Enable ASA on your Lithic program and register your settlement webhook endpoint in the Lithic dashboard
When a card authorization fires, Lithic sends a synchronous ASA webhook to your endpoint with the full transaction context (merchant, amount, card token, spend_limit details)
Respond with a JSON authorization decision: status=APPROVED or DECLINED within Lithic's required response time; you can also approve a lesser amount for partial authorizations
Maintain a real-time balance ledger per card or account in your system; decrement the balance on approval and increment on reversal or decline
When the transaction clears and settles, Lithic fires a SETTLEMENT event webhook; reconcile the settled amount against the original hold and adjust your ledger accordingly
Use Lithic's spend limit controls (card-level and account-level) as a secondary enforcement layer alongside your ASA logic to provide defense-in-depth
Known gotchas
ASA responses must arrive within Lithic's timeout window; if your endpoint is slow or unreachable, Lithic uses the configured fallback behavior — set your fallback to DECLINE to prevent unauthorized spending
Lithic ASA does not guarantee exactly-once delivery of settlement webhooks; implement idempotent processing keyed on the transaction token to avoid double-crediting on retries
Test partial authorization handling explicitly — some point-of-sale terminals do not support partial approvals and will decline the transaction regardless of your approved amount
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