API Startups funded by Y Combinator (YC) 2026

The world’s largest omnichannel communications platform. Bird CRM powers communication between businesses and their customers — across any channel, always with the right context, and on every corner of the planet. Its products and solutions are the foundational building blocks to business communications across preferred channels, like SMS, Voice, WhatsApp, WeChat, Messenger, Email and more. Founded in 2011, Bird connects to billions of devices and is trusted by nearly 20,000 customers worldwide. Headquartered in Amsterdam, Bird operates across nine global hubs — including Singapore, Dublin, Shanghai, Sydney, London, Bogota and Asuncion — and is proud to be a “Work Anywhere” company. Its team of 500 employees represent more than 55 nationalities.

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.

Our interactive video models turn agents into lifelike video calls. Deploy in minutes with a few lines of embed code. Photorealism, emotion, and scale for just $0.06 per minute.

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.

Captain delivers the most accurate file search engine built for AI agents. We’ll index data from the sources folks already use like S3, SharePoint, and Google Drive, and easily scale multimodal, petabyte-level content search. We’re the Snowflake for Unstructured Data. Captain tops the Open-RAG-Benchmark with over 20% higher accuracy than standard RAG pipelines. We achieve this through robust data processing techniques like embedding normalization across modalities, ensuring that representations cluster by semantic content rather than data type.

Parse lets developers build APIs for any website. Unlike traditional scraping tools that rely on slow, expensive headless browsers, Parse examines websites' underlying network requests and generates API endpoints automatically. This makes Parse 10-100x faster and cheaper than browser automation,.

S2 is an API for durable streams. We make working with streaming data dead simple and reliable. 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.

Nozomio is a product and research lab solving context, starting with Nia. Nia is a search and index API. We continuously provide context from docs, research papers, datasets, codebases, and more so agents never rely on stale data. Scalable, 5x cheaper, and reliable.

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

Klavis AI is Open source MCP integration platform that let AI agents use tools reliably at any scale. Our API provides hosted, secure MCP servers, eliminating auth management and client-side code. Co-founder Xiangkai Zeng co-authored the Gemini paper and pioneered the tool calling infrastructure for Gemini. https://www.klavis.ai/

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.

ReJot is building Fragno to let API companies go from simply exposing an API to offering drop-in integrations that work out of the box. Fragno is an open‑source framework for packaging backend endpoints, data storage patterns, and frontend utilities into reusable building blocks. API providers ship full integrations, not just low‑level SDKs and docs. Customers configure rather than write code, so integrations are both much faster to launch and far more consistent across customers.

BlindPay is a stablecoin API that enables companies to send and receive money worldwide using fiat money, stablecoins and multiple blockchains. We handle all the complex compliance and regulatory requirements, so companies can focus on their core business.

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

We enable AI to control the browser. Browser-use is the biggest open-source web agent project. We got 40k stars in the last 3 months.

Surge is Stripe for telephony. Our team has experience building telephony software at billion dollar scale. Because of increased regulation, Twilio and other SMS APIs take weeks to onboard new customers, but we can get startups onboarded same day. Surge wins by enabling easy carrier registration, better support, and higher level APIs and no code UI components to make implementation easier for startups and developers.

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, low-latency, and high-volume API. No RPA involved. We specialize in delivering the most robust integrations, processing millions of API calls monthly at 99.99%+ success rate.

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

Precip uses AI to make hyperlocal weather observations. We’re started with the most important dimension of weather: rain. For example, one of our customers uses Precip daily to make sure their heavy trucks won’t get stuck in muddy fields. Our highly rated mobile app is the best way to see rain and snow totals anywhere.

Generate AI agents with plain English, edit visually, customize with code in your own IDE. Currently automating millions of tasks across support, sales, finance and more for companies like eToro, Payoneer and JustEat.

The first version of RecipeUI was a viral project at Robinhood that reached 100% adoption from all engineering and QA teams. When an API broke, anyone from Frontend to QA to PMs could debug without relying on backend engineers

Inconvo is the open-source platform for building data agents on production data. With safe queries, permissions, and structured outputs. Use Inconvo to build and deploy data agents that query production databases and can be called directly from your application. You get safe query execution, permissions, stateful conversations, and observability out of the box.

Glide lets apps accept crypto deposits from any chain, wallet, or exchange using pre-built wallet funding flows. Users can fund wallets directly — no bridges, no swaps, no repeated KYC.

Smobi is the AI-powered platform for branded, interactive business messaging, starting with RCS. We help businesses send rich, personalized messages that drive engagement, build trust, and create real conversations.

Oversteer is building browser agents to automate web tasks and turn them into reusable, deterministic APIs. You can integrate the API into any system and automate/integrate any website or portal.

Sohar Health is an AI-driven front-end RCM solution that transforms insurance verification processes for healthcare providers, enabling faster patient conversions and reducing administrative workloads. With a 95% automation rate, our API-first platform seamlessly integrates into existing workflows to provide real-time claim accuracy and eligibility checks. Key performance metrics showcase the power of our technology: Median latency of just 6 seconds, ensuring real-time eligibility; over 90% of checks returned within 30 seconds for increased patient conversion; 96% accuracy in identifying and verifying benefits details; Industry-leading 99% accuracy for eligibility determination; >90% carve-out detection rate, mitigating surprise billing risks; a 60% success rate with our Insurance Discovery API, helping identify coverage for self-pay patients. Our customers include outpatient clinics, specialty practices, and digital health platforms looking to streamline front-end claim management. By reducing errors and maximizing clean claim submissions, Sohar Health empowers healthcare organizations to convert and retain more patients, reduce operating costs, and increase their top-line revenue.

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

Terminal is Plaid for telematics data in commercial trucking. Companies building next generation insurance products, financial services and fleet software for trucking use our Universal API to access GPS data, speeding data and vehicle stats. Raghav (CEO) and Connor (CTO) led product and engineering at a series b-funded neobank where they spent 2.5 years integrating middleware APIs like Plaid & Stripe. Before that, Connor spent 3 years building software for his family-owned logistics company which was acquired by a private equity firm. Raghav’s family is in fleet operations and owns an HVAC company in San Francisco where they operate a fleet of 13 commercial vehicles.

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

Fastgen is a low-code API and workflow builder with an integrated Postgres DB. Our drag-and-drop platform allows you to rapidly develop custom APIs and workflows with ease. Our integrated Postgres DB makes it even easier to create, read, update, and delete data in your applications.

SuperAPI is a programmable API gateway that makes all your fetch APIs cacheable, reducing the response time 10x. Our customers use SuperAPI to cache their critical APIs without spending 6-9 months rewriting their code.

SpecCheck is an all-in-one solution that provides accurate prescription eyewear ordering and tracking, seamless billing, and streamlined communication between patients, eye doctors, and their lab partners. SpecCheck’s users work more efficiently and make fewer costly errors, increasing productivity and improving their overall workflow.

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.

Replace legacy scanners and manual offensive security processes with AI agents that discover, test, and remediate directly in your engineering workflows.

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.

Propexo lets engineers build, test, and launch CRE software integrations in days, not months. We modernize the developer experience for our customers, providing clear documentation and robust infrastructure to support the needs of property owners, property managers, & proptechs.

Anchor provides APIs, dashboard and tools that help developers easily embed and build banking products. This includes APIs for creating bank accounts, funds transfers, savings products, issuing cards and offering loans. We also provide regulatory coverage and continuous compliance support to our partners.

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

MovingLake is Fivetran for event-driven architectures. Companies such as Casai use our product to obtain orders and price changes in real time.

Assign Tasks by Call, E-mail, or Message — Your Assistant will Handle the Rest! https://unify.ai ✨

Intuned is an AI enabled cloud platform to author, deploy, and monitor integrations to extract web data and execute browser automation. We enable engineers to build reliable integrations to access data and complete actions on other web services when official APIs are not available or complete.

Sunlight is an API to change the card-on-file with apps and subscription services. Fintechs use Sunlight to automatically make their cards top-of-wallet as soon as they're issued. Merchants, service providers and subscriptions-based businesses everywhere now offer their customers the ability to save a debit/credit card on file, so they can pay their bills on time, buy in one click, or earn rewards. In 2021, 79% of consumers worldwide reported already having at least one payment card saved with a service or being open to doing so. In recent years, card-issuing as-a-service has become mainstream: any company can now start their own card business in a matter of weeks. Last year, the number of new payment cards issued was at an all-time high. For users, however, switching banks or opening a new card now comes with an additional hurdle: they need to update their payment info across the internet. On the other side of that equation, card issuers have no visibility or control over the card-on-file updating process, and as a result struggle to get their new users to switch their spend from their old card to the new one, leading to low conversion rates and missed revenue opportunities. Until Sunlight. With our universal get-your-card-on-file API, FIs can now offer their users, at any point in their journey, a quick and easy way to update their debit/credit card info everywhere they shop or pay online, without ever leaving their Apps. The Sunlight API works on every platform that has a card-on-file option (think Uber, Amazon, Netflix, DoorDash, Starbucks and so many more…), is as seamless as a Plaid connection, and always gets the card number and CVV code right on the first try!

Typewise is an AI-first customer service platform where orchestrated agents resolve requests end-to-end by taking real actions across your stack. Teams describe outcomes in natural language and the platform compiles them into working automations—no flowcharts, no code. You can safely simulate changes and roll them out step by step. Fortune 500 brands such as Unilever and DPD use Typewise to cut support effort by 50%+ while increasing CSAT and NPS. With 200+ integrations, Typewise reads from and writes to CRM, ERP, and other systems to fully resolve cases, handing off to humans only where they add the most value. Hybrid intelligence enables partial hand-offs, review-before-send, and context-preserving resumption—so teams stay in control. Operate natively within Typewise Ticketing, with optional integrations into your existing CRM or helpdesk systems such as Zendesk, Salesforce, or Freshdesk, and enhance agents with a CRM-embedded copilot. A company-specific AI language model keeps every interaction on-brand. EU-hosted and ISO 27001 certified, Typewise delivers measurable ROI in weeks—so you can start small and scale automation with confidence.

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.