Lucius API
Invoices

Create or update a draft invoice

Creates (or updates) a draft invoice for a contract and billing period. Generates subscription / minimum charges and attaches any unbilled usage.

POST
/v1/billing/invoices/project

Authorization

AuthorizationBearer <token>

API key as Bearer token: Authorization: Bearer luc_live_.... Create keys in the dashboard under Settings > API Keys.

In: header

Request Body

application/json

TypeScript Definitions

Use the request body type in TypeScript.

Response Body

application/json

application/json

curl -X POST "https://example.com/v1/billing/invoices/project" \  -H "Content-Type: application/json" \  -d '{    "external_contract_id": "uibt-csa",    "billing_period_start": "2026-08-01",    "billing_period_end": "2026-08-31"  }'
{  "object": "invoice",  "number": "C2C-2026-0001",  "contract": "uibt-csa",  "status": "draft",  "is_new": true,  "total": 0,  "currency": "string",  "billing_period": {    "start": "string",    "end": "string"  }}
Empty

{  "error": "Missing API key"}

Empty