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

Checkr builds people infrastructure for the future of work. And we believe everyone should have a fair chance to work. That's why we've designed a faster—and fairer—way to screen job seekers. For more information on our mission and products, visit http://checkr.com.

Mux is an API-first video platform designed by experts to make world-class video streaming and analytics possible for every development team. Self-optimizing videos take the guesswork out of encodings, delivery, and renditions. Mux makes your video look beautiful on every device, every time. We offer two products, Mux Video and Mux Data. Mux Video is a simple API to advanced video streaming. Powered by data and designed by video experts, Mux Video makes beautiful video possible for every development team. Post a video or live stream with a single API call, and watch it within seconds. Mux Video handles the encoding, storage, and delivery. QoE and performance analytics provided by Mux Data is included by default for every Mux video stream.This real-time data is used to create the right renditions for every device and title, resulting in greater reliability and better viewer experiences. Mux Data is a Quality of Experience analytics platform that measures the performance metrics that actually matter to viewers: rebuffering, startup time, video quality, and errors. Our intuitive dashboard quickly gives users the insight to find issues and make improvements through features like A/B testing, industry-wide scores, alerts, and detailed information about every single video view. The product works out of the box on HTML5, iOS, Android, and major OTT platforms. All data is available via exports and APIs, making it easy to integrate Mux Data into other systems.

Deepgram is a foundational AI company on a mission to understand human language. We give any developer access to the most advanced speech AI transcription and understanding with just an API call. Our models deliver the fastest, most accurate transcription alongside contextual features like summarization, sentiment analysis, and topic detection. Beyond that, developers can: 🔊 Process live-streaming or pre-recorded audio 🌎 Transcribe in dozens of languages ⚙️ Train custom models for unique use cases 🔑 Access deep NLU with a unified API 💻 Build in any programming language with our SDKs ✅ Deploy on-prem or on DG’s managed cloud 📈 Get scalable GPU infra for training and inference Deepgram is a proud NVIDIA partner and Y Combinator company, and we recently completed a $72M Series B to define the future of AI Speech Understanding, making us the most-funded speech AI company at its stage.

Modern Treasury offers tools that automate the full cycle of money movement—from payment initiation, through approvals, to reconciliation—and are accessible through web application or API.

Alpaca is an API infrastructure and licensed financial services company that allows developers and businesses to offer stock and crypto investing to their end-customers. We work with more than 100 companies across the globe to enable their investing products, and our mission is to provide financial services to everyone on the planet. Alpaca’s globally distributed team consists of developers, traders, and brokerage business specialists and backed by a group of well-capitalized investors including Portage Ventures, Spark Capital, Tribe Capital, Unbound, Social Leverage, Horizons Ventures, Y Combinator as well as highly experienced industry angel investors and founders. We are also very tech-enthusiastic with notable track records in open-source and startup communities.

React Library, API, and Management Toolkit, purpose built for customer-facing dashboards.

Seam lets developers connect and control 3rd-party connected devices like door locks, thermostats, and more.

Dots is a developer-friendly API that lets businesses pay their contractors through just a few lines of code. Whether its gig workers like Uber drivers, sellers on marketplaces like Etsy, or simply your local handyman - Dots’ abstracts away the complexity of payouts completely. We manage the entire process: information collection (KYC), payments through any rail (ACH, Venmo, CashApp, Zelle, international, and many more to come), and even filing tax forms! Dots lets developers get payouts up and running over just a few hours, rather than the many months this would normally take.

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 🚀

Next-Gen API Documentation with AI Brilliance. Generate Stripe-like API docs in just a few seconds.

A personal cloud storage platform that's so good, it'll replace Finder / File Explorer on your desktop. Find anything with multi-modal, natural language search. Browse with a lightning fast interface that feels just like native. Organize, tag, view, edit, share, and more.