Y Combinator Developer tools companies
Infrastructure, testing, observability and anything a developer adopts before procurement notices. Distribution is often bottom-up, which changes the whole GTM calculus.
564 companies matched in the directory.
Showing the first 200 of 564. Search the full directory to filter further.
- MemorableYC Summer 2027· San Francisco, CA, USA· 2 people
reducing agent reasoning into a graph search problem
- LinzumiYC Spring 2026· San Francisco, CA, USA· 3 people
Team chat to command all your company's coding agents
- Waddle LabsYC Summer 2026· San Francisco, CA, USA· 2 people
LLMs that control robots
- Quotient LabsYC Winter 2026· San Francisco, CA, USA· 2 people
Use Claude Code at 47% less cost in one line of installation.
- RunAnywhereYC Winter 2026· San Francisco, CA, USA· 5 people
Fastest inference anywhere: open models on-prem, hosted or on-device
- /dev/fastYC Winter 2026· San Francisco, CA, USA· 4 people
/dev/fast is the AI-native code forge
- SkillsyncYC Winter 2026· San Francisco, CA, USA· 2 people
Notion for AI chats
- SalusYC Winter 2026· San Francisco, CA, USA· 2 people
Guardrails to validate your agent's actions before they execute
- IncidentFoxYC Winter 2026· San Francisco, CA, USA· 2 people
AI SRE agent that triages, coordinates, and fixes production incidents
- ArchalYC Summer 2026· San Francisco, CA, USA· 2 people
API sandboxes, built for AI agents
- SupersetYC Spring 2026· San Francisco, CA, USA· 4 people
Building self-improving software
- CorelayerYC Winter 2026· San Francisco, CA, USA· 3 people
AI production engineer for regulated industries
- InthYC Spring 2026· London, England, United Kingdom· 3 people
Monitor and fix product privacy issues before they block growth
- ReplicasYC Spring 2026· San Francisco, CA, USA· 2 people
Run any coding agent harness in the cloud
- ZenbuYC Spring 2026· San Francisco, CA, USA· 1 people
The browser for agentic development
- SuperlogYC Spring 2026· Paris, Île-de-France, France· 2 people
Make software self-healing
- Deep InteractionsYC Spring 2026· San Francisco, CA, USA· 6 people
Collaborative AI app builder for teams
- Keyframe LabsYC Spring 2026· Los Angeles, CA, USA· 2 people
Bring AI to life with the world's best interactive avatars
- Reason MachinesYC Spring 2026· San Francisco, CA, USA· 2 people
Reason Machines builds Reason Agent, the autonomous software engineer…
- MentlioYC Summer 2026· San Francisco, CA, USA· 0 people
Engineering Intelligence and Token Optimization for the AI-Coding Era
- InsForge (InstaCloud)YC Spring 2026· San Francisco, CA, USA· 6 people
The agent-native serverless cloud
- RindlerYC Summer 2026· Boston, MA, USA· 2 people
The IDE for Tokenmaxxers
- GitCafeYC Summer 2026· San Francisco, CA, USA· 1 people
The Git forge for the next hundred billion commits
- HopliteYC Summer 2026· San Francisco, CA, USA· 2 people
Effortlessly deploy cloud software factories.
- PrizedYC Summer 2026· San Francisco, CA, USA· 2 people
A cloud devbox that feels local
- SpekoYC Summer 2026· San Francisco, CA, USA· 4 people
OpenRouter for Voice AI: one API, every call on the best speech model
- JcodeYC Summer 2026· San Francisco, CA, USA· 1 people
High performance coding agents
- RiftenYC Summer 2026· San Francisco, CA, USA· 5 people
Earned intelligence for every company
- CodagYC Summer 2026· San Francisco, CA, USA· 1 people
The AI gateway for cheaper, faster, permissioned agents.
- Alkera AIYC Summer 2026· San Francisco, CA, USA· 3 people
Reliable and safe data engineering and data science agents
- Agency Tool CompanyYC Summer 2026· Denver, CO, USA· 3 people
Reliable infrastructure to build, deploy and manage real-world robots.
- machine0YC Summer 2026· San Francisco, CA, USA· 1 people
AWS for Agents
- Graphify LabsYC Summer 2026· San Francisco, CA, USA· 1 people
On-device Knowledge Graph engine for Enterprise Software
- HilstartYC Summer 2026· San Francisco, CA, USA· 0 people
Autonomous Hardware Testing
- InkboxYC Summer 2026· San Francisco, CA, USA· 3 people
The identity and communication layer for AI agents
- Agnost AIYC Summer 2026· San Francisco, CA, USA· 2 people
We find where AI agents fail, then train better models to run them.
- TokenlessYC Summer 2026· San Francisco, CA, USA· 3 people
We find flaws in RL environments and evals and help you fix them.
- HyperProbeYC Summer 2026· San Francisco, CA, USA· 8 people
AI engineer that debugs and fixes production incidents in realtime
- Autoresearch, Inc.YC Summer 2026· San Francisco, CA, USA· 3 people
Autoresearch as a service: we solve your hardest measurable problems
- hardware intelligenceYC Summer 2026· San Francisco, CA, USA· 2 people
AI tools for the chips your AI runs on
- SimanticYC Fall 2026· Waterloo, ON, Canada· 4 people
Firmware simulation for AI agents
- ConiferYC Summer 2026· San Francisco, CA, USA· 4 people
Least cost routing system to reduce 70%+ token spend
- herdrYC Fall 2026· Ankara, Ankara, Turkey· 1 people
building the open agent runtime
- Agent 37YC Fall 2026· New York City, NY, USA· 0 people
Persistent sandboxes for agents like hermes, openclaw, claude code
- BoatYC Fall 2026· Paris, Île-de-France, France· 3 people
The best cloud VMs for billions of agents
- MirrorsYC Fall 2026· San Francisco, CA, USA· 2 people
Give AI agents the right instructions at the right moment
- ByteAskYC Fall 2026· San Francisco, CA, USA· 2 people
The AI coding agent for C and C++
- Agent RelayYC Fall 2026· San Francisco, CA, USA· 2 people
The infrastructure to run coding agents for your team
- Workers IOYC Fall 2026· San Francisco, CA, USA· 2 people
Simulation Environments for Verifying Mission Critical Software
- RysticYC Fall 2026· San Francisco, CA, USA· 2 people
API simulators for testing and training agents locally
- UXDuckYC Fall 2026· San Francisco, CA, USA· 1 people
Android for drones
- ComposalYC Fall 2026· London, England, United Kingdom· 3 people
Swarms of agents acting like users to find bugs before release
- MaritimeYC Fall 2026· San Francisco, CA, USA· 3 people
The managed cloud for AI agents.
- Boxes.devYC Fall 2026· San Francisco, CA, USA· 2 people
Cloud development environments for AI coding
- OnlookYC Winter 2025· San Francisco, CA, USA· 4 people
The Developer tool for Designers
- QuantstructYC Winter 2025· San Francisco, CA, USA· 2 people
AI documentation engineer – test & autoimprove stale product docs
- PromptlessYC Winter 2025· San Francisco, CA, USA· 5 people
An AI teammate that automatically updates your customer-facing docs
- DextoYC Winter 2025· San Francisco, CA, USA· 2 people
AWS for AI Agents
- SublingualYC Winter 2025· San Francisco, CA, USA· 2 people
Daily productivity tracker
- a0.devYC Winter 2025· San Francisco, CA, USA· 3 people
We make mobile apps using AI.
- Lucidic AIYC Winter 2025· San Francisco, CA, USA
Reimagining how Machines Learn
- ReJotYC Winter 2025· Amsterdam, NH, Netherlands· 2 people
We turn complex API integrations into drop‑in full‑stack libraries
- Confident AIYC Winter 2025· San Francisco, CA, USA· 7 people
The LLM Eval and Observability Platform for AI Quality
- InfiniteYC Winter 2025· San Francisco, CA, USA· 4 people
Global B2B Stablecoin Processor
- MastraYC Winter 2025· San Francisco, CA, USA· 30 people
The Javascript framework for building AI agents, from the Gatsby devs
- CorsairYC Winter 2025· New York City, NY, USA· 2 people
OpenRouter for Integrations
- TensorPoolYC Winter 2025· San Francisco, CA, USA· 3 people
Vercel For GPUs
- CodevisorYC Winter 2025· San Francisco, CA, USA· 2 people
The fastest native app for agentic engineering.
- TrainLoopYC Winter 2025· San Francisco, CA, USA· 6 people
Reasoning Fine-Tuning
- assistant-uiYC Winter 2025· San Francisco, CA, USA· 3 people
Open Source React.js Library for AI Chat
- BlindPayYC Winter 2025· San Francisco, CA, USA· 9 people
Stablecoin API for global payments
- BlaxelYC Spring 2025· San Francisco, CA, USA· 12 people
The infrastructure for autonomous agents
- KashikoiYC Spring 2025· San Francisco, CA, USA· 2 people
Simulation Engine for Benchmarking AI Products
- GolfYC Spring 2025· San Francisco, CA, USA· 1 people
Agentic AI Security and Governance
- cubicYC Spring 2025· London, England, United Kingdom· 6 people
AI-powered code review platform
- CapacitiveYC Spring 2025· San Francisco, CA, USA· 2 people
The data gateway for agents.
- FeynYC Spring 2025· San Francisco, CA, USA· 3 people
Custom models trained on your data
- HelixDBYC Spring 2025· London, England, United Kingdom· 6 people
The fastest & most scalable graph-vector database on the market
- PercivalYC Spring 2025· San Francisco, CA, USA· 3 people
Accelerating data analysis for research
- AttuneYC Spring 2025· San Francisco, CA, USA· 3 people
Faster builds, zero effort.
- Better AuthYC Spring 2025· San Francisco, CA, USA· 4 people
The authentication framework for TypeScript
- TinfoilYC Spring 2025· San Francisco, CA, USA· 5 people
Encrypted AI with verifiable privacy
- ChironYC Spring 2025· London, England, United Kingdom· 2 people
Grammarly for Math ✏️
- ClideyYC Spring 2025· San Francisco, CA, USA· 5 people
Turn scattered data into one platform for decision-making
- PrismYC Spring 2025· San Francisco, CA, USA· 2 people
Abundant Intelligence for Everyone
- Human BehaviorYC Spring 2025· San Francisco, CA, USA· 3 people
Understand your users beyond the numbers
- ParaQueryYC Spring 2025· New York City, NY, USA· 1 people
Managed GPU-accelerated Spark + SQL at 2x speed and half the cost
- Cactus ComputeYC Summer 2025· San Francisco, CA, USA· 8 people
Automation Foundation Models For Tiny Devices
- MindFortYC Spring 2025· Los Angeles, CA, USA· 6 people
Autonomous Security Agents
- mlopYC Spring 2025· London, England, United Kingdom· 2 people
Experiment tracking for training ML models
- StarSlingYC Spring 2025· San Francisco, CA, USA· 3 people
Self-Driving CI: fast AI-native GitHub Actions runners
- DocketYC Spring 2025· San Francisco, CA, USA· 2 people
AI agents for web testing
- Dedalus LabsYC Summer 2025· San Francisco, CA, USA· 8 people
Persistent computers for AI agents
- TraceRoot.AIYC Summer 2025· San Francisco, CA, USA· 4 people
Open source self-improving layer for AI agents
- AgentMailYC Summer 2025· San Francisco, CA, USA· 10 people
Email Inboxes for AI Agents
- argsYC Summer 2025· New York City, NY, USA· 2 people
A better GItHub
- LarkYC Summer 2025· San Francisco, CA, USA· 5 people
The E2E testing layer for AI-driven development
- LotasYC Summer 2025· San Francisco, CA, USA· 2 people
AI for quantitative trading
- CyberdeskYC Summer 2025· San Francisco, CA, USA· 2 people
Self learning computer use agent for developers
- AlterYC Summer 2025· New York City, NY, USA· 2 people
Privileged Access Management for AI Agents
- ProliferateYC Summer 2025· San Francisco, CA, USA
Do your life's work with agents
- MagnitudeYC Summer 2025· San Francisco, CA, USA· 2 people
Run open models as fast as your hardware allows
- EmbedderYC Summer 2025· San Francisco, CA, USA· 6 people
Hardware-Aware AI for Embedded Software
- VibeFlowYC Summer 2025· San Francisco, CA, USA· 3 people
AI content manager that grows your company's online presence
- NozomioYC Summer 2025· San Francisco, CA, USA· 3 people
product lab. focused on personal ai and context.
- ManufactYC Summer 2025· ZH, Switzerland· 5 people
Cloud infrastructure for MCP servers and Claude / ChatGPT plugins.
- AutosanaYC Summer 2025· San Francisco, CA, USA· 5 people
AI agents for E2E testing across mobile & web
- OmnaraYC Summer 2025· San Francisco, CA, USA· 4 people
The Open-Source Alternative to Claude Managed Agents
- NotteYC Summer 2025· San Francisco, CA, USA· 5 people
Browser infra for AI agents: sessions, auth, proxies, payments
- KERNELYC Summer 2025· San Francisco, CA, USA· 22 people
Crazy fast, open source infra for AI agents to use the Internet
- OkibiYC Summer 2025· San Francisco, CA, USA· 2 people
Turns products into CLIs and agents into customers
- stagewiseYC Summer 2025· Remote· 2 people
The Open Source Agentic IDE
- ModelenceYC Summer 2025· San Francisco, CA, USA· 3 people
Production infrastructure on autopilot
- InterfereYC Summer 2025· New York City, NY, USA· 8 people
Give engineering, product, and design teams insight into unseen issues
- LuminalYC Summer 2025· San Francisco, CA, USA· 7 people
Making AI run fast on any hardware.
- ParseYC Fall 2025· San Francisco, CA, USA· 4 people
Build an API to interact with any website.
- The Context CompanyYC Fall 2025· San Francisco, CA, USA· 2 people
Find what's losing you customers and money in your AI agent and fix it
- dari.devYC Fall 2025· San Francisco, CA, USA· 2 people
The Routing Layer for AI Agents
- Kestrel AIYC Fall 2025· San Francisco, CA, USA· 2 people
AI Agents for Platform Engineering
- RovrYC Fall 2025· San Francisco, CA, USA· 3 people
AI FDE Engine that runs your engineering workflows
- CompyleYC Fall 2025· San Francisco, CA, USA· 2 people
The coding agent that actually collaborates with you
- RadiusYC Fall 2025· San Francisco, CA, USA· 2 people
Code and browse in the same place
- s2.devYC Fall 2025· San Francisco, CA, USA· 5 people
API for unlimited, durable, real-time streams
- SourcebotYC Fall 2025· San Francisco, CA, USA· 3 people
Helping humans and AI agents understand massive codebases
- SpecificYC Fall 2025· Stockholm, Stockholm County, Sweden· 2 people
The cloud platform built for coding agents
- LemmaYC Fall 2025· San Francisco, CA, USA· 2 people
Production Monitoring for AI agents
- FastshotYC Fall 2025· Thessaloniki, Greece· 3 people
Lovable for mobile apps
- MossYC Fall 2025· San Francisco, CA, USA· 5 people
Real-time semantic search for Conversational AI
- CoastsYC Fall 2025· Remote· 2 people
Localhost service isolation and orchestration for git worktrees
- Upsolve AIYC Winter 2024· Remote· 5 people
Deploy trustworthy data agent that know your business
- TesseralYC Winter 2024· San Francisco, CA, USA· 5 people
The open source platform for managing identity in business software
- Stitch TechnologiesYC Winter 2024· London, England, United Kingdom· 0 people
-
- GreptileYC Winter 2024· San Francisco, CA, USA· 35 people
AI code review agent with complete context of your codebase
- NuancedYC Winter 2024· San Francisco, CA, USA· 2 people
the AI coding app for thinking.
- MomenticYC Winter 2024· San Francisco, CA, USA· 18 people
Mo, the AI QA engineer that bug-bashes your app before every release
- nCompass TechnologiesYC Winter 2024· New York City, NY, USA· 3 people
Optimize performance on GPUs - 10x faster
- KeystrokeYC Winter 2024· Salt Lake City, UT, USA· 4 people
An all-in-one platform for building internal agents & workflows
- Agentic LabsYC Winter 2024· New York City, NY, USA· 2 people
AI system design tools for dev teams
- LeapingYC Winter 2024· New York City, NY, USA· 2 people
Automate bug resolution
- TuskYC Winter 2024· San Francisco, CA, USA· 4 people
AI agent that generates unit and integration tests
- CelestYC Winter 2024· San Francisco, CA, USA· 1 people
The Vercel of Flutter
- RespanYC Winter 2024· San Francisco, CA, USA· 23 people
Self-driving observability, evals, and gateway for AI agents
- PolishedYC Winter 2024· San Francisco, CA, USA
Generate ads. Iterate till perfect.
- Decipher AIYC Winter 2024· San Francisco, CA, USA· 4 people
QA agents that write tests 10x faster with zero maintenance
- ToolifyYC Winter 2024· Bengaluru, KA, India· 2 people
Build internal tools with AI
- Vibrant LabsYC Winter 2024· San Francisco, CA, USA· 6 people
Autonomously scaling environments
- PaziYC Winter 2024· Remote· 7 people
Platform where autonomous companies are built
- EllipsisYC Winter 2024· New York City, NY, USA· 2 people
Cloud platform for coding agents
- PreloopYC Winter 2024· Seattle, WA, USA· 2 people
Translate your experimental scripts into production ML services
- TrieveYC Winter 2024· San Francisco, CA, USA· 7 people
All-in-one API for search, RAG, & recommendations
- Centauri AIYC Winter 2024· San Francisco, CA, USA· 5 people
Helps teams work effectively with AI coding agents.
- Zep AIYC Winter 2024· San Francisco, CA, USA· 10 people
The unified context layer for enterprise data
- HatchetYC Winter 2024· New York City, NY, USA· 7 people
The orchestration platform for teams who ship.
- DownlinkYC Winter 2024· San Francisco, CA, USA· 1 people
Make your LLMs 3x faster.
- FileforgeYC Winter 2024· San Francisco, CA, USA· 3 people
API For PDF Document Workflows
- SilogyYC Winter 2024· New York City, NY, USA· 3 people
An AI-powered test and debug platform for chip developers
- SpurYC Summer 2024· New York City, NY, USA· 8 people
Spur is your AI QA Engineer. Test your websites with natural language.
- InteguruYC Winter 2024· San Francisco, CA, USA· 5 people
Generate fast, reliable APIs for any platform
- renderletYC Winter 2024· New York City, NY, USA· 2 people
Build interactive applications that run anywhere
- DragoneyeYC Winter 2024· New York City, NY, USA· 2 people
Custom video detection models in less than 5 minutes
- CovalYC Summer 2024· San Francisco, CA, USA· 10 people
Simulation & Evaluation that scales voice and chat AI agents
- MiruYC Summer 2024· San Francisco, CA, USA· 3 people
Config Management for Robotics
- DoublezeroYC Summer 2024· Remote· 2 people
Platform to build, use, and monetize fully autonomous agents
- VariantYC Fall 2024· San Francisco, CA, USA· 5 people
Creative intelligence
- Mem0YC Summer 2024· San Francisco, CA, USA· 10 people
The Memory layer for AI Agents
- Unsloth AIYC Summer 2024· San Francisco, CA, USA· 12 people
Open-Source Reinforcement Learning (RL) & Fine-tuning for LLMs.
- Random LabsYC Summer 2024· San Francisco, CA, USA
Random labs is building long running autonomous coding agents.
- InvariaYC Summer 2024· London, England, United Kingdom· 3 people
The next generation logging and observability platform
- PartyYC Summer 2024· San Francisco, CA, USA· 8 people
Secure multiplayer workspace for teams building with agents
- WordwareYC Summer 2024· San Francisco, CA, USA· 15 people
AI agents you can rely on
- ideate.xyzYC Summer 2024· London, England, United Kingdom· 2 people
ideate.xyz is an AI-powered 3D art suite on the web
- HyrexYC Summer 2024· San Francisco, CA, USA· 3 people
The COLD Task Framework
- CloudglueYC Summer 2024· San Francisco, CA, USA· 4 people
The video context layer for AI.
- Storia AIYC Summer 2024· San Francisco, CA, USA· 2 people
Open source AI copilot that knows your company's code and its context
- RunLocal AIYC Summer 2024· London, England, United Kingdom· 3 people
AI agent that optimizes inference for embedded compute like Jetson
- CodeVizYC Summer 2024· San Francisco, CA, USA· 2 people
One living model of your software architecture
- cmuxYC Summer 2024· San Francisco, CA, USA· 3 people
Open source applied AI lab building next-gen devtools
- expand.aiYC Summer 2024· San Francisco, CA, USA· 2 people
Turn any website into an API.
- VibeYC Summer 2024· San Francisco, CA, USA· 2 people
Making everyone a software engineer
- MagiCodeYC Summer 2024· San Francisco, CA, USA· 3 people
A Reliable AI Frontend Engineer
- OpslaneYC Summer 2024· San Francisco, CA, USA· 1 people
Verify AI-generated code before you ship it
- Thunder ComputeYC Summer 2024· San Francisco, CA, USA· 10 people
GPUs for Agents
- Ember RoboticsYC Summer 2024· San Francisco, CA, USA· 2 people
Datadog for robots
- PinnacleYC Summer 2024· San Francisco, CA, USA· 2 people
API & SDK for RCS (the next-generation of texting)
- LaminarYC Summer 2024· London, England, United Kingdom· 6 people
Understand why your AI agent breaks. Iterate fast to fix it.
- HaystackYC Summer 2024· New York City, NY, USA· 2 people
Replay real customer journeys against every change before you ship
- HeroUIYC Summer 2024· Buenos Aires, Buenos Aires, Argentina· 5 people
The UI framework for AI agents and developers to build beautiful apps.
- ZeroPathYC Summer 2024· San Francisco, CA, USA· 10 people
Automatically find and fix your software vulnerabilities
- VokerYC Summer 2024· Los Angeles, CA, USA· 6 people
The Agent Analytics Platform
- VoidYC Summer 2024· San Francisco, CA, USA· 2 people
The open source Cursor alternative
- FreestyleYC Summer 2024· San Francisco, CA, USA· 5 people
The most powerful sandboxes for AI Agents
- ConductorYC Summer 2024· San Francisco, CA, USA· 8 people
Run a team of coding agents on your Mac
- GaitYC Fall 2024· San Francisco, CA, USA· 2 people
Building Dev Infra for AI Software Engineers
- RevylYC Fall 2024· San Francisco, CA, USA· 16 people
The Mobile Development Platform
- VespperYC Fall 2024· San Francisco, CA, USA· 2 people
The best DOCX MCP for agents to edit microsoft word documents
- ArchilYC Fall 2024· San Francisco, CA, USA· 11 people
The high-performance file system that connects AI to data
- CekuraYC Fall 2024· San Francisco, CA, USA· 15 people
Voice AI and Chat AI agents: Testing and Observability
- EndstackYC Fall 2024· Los Angeles, CA, USA· 2 people
The complete, collaborative workspace for humans and agents
- FreebuffYC Fall 2024· San Francisco, CA, USA· 4 people
The free coding agent
- ChicoryYC Fall 2024· San Francisco, CA, USA· 2 people
The platform for automated hiring and workforce decisions.