Documentation
Introduction
What the Furnace Client API is and where to start.
Furnace runs personalized cold email campaigns. Create campaigns, add people, launch sending, and handle replies — all from your own code.
Furnace sends sequences of personalized emails to a list of people, from one or more of your inboxes. It waits between steps and can branch based on how people reply.
What you can build
Campaigns
Create a campaign, add an email sequence, and launch it.
People
Add, import, and move the people a campaign emails.
Replies
Find replies, send responses, and track message jobs.
Webhooks
Get notified when emails send, replies arrive, and more.
Start here
- Quickstart — get an API key and make your first request.
- Campaign setup — build and launch a campaign end to end.
- Lead management and Handling replies — day-two operations.
Every endpoint and object is documented in the API Reference. New keys are created in Furnace Account Settings and sent as Authorization: Bearer f_... — see Authentication.