Create a webhook endpoint in the Increase dashboard or via POST /event_subscriptions with your HTTPS URL and the event categories you need (e.g., transaction.created, ach_transfer.updated)
On each incoming webhook, verify the Increase-Webhook-Signature header: HMAC-SHA256 the raw request body with your shared secret and compare to the signature header value; reject any request that does not match
Process the event payload idempotently keyed on event.id — Increase may retry delivery on non-2xx responses; store processed event IDs to avoid duplicate processing
Implement cursor-based polling as a backstop: call GET /events with a after parameter set to the ID of the last event you processed; this catches any events your webhook endpoint missed during downtime
Run the polling backstop on a scheduled interval (e.g., every 5–15 minutes) and compare events returned by polling against your processed event log; replay any missing events
For high-volume environments, use GET /events with category filters to limit polling scope (e.g., only poll for transaction.created and ach_return.created rather than all event types)
Known gotchas
Increase webhook delivery is not guaranteed to be in order; a transaction.settled event may arrive before the corresponding transaction.created event — design your handler to handle out-of-order events and store unresolvable events for later processing
The shared secret for webhook signature verification is set at subscription creation time and cannot be retrieved after creation; store it immediately and securely in your secrets manager
Cursor-based polling using event IDs is eventually consistent — there is a small window where very recent events may not yet appear in the events list; apply a short lookback buffer (e.g., subtract 60 seconds from your last poll timestamp) to avoid missing near-real-time events
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