Overview

New to the API? Start with the API integration guide (first request, OpenAPI index, Try it, SDKs, and webhooks)—then return here for the full resource map.

You can use the API to manage resources like payment providers and configure webhooks to receive real-time event notifications.

Machine-readable paths, methods, and security are published in the OpenAPI reference (regenerated from the same Nest controllers as production).

Environments and authentication

lomi. provides separate Test and Live environments, each with its own base URL and API keys. All API requests must be authenticated using your secret API key passed in the `X-API-Key` header.

For full details on environments, base URLs, obtaining API keys, and security best practices, see the Authentication guide.

Requests and responses

All API requests should be made over HTTPS to the appropriate base URL. Request bodies (for `POST`, `PATCH` methods) should be sent as JSON.

Responses are returned in JSON format. Successful requests return `2xx` status codes. Failed requests return `4xx` or `5xx` status codes with a standardized error object in the response body.

Learn more about the structure of success and error responses in the Errors guide.

Payment behavior (beyond endpoints)

• Payment state machine — transaction/provider status transitions and completion idempotency.
• Balance and settlement — when balances update and availability delays.
• Checkout behavior — sessions, links, coupons, and checkout-wide rules.
• Payout lifecycle — withdrawal and payout completion semantics.
• Webhook reliability — retries and idempotent handling.

API resources

This core reference section covers the following API resources:

• Authentication: How to authenticate your API requests.
• Errors: Understanding API error responses.
• Data Models: Structure of key API objects.
• Merchants: Managing merchant account details and metrics.
• Customers: Creating and managing customer profiles.
• Products: Managing product definitions.
• Transactions: Retrieving payment transaction details.
• Subscriptions: Listing and retrieving subscription instances (and related SDK helpers).
• Customer Subscriptions: Managing individual customer subscriptions.
• Checkout Sessions: Creating sessions for online checkouts.
• Payment Links: Creating shareable payment pages.
• Providers: Retrieving connected payment provider information.
• Webhooks: Managing webhook endpoints for event notifications.
• Refunds: Retrieving refund details (Beta).
• Changelog: Notable API changes and updates.

Versioning

The API is versioned in documentation and client libraries (for example the OpenAPI info.version field), but there is no /v1 prefix on HTTP paths. Breaking changes are communicated through the Changelog and migration notes; we avoid shipping incompatible changes without notice.