Build your own integrations on top of Handoff
Handoff Scale plan customers can now connect Handoff to any external system — sync projects, estimates, invoices, proposals, and more via a fully-documented public REST API.
API Reference: api.handoff.ai/core/docs/api
Getting started
Protocol: REST over HTTPS with JSON request/response bodies.
Generate an API Key in your Handoff account settings
Send requests to any endpoint using your preferred programming language
What you can do with the API
Project management — Create and delete projects; assign a client (match-or-create by email); update name, status, and client; read schedules and phases; create a project with an AI-generated estimate or from a document — all in one call
Estimating — Build estimates with full line items and nested sections/rooms; edit or delete any line item; read back itemized breakdowns with quantities, rates, and section roll-ups; manage payment schedules; export to PDF or CSV
Proposals — Generate from an estimate; send via email and/or SMS; require client signature on approval; approve, decline, or cancel
Invoices — Create itemized invoices from an estimate; edit title, description, and contact; void to remove from the client portal; export to PDF or receipt
Contacts — Create clients (idempotent on email); edit name, email, phone, business name, and notes; search and look up contacts
Sync & content — Read org templates (client messages, documents, terms & conditions); daily logs, documents, expenses, comments, activities, and file attachments; deletion-aware delta feeds for projects, estimates, proposals, invoices, and contacts
FAQ's
Q: I created a project with an AI estimate but didn't get one back.
A: Expected behavior. AI estimate generation is async — you receive a 202 immediately, and the finished estimate is delivered to your callbackUrl in ~1–5 minutes. Make sure you've set up a callback handler.
Q: All my dollar amounts are 100× too large.
A: Money values are in integer USD cents. $1,250.00 = 125000.
Q: How do I validate my API key?
A: Call GET /me — it confirms the key is valid and returns a display label for your UI.
Availability
The Handoff API is available on the Scale plan only. If you're interested in upgrading, reach out to your account manager or contact Handoff support.