One GTM API for contacts and companies - Waterfall.io API Documentation

Waterfall brings together 30+ data vendors through one B2B data API. Find people at target accounts, match emails to business profiles, find contact details, and check whether existing contacts have changed jobs. Use it to build signup enrichment, prospecting, and CRM workflows with the data your team needs. About Waterfall explains how it fits into your stack.

Explore use cases

Start with a signup, target account, or CRM record and see the workflow.

Use with agents

Run a lookup with an agent or build Waterfall into your application.

Evaluate Waterfall

Compare useful results, match quality, and cost on your own records.

Make your first request

Launch a contact enrichment job and retrieve its result.

Already know what you want to build? Choose an API to compare the inputs, results, and availability of each capability.

What do you want to build?

Your task	Start here
See who is behind a signup email	Signup enrichment
Find people at your target accounts	Account prospecting
Fill gaps in contact and company records	CRM enrichment
Check where existing contacts work	Job changes
Check an email before outreach	Email verification
Identify companies visiting your website	Website company identification

How the API works

Send requests to https://api.waterfall.io with your API key in the x-api-key header. Authentication covers access and key management. Prospector and the contact, phone, and company enrichment APIs return a job_id. Use the matching Finder to retrieve the result, or provide a webhook_url to receive it. Search and verification APIs return results in the same request. The API selection guide lists the response pattern and availability for each capability. Every reference page shows the supported inputs and outputs. Use Usage Tracking to read returned costs, and Account Reporting for usage across a date range. For API access, pricing, or help choosing the right workflow, talk to the Waterfall team. Common product and integration questions are covered in the FAQ.