69 Best Application Programming Interface Api Startups to Watch in 2025

The Definitive Seedtable Ranking of Application Programming Interface Api Startups

We track 71,000+ companies and rank them dynamically using our Seedtable Score – a score that uses quantitative and qualitative data points to signal the momentum behind a company. We then monitor the list manually leveraging our expertise as founders and investors.

There are 356 start-ups with an aggregate funding of $10.3b. The average funding per company in this subset is $148.6m.

Last update to the database: Feb 18, 2025. See changelog.

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4

Funding Rounds

$106.4m

Money raised

Moralis is a Web3 development platform.

6

Funding Rounds

$95.0m

Money raised

ClimaCell is a Boston-based weather intelligence platform for automated weather predictions.

Location:

Key people:

8

Funding Rounds

$274.7m

Money raised

Sisense is a software company offering a platform for data analysts and data engineers to transform data into actionable business insights.

5

Funding Rounds

$241.5m

Money raised

Hasura is a software and development tools company, offering tools for developers to simplify application development.

Location:

Key people:

1

Funding Rounds

$1.2m

Money raised

Zapier is an American for-profit corporation and a web-based service that allows end users to integrate the web applications they use.

Location:

Key people:

5

Funding Rounds

$37.7m

Money raised

42Crunch is an enterprise API security platform with integrated services, including an API firewall, to discover and remediate API security vulnerabilities.

Location:

Key people:

5

Funding Rounds

$433.0m

Money raised

Postman is a San Francisco-based software company offering an API development environment.

2

Funding Rounds

$146.0m

Money raised

Unifonic is a Saudi-based cloud communication startup.

Location:

Key people:

2

Funding Rounds

$2.0m

Money raised

Plivo is a cloud-based communications platform as a service (CPaaS) company headquartered in San Francisco, California. The company allows software developers to integrate phone calls, text messages, and other communication functions into their applications using its web service APIs.

20

Funding Rounds

$363.4m

Money raised

Contentful's platform helps teams deliver digital experiences faster with an API-first approach.

Location:

Key people:

2

Funding Rounds

$3.0m

Money raised

Fortress Identity is a Miami-based cybersecurity developer offering multi-factor authentication with biometrics inherence factors to secure iOS and Android applications, active directory environments and Citrix applications.

4

Funding Rounds

$68.4m

Money raised

PolyAI is a company building an enterprise conversational platform with AI-generated voice assistants to improve customer experience.

Location:

Key people:

5

Funding Rounds

$90.0m

Money raised

Strapi is a company offering an open-source headless content management system (CMS).

9

Funding Rounds

$462.2m

Money raised

Algolia is a company designing and building search and discovery API for websites and mobile apps. It participated in the W14 cohort of Y Combinator.

Location:

Key people:

7

Funding Rounds

$207.3m

Money raised

Replit is a San Francisco-based IDE and software development environment company making a browser application platform for coding in over fifty programming languages.

Location:

Key people:

3

Funding Rounds

$46.8m

Money raised

EVEN Financial offers a B2B2C API to help connect financial institutions to consumers, and connect consumers to personalized financial products.

7

Funding Rounds

$218.1m

Money raised

SendBird is a developer of a messaging API for mobile applications and websites.

Key people:

7

Funding Rounds

$281.0m

Money raised

Salt Security is a Palo Alto, California-based protection platform for APIs and associated API integrations.

Key people:

2

Funding Rounds

$35.0m

Money raised

Stardust is a company that develops solutions for gaming in the metaverse.

Key people:

7

Funding Rounds

$97.8m

Money raised

Directly is a San Francisco-based developer of artificial intelligence systems of customer experience and chatbots founded by Antony Brydon, Jean Tessier and Jeff Patterson.

6

Funding Rounds

$276.5m

Money raised

Crunchbase is company that offers an online platform for discovering information related to private and public businesses.

6

Funding Rounds

$37.7m

Money raised

MachineMetrics is a developer of industrial IoT analytics and a machine monitoring platform.

Key people:

3

Funding Rounds

$313.0m

Money raised

Flatiron Health is a startup that organizes real-time oncology data to help cancer patients and doctors.

6

Funding Rounds

$23.7m

Money raised

Symbl is an API platform for businesses looking to deploy conversational intelligence.

Location:

Key people:

7

Funding Rounds

$272.5m

Money raised

Rapid API is a software company specializing in developing a platform for application programming interfaces.

4

Funding Rounds

$118.2m

Money raised

Railsr, formerly Railsbank, is a London-based open-API banking and compliance platform that gives regulated and un-regulated companies access to global bankings.

4

Funding Rounds

$3.2m

Money raised

MonkeyLearn is an artificial intelligence data analysis and visualization platform.

6

Funding Rounds

$9.8m

Money raised

Facial recognition company Kairos today announced the alpha release of the Kairos Protocol, a biometric verification system for cryptocurrency transactions.

3

Funding Rounds

$13.9m

Money raised

Corsha provides API security software that aims to prevent network attacks through multi-factor authentication for APIs.

3

Funding Rounds

$220.0m

Money raised

Noname Security is a Palo Alto, California-based cybersecurity and network security company developing products to protect APIs.

Industries:

Key people:

5

Funding Rounds

$162.5m

Money raised

A company offering a communications platform allows developers to quickly build features that connect to every email, calendar, and contacts provider in the world.

5

Funding Rounds

$2.3m

Money raised

An app that aggregates social media data to produce a real-time map of sickness.

1

Funding Rounds

$8.0m

Money raised

Uphold (formerly Bitreserve) is a cloud-based digital money platform. Users can buy, hold, convert and transact across currencies and commodities, including cryptocurrencies.

5

Funding Rounds

$108.1m

Money raised

AssemblyAI is a speech AI company developing AI models capable of transcribing and understanding human speech.

5

Funding Rounds

$48.1m

Money raised

Spire is a company developing tags that provide health tracking including respiration, sleep, stress, activity, and pulse rate.

Location:

Key people:

5

Funding Rounds

$373.0m

Money raised

Gupshup is an AI-powered messaging platform that integrates with communication software and protocols for commerce, marketing, and support applications.

5

Funding Rounds

$167.6m

Money raised

Kong (formerly Mashape) is a San Francisco-based company that offers open source microservice API gateway.

9

Funding Rounds

$57.5m

Money raised

DrChrono is a company providing EHR, Practice Management, and Revenue Cycle Management Solution APIs. It participated in the W11 cohort of Y Combinator.

Key people:

8

Funding Rounds

$132.0m

Money raised

Practice Fusion is a San Francisco-based developer of electronic health record and medical practice management software.

6

Funding Rounds

$2.8b

Money raised

Sinch offers programmable SMS, voice, video, and verification tools.

1

Funding Rounds

$2.0m

Money raised

Cardiogram is a company building a personal healthcare assistant, using Deep Learning to turn consumer wearables into continuous health monitors. Cariogram can now detect 4 medical conditions Sleep Apnea, High Blood Pressure, Atrial Fibrillation, and Diabetes.

Location:

Key people:

4

Funding Rounds

$20.4m

Money raised

Stoplight is an Austin, Texas based company developing an API design and documentation platform.

Location:

Key people:

2

Funding Rounds

$20.4m

Money raised

A patient connection and relationship management company, using artificial intelligence-enabled technology to drive more meaningful patient-doctor engagements while improving care utilization and pathways.

Location:

Key people:

5

Funding Rounds

$33.9m

Money raised

A company building an identity resolution & insights platform

7

Funding Rounds

$430.8m

Money raised

AppDirect is a company providing an end-to-end cloud commerce platform for businesses.

Location:

Key people:

7

Funding Rounds

$86.8m

Money raised

Sanity is a software company offering a customizable headless content management system (HCMS).

7

Funding Rounds

$134.0m

Money raised

U.S-based company providing cloud infrastructure for global software and hardware development and deployment.

2

Funding Rounds

$15.5m

Money raised

Moesif is a Caifornia-based company providing API analytics and tools.

1

Funding Rounds

$5.6m

Money raised

Firebase is a mobile and web application development platform. It was founded in 2011 and acquired by Google in 2014. It is located in San Francisco, California.

3

Funding Rounds

$25.0m

Money raised

SmartBear Software is a company developing tools for various software development and API management tasks.

7

Funding Rounds

$268.8m

Money raised

TruePill is a US-based company providing pharmacy product deliveries.

1

Funding Rounds

$2.4m

Money raised

Bloom API is a healthcare company focused on communication practices.

4

Funding Rounds

$115.4m

Money raised

Lithic is a financial technology company that builds payments infrastructure for businesses and consumers.

Key people:

2

Funding Rounds

$80.0m

Money raised

Traceable is an API security software developed to protect application infrastructures.

3

Funding Rounds

$5.3m

Money raised

An insurance technology company offering a platform for healthcare organizations to access health insurance data to improve their ability to bring new products and services to market.

6

Funding Rounds

$17.6m

Money raised

Mailjet is an email services provider.

3

Funding Rounds

$2.9m

Money raised

Speechly is a Helsinki-based developer of a voice interface API for web and mobile applications.

Location:

Key people:

7

Funding Rounds

$35.3m

Money raised

NewsWhip is a predictive media monitoring tool founded in 2011 by Paul Quigley.

8

Funding Rounds

$327.0m

Money raised

FalconX is a blockchain, cryptocurrency, and fintech-focused brokerage and digital asset trading platform.

Key people:

1

Funding Rounds

$8.5m

Money raised

Bitquery is a ​​blockchain data company that offers a full set of APIs and analytics tools to democratize data access and solve pain points associated with on-chain data.

4

Funding Rounds

$22.1m

Money raised

Wyre is a San Francisco-based developer of a payment platform on blockchain founded by Michael Dunworth and Ioannis Giannaros.

4

Funding Rounds

$70.0m

Money raised

Coterie is an API-based commercial business insurance provider that updates policy changes in real-time.

Location:

Key people:

6

Funding Rounds

$42.3m

Money raised

Pliant is a company offering a workflow orchestration and infrastructure automation platform.

5

Funding Rounds

$24.1m

Money raised

BetterDoctor, a technology company, delivers provider directory data and has a database that can be accessed through a responsive API.

Key people:

7

Funding Rounds

$99.4m

Money raised

Lob is a company developing and building APIs for automating mail and customer communications with print media. It participated in the S13 cohort of Y Combinator.

Location:

Key people:

1

Funding Rounds

$8.0m

Money raised

StepZen is a San Jose, California-based software as a service (SaaS) company offering a GraphQL API development service.

Key people:

2

Funding Rounds

$12.8m

Money raised

Developer of a healthcare platform designed to simplify personal health data. The company's platform captures data from clinical and remote-monitoring devices, sensors, fitness equipment, and patient-wellness applications, enabling users to access, manage and utilize device-generated data.

3

Funding Rounds

$17.0m

Money raised

Boost Insurance is a New York-based insurance technology and infrastructure-as-a-service company founded in 2017.

Key people:

3

Funding Rounds

$8.1m

Money raised

Apiax transforms complex regulations into digital compliance rules, which are constantly up-to-date and verified, accessible via an API.

Key people:

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