Niche — API

API-first startups

API-first companies and integration platforms turning capability into a paid endpoint.

RS
Resend
Email API for developers — built on React.
Dev Tools·Series A
MT
Modern Treasury
Payment ops infrastructure for B2B businesses.
Fintech·Series C
IN
Increase
ACH, wires, real-time payments, and checks via one API.
Fintech·Series B
N8
n8n
Workflow automation for technical people.
Open Source·Series B
FW
Fireworks AI
Productive AI platform with the fastest inference.
AI·Series B
IF
Infisical
The open-source secret manager.
Open Source·Seed
RT
Retool
Build internal tools, remarkably fast.
SaaS·Series C
RM
ReadMe
Beautiful, personalized developer hubs.
SaaS·Series C
CO
Column
The first developer-first bank.
Fintech
ST
Stytch
Modern user authentication for developers.
Dev Tools·Series B
AP
Apidog
All-in-one API design, testing, and documentation.
Dev Tools·Series A
PM
Permit.io
Authorization as a service.
Dev Tools·Seed
TD
tldraw
Build whiteboards into your product.
Open Source·Seed
UK
Unkey
Open-source API authentication and authorization.
Open Source·Seed
DI
Directus
The instant headless CMS + data platform.
Open Source·Series A
PT
Patch
Climate action infrastructure.
Other·Series B
SU
Sure
Embedded insurance infrastructure.
Fintech·Series D
PR
PhotoRoom
AI image editing for commerce.
AI
RE
Relay
Business banking built for visibility.
Fintech
SF
Silverflow
Card payment processing for the cloud era.
Fintech
CL
Cal.com
Open-source scheduling for everyone
SaaS·Series A
PT
Pitch
Collaborative presentation software for teams
SaaS·Series B
NV
Novu
Open-source notification infrastructure for developers
Dev Tools·Series A
ST
Stainless
Quality SDKs for your REST API
Dev Tools·Series A
BB
Browserbase
Headless browser infrastructure for AI agents
Dev Tools·Seed
EX
Exa AI
Neural search API designed for AI applications
AI·Seed
FC
Firecrawl
Web scraping API built for LLMs
Dev Tools·Seed
CH
Chroma
Open source AI-native embedding database
AI·Seed
LK
LiveKit
Open source WebRTC and real-time AI infrastructure
Dev Tools·Series B
NG
Nango
Open source platform for product integrations
Dev Tools·Seed
RA
Recall AI
Universal API to capture data from any meeting
AI·Series A
AP
Activepieces
Open source business automation platform
SaaS·Seed
MR
Merge
Unified API for HR, ATS, CRM, and accounting integrations
SaaS·Series B
PF
Prefect
Workflow orchestration for data and ML teams
Dev Tools·Series C
BN
BentoML
Unified AI model serving and deployment framework
AI·Series A
LP
Lepton AI
Pythonic cloud for AI applications
AI·Series A
SP
Speakeasy
Enterprise-grade SDKs and API tooling
Dev Tools·Series A
ZP
Zuplo
Programmable API gateway for developer teams
Dev Tools·Seed
HP
Hoppscotch
Open source API development ecosystem
Dev Tools·Seed
SG
Semgrep
Code security and static analysis at dev speed
Dev Tools·Series C
SC
Scalar
Beautiful open source API references and clients
Dev Tools·Bootstrapped
RW
Rows
The spreadsheet with superpowers and integrations
SaaS·Series B
PY
Pennylane
AI-powered accounting software for SMEs
Fintech·Series C
AL
AnythingLLM
The all-in-one open source AI desktop application
AI·Bootstrapped
AG
Agno
Open source framework for multi-modal AI agents
AI·Seed
BM
Beam
Serverless infrastructure for AI and ML workloads
AI·Seed
TW
Twenty
Open source CRM built for modern teams
SaaS·Seed
TB
Typebot
Open source chatbot builder with powerful logic
SaaS·Bootstrapped
RQ
Requestly
Browser extension and proxy for API mocking and testing
Dev Tools·Seed
OS
OpenStatus
Open source monitoring and status page platform
Dev Tools·Bootstrapped
OL
Ollama
Run large language models locally
AI·Bootstrapped
OR
OpenRouter
Unified API for every major LLM
AI·Seed
PK
Portkey
AI gateway and LLMOps platform for production
AI·Series A
VA
Vapi
Voice AI infrastructure for developers
AI·Seed
AS
AssemblyAI
Audio intelligence API for developers
AI·Series C
AX
Axiom
Serverless log management and event data platform
Dev Tools·Series A
KN
Knock
Flexible notification infrastructure for developers
Dev Tools·Series A
CO
Courier
Multi-channel notifications API for product teams
Dev Tools·Series B
BB
Budibase
Low-code platform for building internal apps fast
Dev Tools·Series A
WG
WunderGraph
API integration platform and GraphQL federation
Dev Tools·Seed
SM
Stitch
Payments and financial data API for Africa
Fintech·Series A
ES
Escape
API security testing and DAST for developers
Dev Tools·Series A
GG
Gorgias
Helpdesk built specifically for ecommerce brands
SaaS·Series D
PT
Patch
Carbon removal and climate project infrastructure
SaaS·Series A
MX
Mux
Video infrastructure API for developers
Dev Tools·Series C
MT
Mastra
The TypeScript framework for building AI agents
Dev Tools·Seed
GG
Gigs
Launch a mobile service that runs itself
SaaS·Series B
EN
Enode
One API to connect and control any energy device
SaaS·Series A
SD
Stedi
The programmable healthcare EDI clearinghouse
SaaS·Series C
SL
Slash
Business banking built for internet entrepreneurs
Fintech·Series A
FN
Fun
Global stablecoin payments for modern fintechs
Fintech·Series A
CH
Chromatic
Visual testing and review for UI components
Dev Tools·Series B
SC
Shortcut
Project management software that developers love
SaaS·Series B
LC
LanceDB
Multimodal vector database for AI
Open Source·Series A
MI
MinIO
High-performance S3-compatible object storage
Open Source·Series B
MM
Mattermost
Open source Slack alternative for developers
Open Source·Series C
FS
Flagsmith
Feature flags and remote config for any platform
Open Source·Series A
UL
Unleash
The enterprise open source feature management solution
Open Source·Series B
SL
Saleor
Open source GraphQL-first e-commerce platform
Open Source·Series A
BB
Bytebase
Database DevOps and CI/CD for teams
Open Source·Series A
OW
Open WebUI
ChatGPT-style UI for any LLM
Open Source·Seed
LL
LiteLLM
Call 100+ LLMs with one interface
Open Source·Seed
OL
OpenLIT
Open source LLM observability and evaluation
Open Source·Bootstrapped
FW
Flowise
Drag-and-drop UI to build LLM flows
Open Source·Seed
LF
Langflow
Visual framework for building multi-agent AI apps
Open Source·Series A
BR
Bruno
Open source IDE for exploring APIs
Open Source·Bootstrapped
OT
Outline
Fast, collaborative, wiki-style knowledge base
Open Source·Series A
ME
Memos
Lightweight, self-hosted memo hub
Open Source·Bootstrapped
GT
GlitchTip
Open source error tracking
Open Source·Bootstrapped
OO
OpenObserve
Open source observability with 140x lower storage costs
Open Source·Seed
OB
OpenBB
Open source investment research terminal
Open Source·Series A
SA
SuperAgent
Open source AI agent platform
Open Source·Seed
PS
Postal
Full-featured open source mail delivery server
Open Source·Bootstrapped
MT
Mautic
Open source marketing automation platform
Open Source·Bootstrapped
PE
Peach
API-first loan management platform
Fintech
NG
Ngrok
Ngrok
Dev Tools
CA
Cake AI
Cake AI
AI
FI
Finch
Finch
Fintech
PI
Pin
AI-powered recruitment platform
SaaS
PA
Paragon
Embedded integration platform for SaaS
Dev Tools
FI
Finmid
Embedded financing solutions for SMBs
Fintech
AA
Alloy Automation
Embedded iPaaS platform for product teams
Dev Tools
AR
Array
Embedded finance products platform
Fintech
PU
Pulse
Production-grade unstructured document extraction
Dev Tools
PA
Parafin
Embedded finance infrastructure for SMBs
Fintech
PL
Pliant
Corporate card platform
Fintech
ST
StackOne
Ship hundreds of integrations in days
Dev Tools
LE
Leen
Unified API for security tools and data
Dev Tools
RU
Rutter
Connecting the world's business data
Fintech
RA
Radical AI
aAccelerating materials R&D
AI
RI
Rillet
The AI-native ERP
Fintech
PY
Pylon
The support platform built for B2B
SaaS
ME
Merge
One API to 100s of integrations
Dev Tools
SY
Syenta
High-performance semiconductor chips
AI
IN
Inkeep
AI support you can trust
AI
FA
Farel
Airline on autopilot
SaaS
SY
Symbiotic
Universal staking platform
SaaS
PO
Polars
DataFrames for the new era
Dev Tools
RE
Reducto
Document ingestion API
Dev Tools
FL
Flow
The Agile Requirements Management Platform
AI
IN
Inference
Inference
Dev Tools
PO
Poolside
Frontier research to operational intelligence
AI
SP
Speakeasy
Generate MCP servers & SDKs from OpenAPI
Dev Tools
LE
Legend
Your gateway to decentralized finance
SaaS
LA
Langdock
The AI platform for your company
AI
LG
LGND
ChatGPT for the Earth
AI
JU
Junction
Modernizing healthcare infrastructure
SaaS
ME
Medra
Physical AI integrated in your lab
AI
TS
Truffle Security
Unearth your secrets
Dev Tools
MY
Mytra
Automated robotic storage
AI
RU
RunPod
Deploy full-stack AI applications
Dev Tools
AN
Anvil
Document SDK for product teams
Dev Tools
BO
Boxo
Turn apps into Super Apps
Dev Tools
DE
Defacto
B2B lending platform
Fintech
ST
Stuut
Turn your orders into cash
Fintech
KE
Kernel
Browser infra for web agents and automations
Dev Tools
SU
Supermemory
Universal memory API for AI apps
Dev Tools