API-First

$500K YC 2025; Pennie Huang/Pasha Rayan (ex-Forage acquired) founders; Twilio for AI; Communication APIs; YC W25

$500K YC W25; TechCrunch top 10; Jesse (ex-Waymo)/Ke (ex-YouTube/Brex)/Meji (ex-AWS) founders; Teleoperation API; YC W25

ActiveCampaign is a customer experience automation platform that combines email marketing, marketing automation, sales automation, and CRM capabilities in one solution. The platform serves small to mi

Activepieces is an open-source workflow automation platform that serves as an alternative to Zapier, Make.com, and Workato, enabling teams to build automated workflows without code. Founded in 2022, t

Airbyte is an open-source data integration platform that enables organizations to replicate data from applications, databases, and APIs into data warehouses, lakes, and databases. The platform serves

Airwallex is a global payments and financial platform serving 150,000 businesses worldwide. $6.2B valuation, $1.2B raised. $1B+ annualized revenue (Oct 2025, +90% YoY), $130B+ annualized payment volum

Anchor is a Lagos-based embedded finance platform that provides banking-as-a-service APIs and tools enabling developers to integrate banking products including accounts, transfers, savings, cards, and

Anthropic is an AI safety and research company focused on building reliable, interpretable, and steerable AI systems, best known for developing Claude, a family of large language models. The company s

Apigee is Google Cloud's API management platform acquired by Google for $625M in 2016. Named Leader in 2025 Gartner API Management Magic Quadrant (10th consecutive year, highest for Ability to Execute

Archbee is a YC W21-backed documentation platform that provides AI-powered tools for technical teams to create, manage, and share documentation, featuring GPT-4 Write Assist, AI question answering, an

AssemblyAI is a Speech AI platform providing speech-to-text APIs and audio intelligence for over 200,000 developers worldwide. The company focuses on conversation intelligence and voice agent applicat

Authologic is a unified digital identity verification platform that streamlines KYC and AML processes for regulated industries by providing instant verification through government-issued digital IDs a

YC/Gradient Ventures (Google AI fund) backed; Plaid for insurance; Instant verification API; Auto lender/property focus; YC

Balance is a B2B checkout and payments platform enabling merchants to accept payments, offer net terms, and automate accounts receivable, boosting revenue by 30% in conversions, increasing buyer spend

BrowserStack is a cloud-based suite of software testing solutions that enables developers to test websites and applications across browsers, serving over 50,000 customers including tech giants like Go

Bruno is an open-source API client and IDE for exploring and testing APIs, positioned as lightweight alternative to Postman/Insomnia. Git-friendly, fast, offline-first design. Golden Edition provides

CaptivateIQ is a no-code incentive compensation management platform helping businesses automate sales commissions, bonuses, and variable pay calculations. The company enables finance and revenue opera

Checkout.com is a global payments platform processing $300B+ annually. $12B valuation (down from $40B peak in 2022), $1.83B raised. 45% YoY revenue growth in 2024, achieved profitability. 40+ merchant

Checkr is an AI-powered background check platform serving 100,000+ customers including OpenAI, Kia, and Subway. The company pioneered the first background check API and exceeded $700M revenue in 2024.

Clerk is the authentication and user management platform for developers, partnered with Stripe for billing integration. Serves 1,300+ paying customers managing 16M+ users.

Cohere is an enterprise AI platform that provides large language models and natural language processing capabilities for businesses to build search, content generation, and classification applications

Customer.io is a customer engagement platform that enables businesses to send targeted, behavior-driven messages across email, SMS, push notifications, and in-app channels to improve conversion and re

Daily is a developer-first WebRTC API platform providing best-in-market video call quality with secure, compliant global infrastructure. The platform offers real-time voice, video, and AI capabilities

Datafold automates critical data engineering workflows including data migrations, code testing and review, and monitoring and observability for modern data teams. Founded in 2020 by Gleb Mezhanskiy an

Decentro is a Gurugram-based fintech infrastructure platform that provides APIs and SDKs for banking integrations and digital payments, processing over ₹50,000 crore ($6B) in annual payment volumes. F

Deepgram is the voice AI platform for speech-to-text and text-to-speech APIs, serving 200K+ developers and 400+ enterprises. Ended 2024 cash-flow positive with 3.3x usage growth, over 1 trillion words

Dots is a San Francisco-based fintech company that provides developer-friendly payouts infrastructure through a multichannel API, automating payment processing, seller onboarding, and KYC workflows fo

Drata is a security and compliance automation platform that continuously monitors and collects evidence for SOC 2, ISO 27001, GDPR, HIPAA, and other compliance frameworks, streamlining audit processes

Duplo is a Nigerian fintech company founded in 2021 that provides businesses with an integrated platform to automate payables, receivables, and expense management, positioning itself as "Venmo for B2B

Exa is a San Francisco-based AI search engine that builds web search infrastructure specifically designed for LLMs and AI agents rather than humans, using embedding models and neural search technology

FarmLogs is a farm management software platform that helps farmers track field activities, monitor crop performance, manage records, and analyze profitability through mobile and web applications. The

Feedonomics is a product feed management and optimization platform that helps e-commerce brands and retailers syndicate product data to marketplaces, comparison shopping engines, and advertising chann

Fern is a New York New York-based API tooling company founded in 2022 by Danny Sheridan and Deep Singhvi building SDK and API documentation generator raising $13M total funding including $9M Series A

Finch is a San Francisco-based universal API for payroll and HR founded in 2020 by Ansel Parikh and Jeremy Zhang, integrating with 220+ HRIS and payroll systems through one unified API to standardize

Finix is a payment processing infrastructure company enabling software platforms to become payment facilitators. Raised $208M total (including $75M Series C Oct 2024), quadrupled revenue in 2024. Cert

Fintoc is a Santiago, Chile-based open banking and account-to-account payments API company founded by Cristobal Griffero and Lukas Zorich that enables online businesses to accept instant payments dire

Flagsmith is fully bootstrapped, generating $1M+ ARR (July 2024) from clients like Citi Bank and United Health Group after raising only $229K from Polychrome. Open-source feature flagging tool enables

Flex is a United States-based fintech company founded in 2023 by Sam O'Keefe Miguel Toledo building HSA FSA payment acceptance platform raising $18M total over multiple rounds including $3.2M seed Sep

FlutterFlow is a Mountain View, California-based no-code/low-code platform founded in 2020 that enables developers and non-technical users to build native mobile and web applications using Google's Fl

Flutterwave is Africa's most valuable fintech company providing payment infrastructure across 35+ countries. Valued at $3B with $95.3M revenue in 2024 (up 47% from $64.8M in 2023), processing $34B+ in

Formance is a Paris-based financial infrastructure company that provides open-source ledger and payment orchestration tools for fintechs, vertical SaaS platforms, and financial institutions. Founded i

GitHub Actions is a CI/CD and workflow automation platform integrated into GitHub that enables developers to build, test, and deploy code directly from their repositories. The company serves software

GoCardless is the bank payment network for recurring and invoice payments. The platform processes £40B+ annually for 94,000+ organizations worldwide, specializing in direct debit and open banking paym

H2O.ai is an enterprise artificial intelligence platform that enables organizations to build, deploy, and operationalize machine learning models at scale. The company serves data scientists, AI engine

Heron Data is a financial services automation company founded in 2020 by Johannes Jaeckle, Dominic Kwok, and Jamie Parker, automating document-heavy workflows in business lending, equipment finance, a

Hightouch is a reverse ETL platform that enables companies to sync data from warehouses to business applications, activating customer data across marketing, sales, and support tools. The company serve

Hoppscotch is an open-source API development ecosystem with 500,000+ developers globally. Total funding: $3M Seed (Dec 2021) led by OSS Capital, with Automattic (WordPress.com parent). Founded 2019 by

Hugging Face is an AI platform and community that provides access to pre-trained machine learning models, datasets, and tools for natural language processing and other AI tasks. The company serves AI

Humaans is a London-based AI-powered HRIS for high-performing teams founded in 2020 by Giovanni Luperti and Karolis Narkevicius. The platform reduces ongoing administrative work by 65% and onboarding

YC F25; Agent memory infrastructure; Slack/Gmail/Notion integration; AI coworker API; YC Fall 2025

Increase provides enterprise-grade banking APIs that enable technology companies to programmatically manage money through direct connections to the Federal Reserve, Visa, and other financial networks.

Infinia is a Montevideo Uruguay-based account-to-account payment company founded in 2022 by Alejandro Rettig and Ianai Urwicz providing programmatic money movement solutions for Latin America raising

Insomnia is an API testing and development platform acquired by Kong on October 2, 2019. 1M+ users (Sept 2024), fastest-growing platform for building, testing, debugging APIs. Founded 2014 by Gregory

Jestor is a San Francisco-based no-code/low-code platform that enables companies to build custom internal tools, automate workflows, and manage databases without extensive coding knowledge. Founded in

Jitsu is a cloud-based open-source data integration platform built to process large amounts of event data at scale in real-time. Founded in 2019 by Peter Wysinski and Vladimir Klimontovich, the San Fr

Kombo is a Berlin-based unified API platform that enables software companies to integrate with 100+ HR, ATS, and payroll systems through a single API, eliminating the need for multiple integrations. F

Kong is an API gateway and service mesh platform that closed a $175M Series E in Nov 2024 at $2B valuation led by Tiger Global. Revenue $146.1M in 2024 (up from $100M in 2023). Total raised $345M from

Lendflow is a New York-based embedded lending infrastructure company founded in 2020 that enables software companies to integrate lending services into their products through API-based credit solution

Lightspeed is a cloud-based point-of-sale and commerce platform serving retail, restaurant, and hospitality businesses with integrated payment processing, inventory management, and customer engagement

Malga is a São Paulo-based payment orchestration platform that enables digital businesses to access 25+ payment providers through a single API integration, allowing transaction-level provider switchin

Marketo is a leading marketing automation platform, now part of Adobe, that provides email marketing, lead management, consumer marketing, and account-based marketing capabilities for B2B and B2C mark

Mistral AI is Europe's leading AI foundation model company. €60M revenue projected for 2025 (5x from €10M in 2023), €11.7B valuation in 2025, €2.8B total funding. €300M annual contract value secured w

Mito is a New York-based developer tools company that provides a JupyterLab spreadsheet extension that automatically generates Python code as users edit data, enabling Excel users to transition to aut

Modern Treasury provides payment operations software for automating money movement from initiation through reconciliation. First AI platform purpose-built for enterprise payments.

Mono is a Lagos, Nigeria-based fintech company that provides open banking APIs empowering businesses to connect with their customers' financial accounts across Africa. The YC W21 company raised $17.6M

MuleSoft is an Integration Platform as a Service (iPaaS) acquired by Salesforce for $6.5B in 2018. Part of Salesforce Integration and Analytics segment that generated $5.8B revenue (FY 2025, combined

n8n is the open-source workflow automation platform offering self-hosted and cloud options. Distinguished by AI-native capabilities with 70+ LangChain nodes, n8n competes with Zapier and Make.

Nango is a San Francisco California-based integration infrastructure company founded in 2022 building unified API platform for product integrations enabling developers to build maintain API connection

NanoNets provides AI-powered automatic data extraction from documents, enabling businesses to process invoices, receipts, and forms without manual data entry.

$20M Series A (a16z); Mahmoud Ghulman/Aziz Alghunaim (MIT 2x YC) founders; Walmart/7-Eleven clients; YC S21

NewsCatcher is a London-based web data company that provides a comprehensive news and web data API, processing 1.5 million articles daily from 140,000+ sources across 60+ languages. Founded in 2019, t

Nium is a cross-border payments infrastructure platform serving 190+ countries. $1.4B valuation (down from $2B in 2022), $551M raised. Revenue grew 50%+ in 2023. Network supports 100 currencies, real-

OpenAI is an artificial intelligence research and deployment company that develops advanced AI models including GPT-4, DALL-E, and ChatGPT for natural language processing, image generation, and reason

OpenAI Platform provides developer APIs and tools for integrating OpenAI's large language models including GPT-4, GPT-3.5, embeddings, and moderation capabilities into applications and services. The c

Palenca is a Mexico City-based fintech founded in 2021 that provides a payroll API enabling consumers to securely share employment and income data with financial institutions across Latin America. The

Paw is a Mac-native API development tool that was bootstrapped to $50K MRR before being acquired by RapidAPI in 2021. Founded in 2014 by a 22-year-old founder, Paw ran profitably for 11 years focusing

PayCaddy is a Panama City-based Banking as a Service platform that enables Latin American companies to launch financial products through API-based infrastructure, including digital wallets, payment au

Paystack is Nigeria's leading payment processor, acquired by Stripe for $200M in 2020. Processes 50%+ of Nigeria's online transactions, hit ₦1 trillion monthly volume in July 2024, serving businesses

Pier is a San Francisco California-based credit platform company founded in 2022 by Jessica Zhang building credit-as-a-service API raising $2.4M seed early 2024 from Liquid 2 Ventures Y Combinator ACM

Plaid is the fintech infrastructure company powering digital finance by connecting applications to users' bank accounts. Used by most top fintech apps for account linking and data access.

Planful is a cloud-based financial planning and analysis (FP&A) platform that provides budgeting, forecasting, reporting, and scenario modeling tools for finance teams. The company serves mid-market t

Postman is an API development platform providing tools for designing, testing, documenting, monitoring, and collaborating on APIs throughout the development lifecycle. The company serves developers, Q

Prequel is a San Francisco-based data integration and transformation platform founded in 2021 that enables SaaS companies to build embedded ETL pipelines and data integrations for their customers. The

Primer is a payment orchestration platform enabling merchants to build customized payment flows. $425M valuation, £28M cash (2023). Revenue grew to £2.9M in 2023, projected £6M in 2024 (+200% growth).

Productive.io is an all-in-one agency management platform designed for creative and professional services firms to manage projects, track time, allocate resources, and monitor profitability. The softw

Propexo is a Boston Massachusetts-based commercial real estate API platform company founded in 2022 by Nick Johnson, Ben Keller, Remen Okoruwa building unified API for multifamily property management

QuestDB is an open-source time-series database offering blazingly fast ingestion and dynamic, low-latency SQL queries through column-oriented storage, parallelized vector execution, SIMD instructions,

RapidAPI is an API marketplace platform with $44.9M revenue in October 2024, serving 55K customers and 4M+ developers. Acquired by Nokia on November 13, 2024 after reaching $1B valuation in March 2022

Rapyd is a global fintech-as-a-service platform offering payments, payouts, and embedded finance via API. $3.5-4.5B valuation (down from $15B peak in 2022), $2.01B raised. Operates in 41 regulated cou

Razorpay is India's leading payment gateway with 55%+ market share, processing $210B in total payment volume in 2025. The platform serves 12M+ merchants with comprehensive payment and banking solution

Regie.ai is an AI-powered sales engagement platform that automates and personalizes outbound prospecting through generative AI technology. The platform creates customized email sequences, generates pe

Release provides Environments as a Service (EaaS) for development teams, offering ephemeral, test, QA, and staging environments that can be created on-demand to streamline development and remove bottl

Replicate is a cloud platform that makes it easy to run and deploy machine learning models at scale through a simple API. The service provides access to thousands of pre-trained models for image gener

Rollbar is a full-stack error monitoring platform for web and mobile applications providing real-time error tracking and debugging tools. Total funding: $17.4M-$25.9M (sources vary) over 4 rounds; lat

Routable simplifies B2B payouts at scale, enabling businesses to send payments via ACH, checks, and international transfers through a single platform with approval workflows.

Safepay is Pakistan's first Y Combinator graduate fintech, operating as a regulated Payment System Operator/Provider Service Provider (PSO/PSP) with a commercial license from the State Bank of Pakista

Scoro is a comprehensive work management platform designed for professional services firms and agencies to manage projects, track time, handle finances, and collaborate across teams. The software inte

Shippo provides a shipping API platform that enables e-commerce businesses to access discounted shipping rates from multiple carriers through a single integration. Powers shipping for over 100,000 bus

Sivo is a San Francisco-based debt-as-a-service platform founded in 2020 that provides API-based debt capital infrastructure for fintech and technology companies, enabling platforms to offer financing

Slash is a Los Altos, California-based fintech company that provides comprehensive financial services and corporate cards for high-spending businesses, including global payments, API, reporting, recon

Slope is an AI-powered B2B payments platform that provides flexible payment terms, automated invoicing, and credit management solutions for enterprise transactions. Founded in 2021 (YC W21), the compa

SnapTrade is a brokerage API integration platform that provides read and write access to retail brokerage accounts with near real-time data updates across 20+ major brokerages including Fidelity, Robi

Snyk is a developer security platform that helps organizations find and fix vulnerabilities in open source dependencies, container images, infrastructure as code, and application code. The company ser

Socotra is a cloud-native core insurance platform that enables insurers and MGAs to rapidly configure, deploy, and manage insurance products with modern technology infrastructure. The company serves p

Stacker is an online no-code platform enabling users to convert spreadsheet data into enterprise applications without programming knowledge. Founded in 2017 by Michael Skelly and Sam Davyson, headquar

Stark Bank is a Brazilian open banking API provider and digital business bank offering payment processing, banking infrastructure, and financial services for companies, with backing from Jeff Bezos' B

Stayntouch is a cloud-based hotel property management system designed for modern, mobile-first hospitality operations with flexible integrations and guest-centric features. The company serves independ

Strapi is the leading open-source headless CMS, 100% JavaScript/TypeScript, fully customizable and developer-first. Total funding: $49M (Series B June 2022: $31M led by CRV with Flex Capital, Index Ve

Superwall is a San Francisco-based mobile paywall platform that enables app developers to remotely configure and optimize subscription paywalls without app updates, processing 100 million monthly view

Swagger is an open-source framework and toolset for designing, building, documenting, and consuming RESTful APIs through the OpenAPI Specification. The company serves API developers, architects, and o

Swift is a United States-based embedded finance platform company founded 2023 by Rakeeb Hossain David Lalor raising $2.34M total over 2 rounds from 27 investors building embedded finance platform onli

Swoogo is an enterprise event management platform enabling organizations to create, manage, and measure virtual, hybrid, and in-person events with registration, engagement, and analytics tools. The co

Telnyx is a communications platform as a service (CPaaS) provider offering voice, messaging, wireless, and connectivity APIs for developers and businesses building communication applications. The comp

Thoropass is a compliance automation platform that helps companies achieve and maintain security and privacy certifications including SOC 2, ISO 27001, HIPAA, and GDPR through continuous monitoring. T

ToDesktop is a platform that helps developers convert web applications into desktop apps using Electron technology, providing infrastructure and tooling to simplify desktop app creation and maintenanc

TrueLayer is Europe's leading open banking platform for pay-by-bank payments. $700-750M valuation (down from $1B peak), $322M raised, processes $50B+ annually. 13M users, 40% UK open banking share, 80

Union54 is a Lusaka-based fintech company that operates ChitChat, an integrated messaging and payments platform combining secure instant messaging with USD digital wallets and Mastercard debit cards f

Unit is an embedded banking-as-a-service platform enabling companies to offer financial products. $1.2B valuation, $173M raised, $1.3B in deposits (+65% YoY). Serves 800,000 individuals, 300,000 contr

Versori is a London-based agentic integration platform that enables businesses to build, deploy, and manage custom integrations and workflows through its no-code, AI-powered automation solution. Found

Wasp is a full-stack web development framework founded in 2020 by twin brothers Martin and Matija Šošić that provides a declarative domain-specific language for building web applications with React, N

Whalesync is a San Francisco-based infrastructure company that provides no-code bi-directional data synchronization between business tools including Airtable, Notion, HubSpot, Webflow, and PostgreSQL,

xPay is an international billing operations platform founded 2024 raising $500K Y Combinator February 27 2024 hitting $330K revenue 2025 projecting $5M annualized transaction volume launching four wee