Analytics Agentteam of 2YC X25ActiveAI, Data, Devtools
Browser UseAgents that use the browser.team of 5hiringYC W25ActiveAI, Devtools
CodevisorThe fastest native app for agentic engineering.team of 2YC W25ActiveAI, Devtools
Confident AIProduction Monitoring & Evals for AI Agentsteam of 7hiringYC W25ActiveAI, Devtools
CorsairOpenRouter for Integrationsteam of 2YC W25ActiveAI, Devtools
MastraThe Javascript framework for building AI agents, from the Gatsby devsteam of 30YC W25ActiveAI, Devtools
MentraBuilding the open source smart glasses operating system.team of 12YC W25ActiveAI, Devtools
SublingualDaily productivity trackerteam of 2YC W25InactiveAI, Devtools
cmuxOpen source applied AI lab building next-gen devtoolsteam of 3hiringYC S24ActiveAI, Devtools
Dench.comWorkspace for your AI Agents, Build any Workflow.team of 6hiringYC S24ActiveAI, Devtools
Mem0The Memory layer for AI Agentsteam of 10hiringYC S24ActiveAI, Devtools
OpslaneAI Code Review tool that runs your appYC S24ActiveAI, Devtools
Random LabsRandom labs is building long running autonomous coding agents.YC S24ActiveAI, Devtools
Rowboat LabsOpen-source AI coworker with memoryteam of 3YC S24ActiveAI, Devtools
Unsloth AIOpen-Source Reinforcement Learning (RL) & Fine-tuning for LLMs.team of 12hiringYC S24ActiveAI, Devtools
HatchetThe orchestration platform for teams who ship.team of 7YC W24ActiveAI, Devtools
LanternPostgres vector database extension to build AI applicationsteam of 3YC W24InactiveAI, Data, Devtools
nCompass TechnologiesOptimize performance on GPUs - 10x fasterteam of 3YC W24ActiveAI, Devtools
OnyxOpen Source AI Chat32.2k starsteam of 20YC W24AcquiredAI, Data, Devtools
Pretzel AIAI toolingteam of 2YC W24ActiveAI, Devtools
SuperagentSecurity for AI-native developersteam of 2YC W24ActiveAI, Devtools
TesseralThe open source platform for managing identity in business softwareteam of 5YC W24InactiveAI, Devtools
TracecatOpen-source agentic security automation platformhiringYC W24ActiveAI, Devtools
TrieveAll-in-one API for search, RAG, & recommendationsteam of 7acquiredYC W24AcquiredAI, Data, Devtools
TuskAI agent that generates unit and integration teststeam of 4YC W24InactiveAI, Devtools
Vibrant LabsAutonomously scaling environmentsteam of 6YC W24ActiveAI, Devtools
FlowiseAIOpen source GenAI development platform55.5k starsteam of 5YC S23AcquiredAI, Devtools
HarnessRouterThe world's first unified interface for agent harnesses.team of 3YC S23ActiveAI, Devtools
KhojAI for humans37.5k starsteam of 2YC S23ActiveAI, Devtools
OpenPipeTurn expensive prompts into cheap fine-tuned modelsacquired by CoreWeaveteam of 2YC S23AcquiredAI, Devtools
ParadeDBYou should just use Postgres.team of 11hiringYC S23ActiveData, Devtools
PeerDBFast, native ETL for Postgres 🐘 🚀acquiredteam of 2YC S23AcquiredData, Devtools
RecipeUIThe open source Postman alternative.team of 2YC S23ActiveDevtools
refineOpen-source Retool for enterpriseteam of 10YC S23ActiveDevtools
ReworkdThe simplest way to extract web data at scale2 programsYC S23 +1ActiveAI, Devtools
SkyvernOpen Source AI Agent to automate browser workflows via an APIteam of 11hiringYC S23ActiveAI, Devtools
TiptapThe open-source document editor for humans and AI agents.team of 20YC S23ActiveAI, Devtools
TwentyOpen Source CRMteam of 11hiringYC S23ActiveDevtools
withHumanThe Approval Layer for AI Agentsteam of 2YC S23ActiveAI, Devtools
ArroyoCloud-native stream processingacquiredteam of 2YC W23AcquiredDevtools
Common PaperThe SAFE for commercial contractsteam of 8YC W23ActiveDevtools
DAGWorks Inc.Open source tools & services for reliable AI Agents & AI Applicationsacquiredteam of 2YC W23AcquiredAI, Devtools
FernInstantly offer SDKs and API Docsteam of 30acquiredYC W23AcquiredAI, Devtools
HeliconeLLM Observability for Developersteam of 5acquiredYC W23AcquiredAI, Data, Devtools
highlight.ioThe open source, fullstack monitoring platform: stop guessing why…team of 8acquiredYC W23AcquiredDevtools
InfisicalSecurity infrastructure for developers and agentsteam of 70hiringYC W23ActiveAI, Devtools
KeepThe open-source AIOps platformteam of 5acquiredYC W23AcquiredDevtools
LangfuseOpen source LLM engineering platformteam of 26acquired by ClickHouseYC W23AcquiredAI, Data, Devtools
LiteLLMCall every LLM API like it's OpenAI [100+ LLMs]59.6k starsteam of 20YC W23ActiveAI, Devtools
MatanoCloud Native SIEM (alternative to Splunk/Elastic)team of 2YC W23ActiveData, Devtools
moonrepoOpen source build tool for monorepos and large codebasesteam of 2YC W23InactiveDevtools
NangoA single API for all your integrationsteam of 6hiringYC W23ActiveDevtools
OpenIntOpen Source Embedded Product Integrationsacquiredteam of 4YC W23AcquiredAI, Data, Devtools
ReflexBuild the software you wish existed.team of 15hiringYC W23ActiveAI, Devtools
RivetThe orchestrator for agentic workloads.team of 7hiringYC W23ActiveAI, Devtools
TecladaRemote Shell Access in the BrowserYC W23ActiveDevtools
TraceloopKnow what your LLM is doing, and why it’s failingteam of 9acquiredYC W23AcquiredAI, Devtools
Trigger.devBuild and deploy fully‑managed AI agents and workflowsteam of 17YC W23ActiveAI, Devtools
UnifyModels that keep learningteam of 3YC W23ActiveAI, Devtools
VocodeOpen source Voice AIacquiredteam of 3YC W23AcquiredAI, Devtools
ActivepiecesOpen-source, AI-first and no-code business automation tool24.7k starsteam of 10YC S22ActiveAI, Devtools
AnythingLLMThe open-source AI platform enterprises run on their own hardwareteam of 4YC S22ActiveAI, Devtools
DittofeedOpen-source customer engagement & messaging automationteam of 2YC S22InactiveDevtools
FirecrawlBuilding the library for superintelligence.on 4 Glyph sourcesteam of 3YC S22ActiveAI, Devtools
GraiOpen source version control for metadatateam of 3YC S22InactiveAI, Data, Devtools
HyperDXOpen-source, dev-friendly observability.acquiredteam of 4YC S22AcquiredDevtools

About Open Source

Companies per batch

Open Source companies per YC batch
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Nearby spaces: Developer Tools 111, Infrastructure 22, Data Engineering 15, Generative AI 14, Analytics 14, API 13, Databases 10, Machine Learning 9, Security 9, DevSecOps 9