Developer Docs

EsperWorks API

A REST API for integrating EsperWorks invoicing, contracts, and payments into your own applications. All responses are JSON. All requests must be authenticated with an API key.

Base URL: https://api.tryesperworks.com/api/v1

Quickstart

Generate an API key from Dashboard → Developer API, then make your first request:

curl https://api.tryesperworks.com/api/v1/ping \
  -H "Authorization: Bearer ew_live_xxxxxxxxxxxxxxxxxxxx"

A successful response returns your business name, key name, environment, and active scopes.

Resources

Quickstart

First API call in under 2 minutes.

Clients

Create and manage client records.

Invoices

Create, send, and track invoices.

Contracts

Read contracts and their status.

Payments

List and simulate payments.

Expenses

Log and retrieve expenses.

Webhooks

Receive real-time event notifications.

SDK & Libraries

Official client libraries.

Key concepts

Scoped keys, each API key grants access only to the modules you select (e.g. invoices:read, contracts:read). See Authentication.
Business-scoped data, all data returned is scoped to the business that owns the API key. You cannot access another business's data.
Pagination, list endpoints return paginated results. Pass ?page=2&per_page=20 to navigate.
Rate limits, 120 requests per minute per API key. See Errors & Rate Limits.