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.

Click builds useful services that meet users right inside ChatGPT and Claude. We're starting with a research service that provides external context that the built-in web search misses - like data from professional & social platforms, marketplaces, financials, and more. It makes research on people & companies even deeper with specialized, source-backed context beyond built-in web search, while enabling new tasks like comparing live flight fares right inside the chat.

Luca IQ is an API for deterministic tax calculation and an IRS Authorized e-filing engine - the foundation for accounting firms and fintechs building on tax.

Archal provisions sandboxes with the API environments your CI, tests, and evals need. Your coding agent can start the sandbox & environments, connect to your API integrations, run tests, and inspect state changes. Sandboxes and environments are startable within seconds and take milliseconds to reset.

We build human foundation models. Our first family of models powers lifelike avatars that interact with users in real time, enabling AI agents and applications to go beyond text and voice with just a few lines of code. State-of-the-art realism with ultra-low latency at scale.

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.

Captain syncs complex, multimodal files and cloud storage from sources like S3, SharePoint, and Google Drive, and makes that knowledge searchable for your agents. Instead of stitching together parsers, embeddings, vector databases, rerankers, and retrieval infrastructure, Captain self-tunes the retrieval pipeline to your data and workloads. On benchmarks, this improves accuracy from roughly 78% with standard RAG to over 97% by tuning retrieval to the unique structure and content of your data. Captain is purpose-built for complex, regulated, and high-stakes file search workloads. Learn more at https://captain.dev

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.

Tesora builds frontier AI agents for actuaries at P&C carriers, reinsurers, and MGAs. The agents handle the assembly, pulling the data, running the method, and deploying the rater, while you review the work and make every call. We deploy inside the stack you already run, on your infra and under your IT team's control, with no shared servers and nothing to rip out. Your data never trains our models, or anyone else's. We treat this as a partnership so we stay hands-on until the work is live and holding up in production. That standard runs through our security posture too: SOC 2 Type II certified, with a full audit trail behind every change. The part of the job that matters is actuarial judgment, and we automate everything around it so you get back to the work only you can do. Built by AI technologists and actuaries who want to see this exist and backed by Y Combinator & other top investors.

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

We build autonomous research agents that accelerate frontier world models.

Parsewise provides multi-document processing and analysis that you can embed in your own product. Operations teams use our platform for oversight and control over their fleet of AI agents, and our MCP to make Claude work at scale with traceability. Tech teams use our API to replace complex processing pipelines resolving values across documents. We help customers assess complex risk at scale: manage casualty, specialty, KYC, and financial risks, so teams can act faster and defend their decisions with confidence.

superglue learns how your systems work from your company's knowledge and performs the implementation that normally requires human coordination and engineering work. Implement NetSuite, Sage Intacct, SAP, Business Central or Acumatica in days. Agents map and migrate legacy data, configure the system, and keep data in sync post go-live. Connect ERP, CRM, databases, and internal systems to AI platforms like Claude. Create governed data access for AI agents and track data usage across your org. Connect customer systems, import historical data and get new integrations live in hours. Let agents manage the entire implementation process end-to-end.

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 with 110k+ Github stars.

Hello! 👋 We are a team of former ML engineers, founders, roboticists and ops leads who obsess about data and its impact on safe, reliable AI. We specialize in creating environments and datasets for RL by leveraging our experience in simulation and model training. By the numbers: • Powering 3 of the top 6 global AI labs and multiple Fortune 500 enterprises • Billions of training tokens generated each month, 2x month over month • Exclusive, global network of over 500 domain experts We believe humans are inherently creative, and thrive by pushing the frontier. We are working towards an abundant future--one where everyone has access to infinite intelligence, services and goods. Based in San Francisco, CA. We enjoy good food and good company. -- more info below -- Abundant is building the NVIDIA of training data. AI models rely on two fundamental ingredients: compute and data. NVIDIA, the leader in compute, has a peak market cap of $5T and generated $130B in revenue last year as the need for scaling compute has exploded. We believe the need to scale data is just beginning, as we move beyond SFT and human supervision to RL and Learning from Experience. Our founding team consists of second-time founders, ML engineers and data leads from Waymo, Google, Meta and AWS. Our team has previously collaborated with DeepMind to classify hate speech in YouTube videos, trained SOTA models for self-driving, and scaled data pipelines with thousands of human annotators. Our pioneering work in human computation, synthetic data, imitation learning and RL give us a solid advantage in delivering results to our customers. Why now? Training data is more important and more scarce than ever before. Scaling laws dictate that linear improvement in model performance demands an exponential increase in training data. But there is only one World Wide Web and most of it has already been trained on. The next advances will require new, diverse, and high-quality datasets, making training data more important and scarce than ever before. What happens if we succeed? Abundant will be the core enabler for AGI and beyond. Most of the challenges in model training are already solved. What’s missing is the data necessary to move from general knowledge to domain expertise; from chatbots to agents; and from digital intelligence to physical AI. Ask any AI researcher or roboticist: the core bottleneck to progress is the availability of data, i.e. “abundant data”. Abundant works with the most advanced AI labs and startups, as well as F500 enterprises.

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.

The best DOCX MCP for agents. read and edit docx without having you agents deal with XML. Save on cost, enjoy improved performance. Perfect for regulatory, compliance and legal agent builders dealing with documentation

VideoGen makes it easy for anyone to create professional, copyright-free videos in seconds. Our AI video generator turns a prompt, script, or article into a finished video, complete with AI voiceover, subtitles, and b-roll, powered by the latest models like Sora, Veo, and Kling. Today, over 5 million users trust VideoGen, from individuals and small businesses to teams at Google and ByteDance. Making videos is hard, time-consuming, and expensive if you hire someone to do it for you. With VideoGen, it only takes a few clicks! Try it at https://videogen.io/, or build video into your own product with our API: https://videogen.io/videogen-api

Scape is the intelligent email inbox, built for the one billion professionals who spend most of their workday in email. Designed to work proactively, Scape surfaces only the emails that need attention and prepares drafted responses, ready to review and send.

The physical economy still operates without a common language. Enterprise systems, factories, trucks, and robots generate enormous amounts of data, but most remains fragmented across legacy software and incompatible formats. Without a shared understanding of what is happening, even the most advanced AI cannot reliably coordinate how goods are made, moved, and delivered. Oway is building that common language. Our protocol, IOI, connects enterprise systems and physical hardware, cleaning messy legacy data and live telemetry into a standardized schema that AI can understand and act on. Through a shared API, businesses can query their operations, identify inefficiencies, and automate actions across systems without replacing their existing software. Our first model, Juno, applies this intelligence to unused truck capacity. It tracks empty space on trucks and sells it at a 50% discount to businesses shipping in the same direction. By moving freight directly on trucks already making the trip, Oway reduces shipping costs, damage, and transit times while generating additional revenue for carriers. Every connected system and shipment expands our understanding of capacity, pricing, routes, facilities, and industrial operations. As this network grows, Oway is building toward a future where enterprise software, automated factories, self-driving vehicles, and robots can communicate and coordinate through one shared layer, making the physical economy programmable.

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

Integuru turns any platform into a reliable, low-latency, and high-throughput API. Requests complete in 3 seconds with 99.9%+ success, including deployments above 1M requests/month/platform. No RPA or browsers. No data caching needed. (By Taiki, Inc.)

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.

Magic Hour is a browser-based creative platform and API for generating and editing video, images, and audio. Creators and teams use more than 100 tools, including face swap, lip sync, image-to-video, text-to-video, image editing, and voice generation. Developers integrate the same capabilities through our REST API, official SDKs, and hosted MCP server.

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.

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.

Opensteer creates specialized AI agents in cloud computers that can integrate with anything. Each agent gets customizable browser access, tools, instructions, and guardrails, so it can work 24/7 exactly the way you need.

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 builds telematics data infrastructure for the commercial fleet industry. Commercial auto insurers and fleet software companies, including industry leaders like Intact Insurance, depend on our platform to access GPS, speeding, and vehicle data from 330+ telematics providers. We recently raised our Series A led by Battery Ventures and are backed by Y Combinator, Golden Ventures, Penske Transportation Solutions, and Intact Private Capital. Our team works together in person in Toronto, combining early-stage speed with late-stage maturity while processing many terabytes of vehicle data every day.

Specialized inference, built for agent workloads Fast Open-Source models: Kimi k3, Deepseek v4 flash, qwen 397b, at 200+ tps Specialized models for applying edits, code search, compaction, and model routing

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.