API Startups funded by Y Combinator (YC) in the San Francisco Bay Area 2026

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 https://checkr.com.

Your agent processed a refund without looking up the order ID, costing you thousands. You only found out three hours later from a support ticket. Evals, output scoring, and observability can reduce the likelihood of mistakes like these occurring - but there's no solution that inspects and prevents an action as it’s about to execute. Salus does that. We’ve built an API that wraps around your agent and checks its actions at run time, blocking incorrect ones and providing immediate feedback to guide retries. Kevin and Vedant were roommates at Stanford, where they both studied computer science.

APIs weren’t built for agents. Orthogonal fixes that. Developers and agents get instant access to hundreds of APIs through our MCP or SDK. No API key management, no billing headaches, pay as you go. API providers list once and become instantly discoverable.

Shofo builds large-scale social media training datasets by collecting, labeling, and enriching public content for pre-training and fine-tuning AI models. Our indexes continuously collect and update every video across hard to access social media platforms. Companies use Shofo to avoid building their own data collection and processing systems and spending months turning unstructured social content into model-ready data. We started with TikTok and are expanding across every major social platform.

It's never been easier to turn ideas into apps, it should be just as easy to take those apps to production. SideKit provides one SDK to manage app versions, set feature flags and install privacy-first analytics to track usage. Update broke your paywall? One click to block the version. Made a breaking change and don't want users on your old version? One click to set a minimum version. Version gating is also completely free regardless of how many users you have.

Agentic Fabriq is the single control plane for data permissioning throughout your entire organization across your AI and employees. Through Fabriq, any employee can tap into AI/agents with exactly the data and tools they're cleared to use by an admin. Fabriq can be used internally with employees or externally for customers while handling the auth + integrations + permissions securely for you.

S2 is a serverless datastore for real-time, streaming data. The more we worked on data systems, the more we felt like there was a missing building block. The seamless experience of object storage simply did not exist for durable streams – so we set out to fix that! S2 reimagines streams as an unlimited and access-controlled web resource. Like if Kafka and S3 had a baby. - Building agents? Use granular streams to persist context in real time, make workflows auditable, and coordinate between agents. - Publishing fast-moving data? Streams support high fanout and can be accessed directly over the internet, so they are a great fit for broadcasting real-time feeds. - Sandboxing? Emit to per-instance streams, and read history or live events just as easily. - Local-first and multiplayer experiences? Propagate updates reliably and efficiently. Stop dealing with clusters, and start streaming.

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

superglue replaces brittle SQL scripts, cron jobs, and one-off connectors that power enterprise operations with clean, versioned syncs you can actually understand and trust. It rebuilds the logic behind integrations, so migrating systems, adding tools, or scaling processes no longer breaks everything. Companies running on superglue roll out AI projects faster, spend less on maintenance, and future-proof their business for continuous optimization.

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

Ultralight is a GPU-accelerated toolkit to embed modern HTML in games and native apps. Available for C and C++ on Windows, macOS, Linux, Xbox, PlayStation, ARM64 devices, and more. Developed in collaboration with leading game studios, built GPU-first on a new, lightweight fork of WebKit.

Automatically organizes your team's emails and meeting notes. Find anything in seconds, get intelligent email drafts, and reclaim hours every day.

Panora automates PO entry for distributors, manufacturers and wholesalers. Stop wrong shipments, block duplicates, reclaim ~80% of your order-entry time.

Integuru turns any website into a reliable, real-time, and low-latency API. No RPA required. Our services include authentication management and integration maintenance.

Downlink is a platform that continuously improves your AI. Boost rate limits, slash latency, and raise accuracy.All through one simple API.

Tesseral is the open source platform for managing identity and access in business software. It provides enterprise-grade capabilities, including SAML single sign-on, SCIM provisioning, role-based access control, managed API keys, and audit logs, implemented in just a few lines of code. Tesseral unifies access management for employees, customers, services, and AI agents, giving organizations the flexibility to adapt to any deployment model and the authority to enforce security policies with precision. You can learn more by reading our docs at https://tesseral.com/docs or by checking out our GitHub at https://github.com/tesseral-labs/tesseral.

Skyvern helps companies automate browser based workflows using LLMs and Computer Vision, fully automating manual workflows and replacing brittle or unreliable scripts. Examples include: 1. Automating materials procurement from commerce websites 2. Completing complex multi-step workflows (ie getting an insurance quote from Geico.com) 3. Automatically logging into portals and downloading invoices 4. Navigating legacy content systems to do data extraction or data entry

Fast Apply - Edit Files Faster - 10,500 tok/sec WarpGrep - Fast Context - 5x faster agentic code search subagent. eliminates context rot Glance- Videos of AI testing your PR, embedded in GitHub

Mercoa helps AP and Spend management platforms drive more virtual card volume from their BillPay customers. Our agent identifies card-eligible invoices and securely pays them through supplier portals or payment links.

PoplarML lets you deploy any machine learning model to a fleet of GPUs as a ready-to-use and scalable API endpoint with one command.

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.

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.

Typeless is an AI messaging API designed to facilitate communication for businesses and professionals. Our API generates smart, context-aware response suggestions to enhance messaging platforms in a variety of industries, from real estate to customer support. For example, a real estate platform can use Typeless to automate responses for scheduling property viewings, answering client inquiries, and handling follow-ups. Similarly, a customer service platform can enable agents to respond faster with personalized, AI-driven suggestions for customer questions and issues. You can download our demo messaging app built with the TypeLess API on the app store: https://apps.apple.com/us/app/typeless-ai-messenger/id6478489620

Metriport provides real-time access to comprehensive medical data for 300M+ individuals across the US. Our open-source intelligence platform helps organizations access, analyze, and exchange patient data while integrating with all major healthcare IT systems. If you’ve been to doctors in the US, you may have encountered the problem: how does a healthcare provider get access to your up-to-date medical history to treat you properly? Reliance on archaic methods is still the norm: typically, you or your provider need to call the facilities where you’ve previously received treatment (assuming you remember them all), just to have them send your records via fax (yep, fax). This can take weeks, only then to have a provider sift through hundreds of pages of unstructured docs, just to figure out basic things like your active medication list, what conditions you may have, latest lab results, etc. This not only delays care—it can cause improper treatment, since the medical history is critical for informing treatment decisions. Metriport integrates fragmented medical data from thousands of sources—including both national and state/regional Health Information Exchanges (HIEs), ADTs, EHRs, pharmacies, and labs—through a single API connector. The platform then standardizes, deduplicates, and enriches this data to create a comprehensive longitudinal patient record, with AI-powered clinical summaries. Along with a rich understanding of patient health history, healthcare providers also get realtime updates about their patients' health through Metriport. This includes getting notified when a patient is discharged from the hospital, picks up their prescription from the pharmacy, or has a new lab result available. Through this data, care teams get insights across their patient population, helping with 30-day readmissions prediction, care gap closure, risk adjustment, and more. On top of all of this, Metriport enables healthcare organizations to share net-new clinical information back to all major healthcare IT systems, and to become interoperable with popular EHR systems such as Epic, Cerner, athena, eClinicalWorks, and many more—forming an internet for healthcare data. Metriport improves both patient and provider lives at the point-of-care, supporting use cases such as medication adherence, transitions of care management, chart prep, and much more. If you want to do work that matters, get in touch with us today.

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.

Instead of just links, Andi AI gives you answers - like chatting with a smart friend. Andi is a new type of search engine that uses generative AI and language models combined with live data to generate factually correct answers to questions, and to explain and summarize information combined from the best sources. Andi works as a search chatbot that's ad-free and privacy-focused. Ask Andi to... ✅ Answer questions 🧠 Find, summarize and explain information 🔍 Navigate and search the web Search is broken because of SEO spam, ads, and surveillance capitalism. Andi cuts through the clutter to get you straight to the knowledge you need. It presents results visually in a way that's easy to understand with a simple chat interface, and protects you from ad tech and distraction.

Emobi is a unified legal, financial, and technical infrastructure that delivers seamless, secure, and reliable EV charging across networks—powering apps, fleets, and automakers while maximizing charger utilization. Our secure, fully automated charging technology, JustPlug, works instantly with no special hardware, software, or setup, making EV charging effortless. With 122,000+ EV chargers integrated across the U.S. and Canada, Emobi is recognized as the largest EV charging ecosystem in North America. Backed by two provisional patents and 15+ enterprise customers, Emobi's technology is also trusted by the Department of Energy (DoE) and the Department of Transportation (DoT). To learn more, visit www.emobi.ai.

FlowEQ is the trusted provider of workflow automation for teams that need to accelerate their work, especially complex processes and high-volume workflows that require human judgment. The FlowEQ Workflow Acceleration Platform includes interactive decision trees that are used by customer support, operations and product teams across all industries to improve accuracy and speed up important recurring work. Using FlowEQ customers get through high-stake recurring workflows 10x faster, saving their companies time and money every day. For additional information, visit www.floweq.com.

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.

Recall.ai is the API to get recordings, transcripts, and metadata from meetings. We offer several form factors to capture this data: 1. Meetings bots 2. A desktop recording SDK 3. A mobile recording SDK We integrate with meeting platforms like Zoom, Google Meet, Microsoft Teams, and more, as well as in-person meetings. Over 1000 companies rely on our API today to process millions of hours of meeting data. We provide stable infrastructure that typically takes engineering teams 6+ months of time to build, and help our customers get up and running in days instead of months.

At Gigs, we're building the operating system for mobile services - a platform that enables tech companies to seamlessly embed connectivity into their products. Just as Stripe enables businesses to embed a payment button into any product, Gigs enables businesses to add a connect button and issue SIMs with a single click or API call. From fintechs launching mobile services to HRIS platforms offering work phone plans, we automate phone plan provisioning. We're solving complex technical, operational and regulatory challenges to make connectivity truly effortless. We've grown to a team of around 90 people across the US and Europe, bringing together an experienced team of early-stage engineers, product builders and business athletes from companies like Stripe, Airbnb and Shopify. We know what it takes to solve hard problems. With almost $100MM in funding from Ribbit Capital, Google and Y Combinator, Gigs is one of the fastest growing tech companies. Building on our strong foundation, we’re looking for exceptional candidates who want to do the best work of their lives in a high-paced environment, surrounded by a highly talented, ambitious team. You’ll be joining at an exciting inflection point in our company’s history. At sub-100 people and with a year of hyper-growth ahead of us, opportunity is abundant.

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

Finch is the API to access payroll and HR systems. We allow admins to connect their company in a compliant and secure manner to applications. Finch integrates across providers enabling developers to access a previously closed system and are at the source of truth for employee data and money flow. Our API powers use cases across lending, insurance, benefits, FP&A, and HR applications.

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

Cosmic is a headless CMS and API toolkit to help teams build modern apps faster, together. We provide a web dashboard to create content and API tools to deliver content into any website or app. Teams benefit from using Cosmic because it eliminates the need to build and maintain their own CMS infrastructure. Teams pay a monthly subscription fee for our hosted CMS and can focus on their application logic, creating great content, and enhancing user experiences.

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.

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.

Founded in 2017, Treasury Prime is an embedded banking software platform connecting enterprise companies to a vast marketplace of banks and product partners to launch next-gen payment ecosystems on their platform. Our banking API offers the quickest, most secure way for fintechs and banks to partner, integrate and build modern financial products and increase revenue streams. We power enterprise-class embedded banking solutions for a range of complex services including money transfer, risk mitigation and integration with bank infrastructure. It's these leading-edge capabilities that helped the company to win Best Banking-as-a-Service Platform from Tearsheet in 2021 and 2022. The company was also named to CB Insights’ annual 2021 Fintech 250 list.

Today’s top Voice AI companies rely on AssemblyAI’s speech-to-text and speech understanding models to launch groundbreaking products fast and to scale with ease.

Veryfi's cutting-edge multimodal AI transforms documents into structured data with unparalleled accuracy, bulletproof privacy, and lightning-fast speed. Experience the power of data extraction, fraud detection & product intelligence. Veryfi gives you a fully integrated suite of data transformation products for you to securely capture, extract and transform bills, receipts and any other documents into structured data for use in your app, website or backoffice. To learn more https://www.veryfi.com/

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.

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.

Infrastructure for search teams building retrieval and RAG. Trieve combines search language models with tools for tuning ranking and relevance. Building excellent search is difficult and can take months to implement then even more time to maintain. Trieve offers production-ready infrastructure that works out of the box to help search teams build adjustable AI search and RAG into their products. With tools for custom models, relevancy weighting, date-recency biasing, semantic full-text hybrid search, recommendations, and more Trieve covers the full spectrum of what a team wants from their discovery infrastructure.

Play is a Voice AI company that specializes in building conversational voice models capable of cloning any voice or accent and generating speech in real-time.

EzDubs is a real-time speech translator. Our proprietary models translate speech without waiting for complete sentences, clone voices on the fly (without enrollments), and even replicate emotions in the translated language. Our iOS and Android apps translate live phone calls, automatically dub voice messages, and auto-translate text conversations so that you can communicate seamlessly across languages, with your voice and emotions. Thousands of users use EzDubs to communicate with friends and family who speak different languages, manage offshore teams, and even have relationships across languages. Visit https://ezdubs.ai to download our app and try a live demo of our real-time speech translator, or reach out to explore how EzDubs can integrate with your communication stack to enable live multilingual conversations.

Requestly helps developers build faster by intercepting, mocking, and testing API responses. No more waiting for backend developers, struggling with flaky staging environments, or fighting over API contracts. With 200,000+ active installs, Requestly is trusted by Google, Amazon, Workday, Indeed, and many other Fortune 500 companies.

Connect Twitter, GitHub, Stripe, Salesforce, and more through the power of GraphQL. Acquired by Netlify in Q4 2021.