Introduction

Zeng Book documentation

Connect Zeng Book to your stack. Sync quotations, invoices, and projects with your own systems via the REST API and signed outbound webhooks.

What is Zeng Book?

Zeng Book is a SaaS quotation, invoice, and project management platform built for Singapore construction, renovation, and interior design firms. It handles BQ-style quotations, retention, GST, progress-claim invoicing, and a client-facing portal — out of the box.

These docs are for developers and operations teams who want to extend Zeng Book — pulling data into a data warehouse, posting events into Slack, syncing invoices to accounting, or building custom dashboards on top of the REST API.

How the docs are organised

API reference — Bearer-token authentication, errors, rate limits, pagination, and a page per resource.
Interactive explorer — try real requests in the browser at /docs/api (powered by Scalar; reads from our OpenAPI spec).
Integrations — outbound webhooks, the public quotation portal, no-code automation (Zapier / Make / n8n), and roadmap items like Xero accounting sync.

Conventions

All API responses are JSON. Timestamps are ISO 8601 strings in UTC.
Monetary values are floats in the org's currency (SGD by default).
Every API response carries an X-Request-Id header. Include it when reporting issues.
Webhook event IDs (evt_*) are stable — use them for idempotency on your end.

Next steps

Quickstart

Make your first API call in 5 minutes.

Authentication

Generate a key and call /v1/me.

Webhooks

Receive signed event deliveries on your endpoint.

Integrations overview

Connect Zeng Book to Slack, Sheets, Xero, and more.