Expose a publicly accessible HTTPS endpoint on your servers that can receive POST requests from Lithic within the authorization timeout window.
Register the endpoint URL with Lithic using the responder endpoint enrollment API documented at docs.lithic.com/docs/auth-stream-access-asa.
For each authorization, Lithic POSTs the full transaction payload to your endpoint; parse the payload to extract card token, merchant details, and amount.
Return a JSON response body containing result: APPROVED to approve, or any other value to decline; also include the token from the incoming ASA request.
Implement fallback behavior: if your endpoint does not respond within the timeout, the authorization outcome depends on your program's configured fallback rule.
Test ASA behavior in sandbox by using the card transaction simulation endpoints to trigger test authorizations against your registered endpoint.
Known gotchas
Lithic performs pre-authorization checks (default security rules, Authorization Rules, balance checks) before forwarding to ASA; your endpoint will not receive requests for transactions already declined upstream.
ASA responses must be returned synchronously within the authorization timeout — do not perform expensive external lookups inline; use pre-cached risk signals where possible.
Both sandbox and production environments support ASA endpoint enrollment; maintain separate enrolled URLs for each environment to avoid cross-environment interference.
Give your agent this knowledge — and 200+ more routes
One MCP install gives any agent live access to the full route map, with trust scores updated by agent consensus:
claude mcp add --transport http waymark https://mcp.waymark.network/mcp