Webhooks

Tendr sends signed webhooks for checkout, refund, gas and hook events. Add endpoints in the dashboard or with POST /v1/webhooks/endpoints. Omit events to receive all of them. See Webhook signatures for verification. The body is { id, type, created, livemode, data }. data.external_ref is your order id. A retry or a resend keeps the event id (also sent as Tendr-Event-Id), so deduplicate on it. Failed deliveries are retried with exponential backoff for 3 days, and you can resend any delivery from the dashboard.

Headers

Every delivery is a POST with these headers:

Header	Value
`Tendr-Signature`	`t=<unix seconds>,v1=<hex>`: HMAC-SHA256 of `<t>.<raw body>` with the endpoint’s signing secret. For 24 hours after a secret rotation it carries a second `v1=` signed with the old secret; accept a match on any `v1`. The timestamp is the `t` in this header (there is no separate timestamp header).
`Tendr-Event-Id`	The event `id`, the same on every retry and resend.
`Content-Type`	`application/json`
`User-Agent`	`Tendr-Webhooks/1.0`

Verify the raw body before parsing it, and reject a t more than 5 minutes old. See Webhook signatures.

Checkout, payment and refund events

Event	When
`checkout.session.expired`	A session expired without a payment.
`payment.detected`	A deposit for the session was seen on chain.
`payment.processing`	The deposit is being swapped and settled.
`payment.succeeded`	The payment settled to your payout destination. Mark the order paid on this event.
`payment.refunded`	The payment was refunded (see the `refund.*` events for each return).
`payment.late`	A deposit arrived after the session ended.
`payment.held`	The payment is held for review.
`refund.pending`	A refund was created and waits to be sent.
`refund.sent`	A refund was sent on chain.
`refund.needs_address`	A refund needs a refund address before it can be sent.
`refund.cancelled`	A refund’s proposal was rejected by the signers or expired. No money moved.
`refund.failed`	A refund failed when it executed on chain. No money moved.

Gasless and hook events

Event	When
`gas.budget_low`	Sponsored gas reserved plus spent crossed 80% of the month’s budget. Once per calendar month (UTC) per mode.
`gas.budget_exhausted`	A payment was not sponsored because the month’s budget is used up. Once per month per mode.
`hook.succeeded`	Your contract accepted the `onTendrDeposit` or `on_tendr_deposit` call.
`hook.failed`	Tendr gave up calling your contract. Sent once per hook call.

gas.budget_low and gas.budget_exhausted carry mode (test or live), month (YYYY-MM), budget_usd, reserved_usd, spent_usd and remaining_usd. gas.budget_exhausted also carries requested_usd. See gas policy. hook.succeeded and hook.failed carry payment_id, session_id, external_ref, hook_call_id, chain, contract, attempts and tx_hash. hook.failed also carries error, the last error. See integrator hooks.

Payment link fields

Every checkout, payment and refund event carries data.payment_link_id and data.payer_note next to external_ref. They are always present:

Key	Value
`payment_link_id`	The id of the payment link the session was created from, or `null`.
`payer_note`	The note the payer left on the link page (plain text, up to 280 characters), or `null`.

Sessions made from a link’s public page have no external_ref (it is null): match them by payment_link_id instead. Treat payer_note as untrusted text and escape it wherever you show it.

`network_fee` on `payment.succeeded`

payment.succeeded includes data.network_fee for payments quoted with gasless payments. It is null for older payments.

{
  "paid_by": "shopper",
  "fee_mode": "token",
  "amount": "80000",
  "asset": "nep141:<1Click asset id>",
  "usd": "0.08",
  "method": "eip3009",
  "reason": "shopper_choice"
}

paid_by: merchant (you sponsored) or shopper.
fee_mode: token (the shopper paid in the payment token), native (the shopper’s wallet paid gas itself), or null when you sponsored.
amount, asset: the token fee in base units and its 1Click asset id. Null unless fee_mode is token.
usd: the quoted fee in USD, a decimal string. When Tendr collects the fee it includes Tendr’s safety margin.
method: the gasless method (eip3009, permit, paymaster, kora, meta_tx, forwarder), or null when the shopper’s wallet paid gas itself.
reason: why the shopper paid, when you were expected to sponsor. See why a payment was not sponsored.

Getting started

Concepts

Payment links

Checkout themes

API reference

Gasless payments

SDKs

Integrations

Security

Development

Headers

Checkout, payment and refund events

Gasless and hook events

Payment link fields

`network_fee` on `payment.succeeded`

​Headers

​Checkout, payment and refund events

​Gasless and hook events

​Payment link fields

​network_fee on payment.succeeded

Headers

Checkout, payment and refund events

Gasless and hook events

Payment link fields

`network_fee` on `payment.succeeded`