API-First

A1Base is an AI agent infrastructure company that provides the identity and communication primitives needed to deploy AI agents in the real world. Building a functional AI agent requires more than a l

Abundant is an AI agent development platform that provides the orchestration infrastructure needed to build agents capable of completing complex, multi-step tasks autonomously over extended time horiz

ActiveCampaign is a customer experience automation platform providing email marketing, marketing automation, CRM, and messaging for small and mid-sized businesses — combining sophisticated automation

Activepieces is a San Francisco-based open-source workflow automation platform — backed by Y Combinator with $1.55 million raised from ByTheTower, Forward VC, Fundamental VC, Kima Ventures, and Soma C

Airbyte is a San Francisco-based open-source data integration platform enabling data engineers and analytics teams to replicate data from 350+ source applications, databases, and APIs into data wareho

Airwallex is a global financial technology platform providing multi-currency business accounts, cross-border payments, corporate cards, and embedded finance APIs for businesses operating international

Anchor is a Lagos-based embedded finance platform — backed by Y Combinator with $3.4 million raised including a $2.4 million seed round led by Goat Capital — providing Nigerian fintech developers and

Anthropic is a San Francisco-based AI safety and research company developing the Claude family of large language models — Claude 3.5 Sonnet, Claude 3.5 Haiku, and Claude 3 Opus — as well as the API an

Apigee is Google Cloud's API management platform providing the tools that enterprise organizations use to design, secure, publish, analyze, and monetize their APIs — serving as the management layer be

Archbee is a Bucharest-based AI-powered documentation platform — backed by Y Combinator (W21) with $4.04 million raised including a $3 million seed round led by Global Founders Capital and Credo Ventu

AssemblyAI is a leading speech AI platform providing APIs for transcription, speaker diarization, sentiment analysis, topic detection, and audio intelligence at enterprise scale. Founded in 2017 and h

Authologic is a Warsaw-based unified digital identity verification platform — providing KYC (Know Your Customer) and AML (Anti-Money Laundering) compliance automation for financial services, gaming, g

Axle is an insurance connectivity platform that provides APIs enabling businesses to instantly verify insurance coverage and access policy data by connecting directly to insurance carrier systems. Bus

Balance is a New York City-based B2B payments and checkout platform — backed by Y Combinator (W20) with $436.6 million in total funding from Viola Credit, Lightspeed Venture Partners, Avid Ventures, R

BrowserStack is a Mumbai, India-based cloud software testing platform — bootstrapped to profitability and backed with $253 million in total funding including a $200 million Series B in 2021 led by Bon

Bruno is an open-source API client and testing tool — a lightweight, offline-first, git-friendly alternative to Postman and Insomnia — enabling developers to explore, test, and document APIs with coll

CaptivateIQ is a no-code incentive compensation management (ICM) platform that enables sales operations and finance teams to design, automate, and manage sales commission plans — replacing spreadsheet

Checkout.com is a global payment processing platform providing enterprise-grade payment APIs, gateway, and acquiring services for large-scale merchants and platforms. Founded in 2012 and headquartered

Checkr is a modern background check platform that uses machine learning to automate employment screening, helping companies make faster, fairer, and more compliant hiring decisions. Founded in 2014 an

Clerk is an authentication and user management company that provides developers with pre-built sign-up, sign-in, and user profile components alongside a complete backend API for identity management. A

Cohere is an enterprise AI platform company providing large language model APIs, embedding models, and AI deployment infrastructure for enterprise applications — competing with OpenAI and Anthropic in

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.co (now Daily) is a real-time video and audio API platform enabling developers to embed high-quality video calls, audio conferencing, and live streaming into web and mobile applications without

Datafold is a data observability and data quality testing platform that helps data engineering teams automatically detect data quality regressions, schema changes, and anomalies in their data pipeline

Decentro is an Indian banking-as-a-service (BaaS) API platform enabling fintech companies, enterprises, and technology startups to embed financial services into their products — bank accounts, payment

Deepgram is a speech AI company providing fast, accurate, and cost-efficient speech-to-text and audio intelligence APIs built on proprietary end-to-end deep learning models. Founded in 2015 and headqu

Dots is a San Francisco-based payout infrastructure company providing a multi-channel API for marketplaces, gig platforms, and creator economy companies to pay their sellers, contractors, and creators

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 B2B fintech company providing an integrated platform for African businesses to automate payables, receivables, and corporate expense management — enabling companies to pay supplier

Exa is a next-generation AI search engine and API designed specifically for AI agents and developers — providing LLM-optimized web search that returns clean, structured content from web pages rather t

FarmLogs is a farm management software platform acquired by Bushel (an agricultural supply chain software company) in 2020 — providing crop farmers and agricultural operations with digital tools to tr

Feedonomics is a Los Angeles-based product feed management and optimization platform — acquired by BigCommerce (NASDAQ: BIGC) in 2021 for $145 million — that helps e-commerce brands and retailers synd

Fern is a New York-based API tooling company that automatically generates multi-language SDKs and API documentation from OpenAPI specifications — enabling API companies to publish high-quality client

Finch is a universal employment API providing a single integration point for HR, payroll, and benefits data from hundreds of employment systems — Gusto, ADP, Workday, QuickBooks Payroll, Rippling, and

Finix is a payments infrastructure company enabling software platforms, SaaS companies, and marketplaces to become their own payment facilitators — processing payments directly rather than through thi

Fintoc is a Santiago, Chile-based open banking API company that enables online businesses to accept instant account-to-account payments directly from customers' bank accounts — bypassing credit card n

Flagsmith is an open-source feature flagging and remote configuration platform that enables engineering teams to deploy code continuously and control feature releases, A/B tests, and configuration cha

Flex is a United States-based HSA/FSA payment infrastructure platform — backed by Y Combinator (S23) with $18 million in total funding including a $3.2 million seed in September 2024 from Y Combinator

FlutterFlow is a no-code and low-code app builder that enables users to create native iOS, Android, and web applications by visually designing screens, connecting backend services (Firebase, Supabase,

Flutterwave is a pan-African payments technology company building the infrastructure enabling businesses to make and accept payments across Africa and beyond. Founded in 2016 in San Francisco with ope

Formance is a Paris, France-based open-source financial infrastructure company — backed by Y Combinator with $21 million raised in a Series A in January 2025 co-led by PayPal Ventures and Portage Vent

GitHub Actions is Microsoft's CI/CD (continuous integration/continuous deployment) and workflow automation platform built natively into GitHub — enabling developers and DevOps teams to automate softwa

GoCardless is a global bank payment network specializing in recurring bank-to-bank payments via direct debit, enabling businesses to collect subscription fees, invoices, and recurring charges directly

H2O.ai is an open-source machine learning and AI platform company providing automated machine learning (AutoML), model explainability, enterprise AI application development, and generative AI tools —

Heron Data is a financial data intelligence platform providing instant categorization and enrichment of transaction data for fintech companies, lenders, and financial services applications. Founded in

Hightouch is a San Francisco-based data activation and composable CDP (Customer Data Platform) platform — backed with approximately $220 million in total funding including an $80 million Series C in F

Hoppscotch is an open-source API development and testing platform — providing a web-based, lightweight alternative to Postman and Insomnia for building, testing, and documenting REST, GraphQL, WebSock

Hugging Face is the leading AI model hosting and collaboration platform and the creator of the Transformers library — providing open-source infrastructure for sharing, discovering, and deploying machi

Humaans is a modern HRIS (Human Resources Information System) and employee data platform designed for fast-growing technology companies that have outgrown spreadsheets and need a clean, API-first empl

Hyperspell is an AI document intelligence company that combines AI-assisted writing with structured knowledge management to help teams create and maintain complex long-form documents more efficiently.

Increase is a San Francisco-based banking infrastructure company providing direct-access banking APIs to technology companies — enabling fintechs, neobanks, payroll platforms, and embedded finance pro

Infinia is a Montevideo, Uruguay-based account-to-account (A2A) payments infrastructure company — backed by Y Combinator (W23) with $500,000 in funding from G2 Momentum Capital, Tekton Ventures, YC, D

Insomnia is an open-source API development and testing platform that provides developers with a powerful client for designing, debugging, and testing REST, GraphQL, SOAP, and WebSocket APIs — offering

Jestor is a no-code/low-code platform that enables businesses to build custom internal tools, automate workflows, and manage structured data without writing software — providing a visual interface to

Jitsu is a San Francisco-based open-source data integration platform enabling data engineers to build real-time event data pipelines that collect, transform, and route user behavior events from web an

Kombo is a Berlin-based unified HR integration API that enables B2B software companies to integrate with 100+ HR, ATS (applicant tracking systems), and payroll systems through a single standardized AP

Kong is an enterprise API management and service connectivity platform providing an API gateway, service mesh, and developer portal for organizations managing hundreds of microservices and APIs. Found

Lendflow is an embedded lending infrastructure platform that enables software companies to integrate credit products — business loans, lines of credit, revenue-based financing — directly into their ex

Lightspeed Commerce is a cloud-based point-of-sale and commerce platform serving restaurants, retail stores, and golf clubs with POS, payments, inventory management, and ecommerce capabilities integra

Malga is a São Paulo-based payment orchestration platform — backed by Y Combinator with $10.3 million raised including a $5.55 million Series A led by CV iDEXO and Costanoa in February 2025 — enabling

Marketo is a leading B2B marketing automation platform now part of Adobe — providing email marketing, lead management, account-based marketing (ABM), consumer marketing automation, and revenue attribu

Mistral AI is a French artificial intelligence company building and commercializing high-performance open and proprietary large language models, positioning itself as Europe's leading AI foundation mo

Mito is a New York-based developer tools company providing a JupyterLab spreadsheet extension that automatically generates Python code as users edit data — enabling Excel-proficient data analysts to a

Modern Treasury is a payments operations platform providing API infrastructure for moving money, reconciling transactions, and managing ledger entries at scale. Founded in 2018 and headquartered in Sa

Mono is a Lagos-based fintech company providing open banking APIs that enable African businesses to connect with their customers' financial accounts — offering account connectivity (read customer bank

MuleSoft is an integration platform-as-a-service (iPaaS) that enables enterprises to connect applications, data sources, and APIs across cloud and on-premises systems — providing the integration middl

n8n is a workflow automation platform that differentiates itself in the crowded automation market through its open-source model, deep AI integration, and flexibility for technical users. While Zapier

Nango is a San Francisco-based integration infrastructure platform — backed by Y Combinator (W23) with $1.2 million in annual revenue in 2024 — providing developers and engineering teams with a unifie

NanoNets is an AI-powered document processing platform that automates data extraction from invoices, receipts, purchase orders, and other unstructured documents. Founded in 2017 and headquartered in S

Nash is a last-mile delivery orchestration platform that enables retailers, restaurants, and logistics companies to manage on-demand delivery through a single integration connecting to a network of de

NewsCatcher is a London-based web data company providing enterprise news and web data APIs — processing 1.5 million articles daily from 140,000+ sources across 60+ languages — serving hedge funds, fin

Nium is a global fintech company providing real-time payment infrastructure for banks, financial institutions, and platforms operating across international markets. Founded in 2014 in Singapore and he

OpenAI is a San Francisco-based artificial intelligence company developing and deploying large-scale AI systems — including GPT-4o, o1 reasoning models, DALL-E 3 image generation, Sora video generatio

OpenAI Platform is the developer API platform of OpenAI — providing programmatic access to OpenAI's large language models (GPT-4o, o1, o3, Whisper, DALL-E, Sora) and AI tools through a REST API that d

Palenca is a Mexico City-based fintech API company providing payroll data connectivity across Latin America — enabling fintechs, banks, and financial institutions to access employment and income data

Paw is a powerful REST, GraphQL, and HTTP API testing client for macOS, designed for developers who need a native, feature-rich alternative to web-based tools like Postman. Founded and developed as an

PayCaddy is a Panama City, Panama-based Banking as a Service (BaaS) platform — backed by Y Combinator (W22) with $4.3 million raised from AAF Management, Cathexis Ventures, Kube VC, Rebel Fund, and So

Paystack is a payments technology company enabling African businesses to accept payments from customers worldwide through cards, bank transfers, and mobile money. Founded in 2015 in Lagos, Nigeria by

Pier is a San Francisco-based credit-as-a-service API platform — backed by Y Combinator (W23) with $2.4 million in seed funding from Liquid 2 Ventures, YC, ACME, Horizon Ventures, and angels in early

Plaid is a financial data infrastructure company that provides the API layer connecting financial applications to bank accounts and financial data. Founded in 2013 by Zach Perret and William Hockey, P

Planful is a Redwood City, California-based cloud financial planning and analysis (FP&A) platform providing mid-market and enterprise finance teams with integrated budgeting, forecasting, reporting, c

Postman is the world's leading API development platform — providing the tools that 30 million+ developers use to design, build, test, document, and monitor APIs throughout the software development lif

Prequel is a photo and video editing app for iOS and Android that provides film-like aesthetic filters, cinematic presets, analog film emulations, and AI-powered editing tools that transform smartphon

Primer is a no-code payment orchestration platform allowing enterprise merchants to manage their entire payment stack — processors, fraud tools, 3DS providers, and payment methods — through a visual w

Productive.io is a professional services automation (PSA) platform designed for agencies, consulting firms, and software development studios — combining project management, resource planning, time tra

Propexo is a Boston, Massachusetts-based commercial real estate API platform — backed by Y Combinator (W23) with $10 million in total funding including a $3.3 million seed from Prudence, Fifth Wall, Y

QuestDB is a London, United Kingdom-based open-source time-series database — backed by Y Combinator (W20) with $14.4-18 million in total funding including a $12 million Series A in November 2021 from

RapidAPI is the world's largest API marketplace and developer hub, providing a platform where developers discover, connect to, and manage thousands of public and private APIs through a unified interfa

Rapyd is a global fintech-as-a-service platform providing payment infrastructure, issuing, banking, and compliance services that allow businesses to embed financial capabilities into their products ac

Razorpay is India's leading full-stack payments and business banking platform, enabling businesses of all sizes to accept online payments, manage payouts, and access banking services through a single

Regie.ai is a San Francisco-based AI sales engagement platform providing enterprise B2B sales teams with generative AI for prospecting email creation, sequence personalization, and sales content gener

Release is a United States-based Environments as a Service (EaaS) platform — backed by Sequoia Capital with seed funding — providing development teams with ephemeral, test, QA, and staging environment

Replicate is a San Francisco-based cloud platform that makes it easy to run and deploy machine learning models through a simple API — providing access to thousands of pre-trained open-source models (S

Rollbar is a real-time error monitoring and debugging platform that captures software exceptions, stack traces, and user context from web and mobile applications — enabling developers to identify, pri

Routable is an accounts payable and mass payments automation platform helping businesses streamline vendor payments, contractor payouts, and reimbursements. Founded in 2017 and based in San Francisco,

Safepay is a Karachi, Pakistan-based payment processing company and Pakistan's first Y Combinator graduate fintech — backed by Y Combinator (W20) with $5.5 million in total funding from Stripe, Global

Scoro is a business management platform designed for professional services companies — agencies, consultancies, and service firms — providing project management, resource planning, time tracking, bill

Shippo is a multi-carrier shipping and fulfillment API platform enabling e-commerce businesses, developers, and platforms to compare rates, purchase labels, and track shipments across USPS, UPS, FedEx

Sivo is an embedded lending infrastructure platform that enables fintech companies and financial services startups to offer credit products to their customers without building their own loan originati

Slash is a Los Altos-based fintech company providing comprehensive financial services and corporate cards for high-spending businesses — offering global payments, programmable corporate cards, real-ti

Slope is a B2B buy-now-pay-later (BNPL) and net terms payment platform enabling suppliers to offer flexible payment terms to business customers while receiving payment upfront. Founded in 2021 and hea

SnapTrade is a brokerage API integration platform providing read and write access to retail brokerage accounts at 20+ major brokerages — enabling fintech companies and investment apps to connect to th

Snyk is a developer security platform that integrates security testing directly into the developer workflow — scanning code, open-source dependencies, container images, and infrastructure-as-code for

Socotra is a cloud-native insurance core platform (policy administration system) providing policy management, billing, claims, and distribution tools for insurance carriers and managing general agents

Stacker is a data journalism and content marketing platform that produces fact-based, data-driven news stories using publicly available datasets — generating thousands of articles annually about topic

Stark Bank is a São Paulo, Brazil-based open banking API platform and digital business bank — backed by Y Combinator (W20) with $58.2 million in total funding including a $45 million Series B in April

StayNTouch is a cloud-based property management system (PMS) for hotels and resorts, providing front desk operations, reservations, housekeeping management, and guest engagement tools through a modern

Strapi is a Paris, France-based open-source headless CMS company — backed with $49 million in total funding including a $31 million Series B in June 2022 led by CRV with Flex Capital, Index Ventures,

Superwall is a San Francisco-based mobile subscription paywall platform that enables iOS and Android app developers to remotely configure, test, and optimize their in-app subscription paywalls without

Swagger (now part of SmartBear Software) is the world's most popular API development toolset — including Swagger UI (interactive API documentation), Swagger Editor (browser-based OpenAPI spec editor),

Swift is a San Francisco-based embedded finance platform — backed by Y Combinator (W24) with $2.34 million raised from 27 investors — enabling online merchants and e-commerce platforms to embed financ

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 Chicago, Illinois-based cloud communications platform — privately held with $60+ million raised from investors including Salesforce Ventures, Felicis Ventures, and ICONIQ Growth — providin

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 United Kingdom-based web-to-desktop application platform — backed by Y Combinator with $150,000 in total funding from Y Combinator and Frontline Ventures — providing developers with inf

TrueLayer is a European open banking platform providing payment initiation and account data APIs that allow businesses to accept bank payments, verify account ownership, and access financial data with

Union54 is a Lusaka, Zambia-based fintech company — backed by Y Combinator — operating ChitChat, an integrated messaging and digital payments platform that combines secure instant messaging with USD d

Unit is a banking-as-a-service platform enabling fintech companies and software businesses to embed banking, card, and payment products into their applications through a single API. Founded in 2019 an

Versori is a London-based agentic integration platform enabling businesses to build, deploy, and manage custom software integrations and automation workflows through a no-code, AI-powered environment

Wasp is a Zagreb, Croatia-based full-stack web development framework — backed by Y Combinator (W21) with $5.2 million in total funding including a $3.7 million round in late 2024 led by HV Capital wit

Whalesync is a San Francisco-based no-code data synchronization platform providing bi-directional real-time sync between popular business tools — Airtable, Notion, HubSpot, Webflow, PostgreSQL, and ot

xPay is a San Francisco-based international billing operations platform for SaaS companies — handling the complexity of cross-border subscription billing, sales tax and VAT compliance, and payment loc