Developer Tools Startups funded by Y Combinator (YC) in the San Francisco Bay Area that are currently hiring 2025

Since graduating from YC, Amplitude (W12) has made it to IPO and beyond by helping cutting edge startups become category leaders. We’ve pioneered the digital analytics category to become the go-to solution for AI pioneers (Cruise, Midjourney), apps that touch millions of consumers (Doordash, Coinbase), and the best in B2B (Atlassian, Rippling, Canva). With product analytics, experiment, CDP, session replay, and more, Amplitude’s digital analytics platform shows you what your users love, where they’re getting stuck, and what keeps them coming back. You want to build a generational business, and we have the capabilities and pricing plans to guide you every step of the way. Check out our special deal for YC companies and get started on your analytics journey.

Dedalus Labs is building Vercel for AI Agents. We host MCP servers on our cloud and handle the boring stuff like autoscaling and load balancing so users can go from idea to production in a single click. Our OpenAI-compatible SDK lets users orchestrate complex agentic workflows through one clean API. Route between any LLM provider, connect any MCP tools from our hosted marketplace, and ship in minutes.

Embedder is a coding agent that can write, test, and debug firmware on both physical and simulated hardware. Supporting 20+ MCU/SoC platforms, it accelerates embedded systems development across semiconductors, automotive, medical devices, aerospace, IoT, and consumer electronics.

AgentMail is the email inbox API for AI agents. It gives agents their own email inboxes, like Gmail does for humans.

StarSling is building an agentic developer homepage that automates all the tasks that eat up a developer’s time after they’ve left their code editor: deployments, performance, incidents, and bugs. Open your homepage, click on a GitHub, Linear, or Sentry issue and you’ll see an Autofix button that triggers an AI agent and opens up a Pull Request with a fix, all without leaving your homepage.

Attune makes blazingly fast build tools that require zero migration effort. As AI enables developers to write code faster than ever, slow builds are increasingly becoming the bottleneck in development velocity. Developers regularly lose hours of productivity every day waiting for their builds. Imagine being able to write code in 1 minute, but needing to wait 30 minutes to compile, deploy, and test it. Existing solutions either require painful migrations to new tools (e.g. Bazel) or rely on just using bigger servers to run your builds. Instead, we do native, first-class integrations into compilers and build systems. With Attune, you don't need to integrate a new tool. Just make a one-line change from `cargo build` to `hurry cargo build` for 20x faster builds. Eliza (ex-Google) and Xin worked together for 3 years at FOSSA, where Eliza was Head of Engineering and Xin was Head of Product. Eliza brings a decade of programming languages and build systems expertise, while Xin brings a decade of experience building developer tools products, most recently as VP of Product at Teleport (S15). Having experienced the pain of slow builds firsthand across hundreds of production codebases, we're building the solution we've always wanted.

Better Auth is a comprehensive authentication framework for TypeScript that lets you implement everything from simple auth flows to enterprise-grade systems directly on your own database, embedded in your backend. It’s loved by developers all over the world and endorsed by leading voices in the ecosystem. On top of the framework, Better Auth also provides an infrastructure layer to help you scale with user management and analytics, bot and fraud detection, transactional email and SMS, global session storage and more.

Olive connects to your database & third party services to help you build admin dashboards and support tools in minutes.

Infinite is a stablecoin payment processor. We offer businesses turnkey APIs and SDKs to instantly move money anywhere in the world at a fraction of the cost of traditional solutions.

Onlook is the fastest way for anyone to build, deploy, and iterate on websites and web apps. We built an open-source, visual editor for code that merges design, development, and AI. Since launching, Onlook hit #1 on Hacker News, was the #1 trending repo on GitHub—above DeepSeek—and has earned over 8,500 GitHub stars. Founded by Daniel Farrell, a designer of 10+ years and former Head of Growth, and Kiet Ho, an ex-Amazon and ex-ServiceNow engineer, Onlook is on a mission to finally solve the gap between design and development.

a0.dev is a platform that helps mobile developers build high quality apps in days instead of weeks by generating custom react native projects. We've launched top ranking apps that have been used by hundreds of thousands, and now we're creating the tools we wish we had to build faster.

Confident AI allows companies of all sizes to benchmark, safeguard, and improve LLM applications, with best-in-class metrics and guardrails powered by DeepEval. Built by the creators of DeepEval (4.3k stars, >400k monthly downloads), Confident AI is able to offer battle-tested, open-source evaluation algorithms while providing the infrastructure needed for teams to stay confident their LLM systems.

Quantstruct automatically creates and improves product documentation, implementation guides, and changelogs for API & SDK products, web-based enterprise software, and internal applications. Quantstruct identifies gaps in your knowledge base based on each product release or unfulfilled customer query. It uses multiple AI agents to search existing knowledge sources, test existing docs for validity and style guidelines, and clicks, scrolls, and uses enterprise software through a web browser to generate docs with embedded screenshots and video recordings. Quanstruct is available as a cloud service to start, targeting technical writers, content writing, professional services, and product teams. Traditional generative AI tools risk hallucinating critical API & SDK fields, even with RAG based approaches. Purely agent-based approaches risk providing unpredictable output that can diverge from desired documentation processes. Finally, no company’s review and publishing workflow is the same. Quantstruct is the easiest way to onboard and customize AI agents to continuously improve your documentation based on your customer needs and product evolution. https://quantstruct.com

Docs are integral to a great customer experience, but managing them is a challenging, multi-team effort. The most successful companies recognize that fantastic docs drive adoption and bad ones cause customers to churn. Promptless is used by fast-growing startups and Fortune 500 enterprises alike to automatically update docs based on feature releases, support tickets, internal Slack conversations, and more. Promptless is designed to be flexible—it can integrate with any docs platform, be triggered automatically from many workflows, and can pull in context from any internal knowledge source. With Promptless, documentation becomes a strategic advantage for growth, not a bottleneck or a liability.

Creative intelligence

Ryvn provides the devtools and infrastructure to easily deploy any workload, on any cloud, and on-prem. Run apps in your own cloud and offer Bring Your Own Cloud (BYOC) to your customers in minutes, with built-in observability designed for sensitive industries.

Revyl is a AI-native mobile testing platform that automatically catches and triages bugs before they reach production.

CodeLayer is an OSS IDE for managing coding agents, built with proven workflows to solve hard problems in complex codebases.

Unsloth helps builders create custom models better & faster using RL and custom kernels. We're developing the all in one solution to help you create highly-accurate custom models 30x faster with 90% less memory use. With over 10 million monthly model downloads and 40K GitHub stars, our mission is to make training and open-source the best it can be!

Run parallel agents in isolated workspaces. See at a glance what they’re working on, then review and merge their changes.

Never code up another test or hire an external QA team. We handle and automate all functional and E2E testing.

Self-serve GPUs in VS Code with persistent storage, snapshots, and hot-swappable hardware, with prices 80% lower than AWS.

Cloudglue APIs (https://cloudglue.dev) makes it easy to transform video and audio into structured data for your LLM/RAG/AI application. Our developer-friendly APIs makes it easy to integrate video chat into your AI assistant with minimal heavy-lifting.

ZeroPath is a developer tool that autonomously detects, verifies, and submits fixes for vulnerabilities in your code. Engineers can use ZeroPath to find security problems that they might only otherwise catch in pentests or from bug bounty researchers.

Mem0 provides a memory layer for LLM applications, enabling them to remember and learn from user interactions over time.

AI Agents have arrived. They are powerful enough to read, plan, and act across your everyday life and work. The question is no longer whether they can run canned demos to check the weather, it’s whether real teams can rely on them for critical work. We optimize for adoption over spectacle: useful, accountable systems that help top professional complete real tasks. Wordware is backed by Spark Capital, Felicis, and Y Combinator, with a $30M seed round. Our beautiful, historic San Francisco office sits in the shadow of the Golden Gate Bridge, it’s full of plants and radiates innovation and calm. We genuinely love working together. At lunch we talk about alignment and AI consciousness, we have surfboards in the office ready to use, we take walking meetings on the beach and hang out after work at the bar or climbing wall. We work really hard because we care deeply about what we do. Sauna is Wordware’s AI workspace for professionals. Think ‘Cursor for Knowledge Work’ and you’re halfway there. With explicit permission, it connects to tools like Gmail, Calendar, Slack, and thousands more, to gather the right context to move your work forward. It learns who you are, drafts and refines your documents, presentations, and datasets, researches across the web and your org’s internal knowledge, summarizes long threads to cut through the noise, proposes next steps, even acts on your behalf when enabled. You can work with Sauna live, side-by-side, or schedule jobs to run automatically in the background, with clear permissions and easy off-switches. Sauna brings the power of AI Agents to all professionals.

Decipher learns from session replays and writes reliable tests that prevent regressions on all your product flows. Plus get alerted when a bug hits production users.

Ocular AI is the data annotation engine for Generative AI, Computer Vision, and Enterprise AI models. We help you transform unstructured, multi-modal data into golden datasets to power generative AI, frontier models, and computer vision. Ocular Foundry is the most intuitive, data-centric, and fastest platform that lets you label, annotate, version, and deploy your data for training models. It also orchestrates your annotation jobs, improving collaboration with members and annotators. With Ocular Bolt, shift from humans in the loop to experts in the loop to supercharge your data labeling and annotation projects. Our global expert workforce ensures fast, accurate results—no matter the scale or complexity of your data. Companies spend huge amounts on training data, but Foundry and Bolt are AI-native tools that lower costs, reduce manual effort, and accelerate high-quality data collection. We’re replacing outdated, clunky, and expensive data software!

14.ai is a Zendesk alternative built from the ground up for AI agents. The Cursor for customer support.

Greptile reviews pull requests with full context of the codebase. Top YC companies like PostHog, Raycast, Vouch, Podium, and YC's own internal software team use Greptile to review millions of changes every week. When companies start using Greptile, they catch more bugs and merge PRs 4x faster, on average Greptile can be used via the cloud, or be hosted 100% on your cloud in an air-gapped VPC.

Silimate is the copilot for chip designers; it finds and fixes functional and PPA issues in your chip designs. Today, chip teams spend most of their 12-18 month design cycles converging slowly to functional correctness and their targeted PPA (power/performance/area). With Silimate, chip designers create correct, PPA-converged RTL code in minutes and eliminate months from their tape out schedule.

Continue enables developers to ship faster with Continuous AI. The future of coding isn't writing more code. It's delegating the boring parts, so you can build the interesting stuff. Developers are drowning in AI-generated code. Continuous AI solves this by automating the workflows around code, not just the code itself. The role of the software engineer is shifting from prompting AI to designing processes that run automatically. With hundreds of thousands of users, Continue is loved by developers worldwide at organizations ranging from small startups to Fortune 500 companies. Continue has raised $5.1M from Heavybit, Y Combinator, and angel investors. The company was founded in 2023 and is based in San Francisco. We believe the time is now to create a future where developers are amplified, not automated.

Edit Files at 10500+ tok/sec. The other models you need to build the best coding agents that are fast, reliable, and cheap.

Waldium is an AI-driven platform for researching, writing, and publishing technical knowledge in formats that both humans and AIs can understand. We help developers create technical guides, resources and tutorials — structured, durable knowledge that AIs can learn from, cite, and build upon.

Corgea helps engineers ship code and not vulnerabilities. It's an AI-powered SAST, unlike traditional SAST with tons of false positives, Corgea can find vulnerabilities like business logic flaws, API vulnerabilities, and broken authentication with little false positives (<5%). It also writes security fixes for engineers to approve.

Use your favorite JetBrains IDE without compromising on AI. Sweep is the best autocomplete and agent in JetBrains: https://plugins.jetbrains.com/plugin/26860-sweep-ai

Artie is software that streams data from databases to data warehouses in real-time. Today, most companies run their ETL process every few hours or overnight, so their data warehouse is always out of date; with Artie, the warehouse always has live production data.

Omnistrate is a cloud platform to SaaS-ify your docker image in minutes instead of years. Let’s say you have an open-source software, and you want to monetize your invention by building a multi-cloud SaaS solution. You can either spend years doing it yourself or use Omnistrate to do it in no time. Get started today by simply importing your existing docker-compose.

Traditional automation software is slow and expensive, Automat is 10X faster and 1/10th the price. It lets operations teams automate using video and natural language. 🧐 The problem: Traditional Robotic Process Automation is slow and expensive. 💡 Our Solution: Automat makes it 10X cheaper and faster to build any robotic process automation using natural language on any operating system We’re solving this by creating a platform that enables robotics process automation for Chrome using large language models and computer vision. Currently our customers send us descriptions or videos of the processes they’d like us to automate and we use our internal tooling to quickly build out those automations.

Companies struggle to customize their generative AI models by taking advantage of their existing customer and enterprise data, in real-time. Chima solves for this through a sleek, interoperable layer before the standard generative AI models are applied.

Helicone.ai is creating an advanced observability platform tailored for developers working with Large Language Models (LLMs). Our goal is to simplify and enhance the operational side of deploying these models, making it easier for developers to monitor, manage, and optimize their AI applications at scale. Helicone provides a unified view of performance, cost, and user interaction metrics for various LLM providers, like OpenAI, Anthropic, and LangChain, empowering developers to make their LLM deployments more efficient, reliable, and cost-effective. ### Key Features 1. **Centralized Observability**: Our platform captures and visualizes detailed logs and metrics across all LLM deployments. With tools for prompt management, performance tracing, and debugging, Helicone provides real-time insights into the inner workings of your LLMs. 2. **LLM Performance Optimization**: Helicone supports prompt experimentation, success rate tracking, and fine-tuning, allowing you to continuously improve response quality and efficiency. This level of insight makes it easier to deliver high-performing, cost-effective AI applications. 3. **Flexible Data Management**: We understand that data privacy is critical. Helicone supports deployment options for dedicated instances, hybrid cloud integrations, or self-hosted environments, allowing clients to maintain control over their data and ensuring compliance with privacy standards. ### Built for Developers and Data Scientists Helicone is designed to meet the needs of engineers and data scientists who require transparency and control over their LLMs. From chatbots to document processing systems, Helicone equips you with the insights needed to track costs, understand user interactions, and optimize outputs—all from one intuitive platform. By combining observability with LLM-specific insights, Helicone is redefining AI monitoring, empowering developers to deploy and scale their AI models with confidence.

Reflex is an AI app builder for creating production-grade web apps entirely in Python, powered by its own open-source framework. Python is one of the most popular programming languages in the world, and web development is one of the most popular applications of programming. So why can’t we make full-stack web apps using just Python? With Reflex, you just connect your data and enter a prompt. It generates production-ready apps that integrate any data source, API, or Python package. Founded by Nikhil Rao and Alek Petuskey, Reflex has over 1 million apps created, 27k GitHub stars, and has been used by 30% of Fortune 500 companies for internal tools and data-driven applications.

Infisical is the leading open-source platform to manage secrets, certificates, configs, and access across your team and infrastructure. Infisical stores your secrets and injects them back into your development workflow, CI/CD pipelines, and cloud infrastructure. It comes with secrets versioning, point-in-time recovery, audit logging, automatic secret rotation capabilities, and more.

We’re building an API for launching credit products. We enable companies to compliantly offer credit by handling the tech stack for origination, underwriting and loan management with just a few lines of code. We have built-in compliance guardrails to ensure that our customers comply with state and federal regulations and assist with licensing requirements and license management.

Cosine is a fully agentic SWE that allows you to instantly work on every single ticket at once, asynchronously.

Customers expect your SaaS to integrate with all the software they use. With Nango, you ship integrations your customers love, fast. Leverage hundreds of pre-built integrations and unlimited customization.

Firecrawl is a web data infrastructure platform that converts websites into clean, structured data optimized for AI applications through a simple API. Originally built as an internal tool at Mendable to solve their own data ingestion challenges, the team recognized the broader need for reliable web data extraction and transformed it into a standalone product. The platform combines web search, scraping, and AI-powered parsing into a unified solution, focusing on the core developer priorities of reliability, speed, and ease of use. By abstracting away the complexities of web data extraction, Firecrawl serves as the foundational data layer that enables AI applications to seamlessly access and process web content in the exact format they need.

Medplum makes it easy to build healthcare webapps that are compliant and interoperability ready. Our open source toolkit allows healthcare providers write apps that are HIPAA compliant, SOC2 certified and FHIR native - streamlining payor connections, health system integrations and more.

Taro is a community of 150k+ software engineers looking to grow their careers. High-growth tech companies leverage the Taro platform to hire engineers who can grow the company. Taro's education platform offers online courses and discussions with leaders at top tech companies. These resources attract many top engineers seeking their next career move. Taro supports the hiring process at startups through sourcing and feedback on engineers. If you're looking to expand your engineering team quickly, without compromising on quality, book time here: https://www.jointaro.com/enterprise/

Our mission is to make the web more collaborative. We're not just making collaboration faster—we're crafting it to be the best. Today we’re all using online platforms more than ever before - building, researching, learning, connecting etc. And we're not doing it alone. We're doing it together with other people and machines, turning the internet into the world's biggest team. Yet, the web was built for solo voyages. We saw a shift when platforms like Figma and Google Docs brought a multiplayer approach, breaking down walls and inspiring seamless teamwork. At Velt, we're taking it further. We're on a mission to infuse the magic of collaboration into the fabric of the web—one app at a time. We aim to erase the lines between online and offline co-working, crafting an environment where distance is irrelevant, and 'flow' is the norm. Right now, more than half of work hours are spent on coordination and communication—less on creating. With Velt, we're setting out to reverse these figures, reducing time spent on logistical issues by over 90%. Imagine what we can create when we spend less time talking about work and more time doing it! We're building a better web—a web for us, for our team, for everyone. Join us, and let's accelerate the future of web together 🚀 Our Products: - Velt Collaboration SDK (https://velt.dev/): JS SDK to add powerful collaboration experiences to your own product for your end-users. This helps you ship such experiences ridiculously fast, increase user growth and engagement. - Superflow (https://usesuperflow.com/): JS plugin to enable product, marketing and design teams to comment and collaborate directly on their websites. This helps them iterate and ship their products 10x faster. We’re a team of ex-Googlers. We've launched products like Augmented Reality in Google Search & Maps. Come build a better web with us 🚀