# What does square.payment.completed prove?

> Prove that Square captured the card payment and the money moved. Version 1.0.0, certification Provisional.

Canonical: https://provely.sh/verify/square/square.payment.completed  
Last reviewed: 2026-09-05  
Skill version: 0.1.0  
Certification: provisional  

**Prove that Square captured the card payment and the money moved. An approved payment is an authorisation hold, not a captured payment. This level reads the payment status and the card timeline together.**

*Contract identity.*

| Fact | Value |
| --- | --- |
| Contract id | `square.payment.completed` |
| Version | `1.0.0` |
| Hash | `8614830aaeb73986` |
| Completion level | `completed` |
| Publisher | Built and signed by Provely. |
| Certification | Provisional |
| Skill | [Square 0.1.0](/verify/square) |
| Valid for provider API versions | `2026-08-19` |

## What is the intent?

Charge the card for the amount.

## What is the subject and the action?

| Member | Value |
| --- | --- |
| Subject type | `square.payment` |
| Subject identity | payment_id = `$action.result.payment.id` |
| Canonical effect | `payments.card_charge` |
| Provider operation | `POST /v2/payments` |
| Idempotency | idempotency_key, retry is safe |

## How does the evidence correlate with this operation?

| Strategy | Assurance | Keys | Required |
| --- | --- | --- | --- |
| `resource_id` | strong | payment_id from `$action.result.payment.id` | yes |
| `idempotency_key` | strong | idempotency_key from `$operation.id` | no |
| `fingerprint` | weak | reference_id from `$input.reference_id`; amount from `$input.amount` | no |

## Which evidence does the contract require?

Minimum evidence level `E2`. An independent channel is required. Minimum channels: 1.

| Channel | Level | Independence | Verifier | Description |
| --- | --- | --- | --- | --- |
| `payment_readback` | E2 | provider readback | `http` | Read the payment from the provider. The http verifier returns the parsed object, so a condition path is $observed.payment_readback.payment.status. The card state sits at $observed.payment_readback.payment.card_details.status. |
| `payment_completed_events` | E3 | provider event | `webhook` | The payment events of this payment that carry the status COMPLETED. The webhook verifier returns {events, count, latest, earliest, types, duplicates_dropped}. A condition reads $observed.payment_completed_events.count. |
| `payment_created_events` | E3 | provider event | `webhook` | The payment.created events for the reference since the operation started. The webhook verifier returns {events, count, latest, earliest, types, duplicates_dropped}. A count above one shows a second charge of the card. |

## Which conditions must all hold for VERIFIED?

| Condition | Meaning | Path | Operator | Expected | Evidence |
| --- | --- | --- | --- | --- | --- |
| `card_money_captured` | Square wrote the capture into two systems. The payment object and the card timeline must both state it, and the payment must be a card payment. | — | `all_of` | The rows below state the members. | `payment_readback` |
| `payment_status_completed` | The Payment object of Square states the captured state. | `$observed.payment_readback.payment.status` | `eq` | `COMPLETED` | `payment_readback` |
| `payment_source_is_card` | The source of funds is a card. Square populates card_details only there. | `$observed.payment_readback.payment.source_type` | `eq` | `CARD` | `payment_readback` |
| `card_captured_in_window` | The card rail captured the money after the operation started. The timeline dates the capture. | `$observed.payment_readback.payment.card_details.card_payment_timeline.captured_at` | `time_after` | `$operation.created_at` | `payment_readback` |
| `payment_amount_matches` | The amount of the payment equals the requested amount. The member holds the amount without the tip. | `$observed.payment_readback.payment.amount_money.amount` | `eq` | `$input.amount` | `payment_readback` |
| `payment_currency_matches` | The currency of the payment equals the requested currency. | `$observed.payment_readback.payment.amount_money.currency` | `eq` | `$input.currency` | `payment_readback` |
| `payment_created_in_window` | The provider created the payment after the operation started. | `$observed.payment_readback.payment.created_at` | `time_after` | `$operation.created_at` | `payment_readback` |
| `payment_completed_event` | At least one payment event of this payment carries the status COMPLETED. No event type of Square names a completion, so the filter reads the status of the payload. | `$observed.payment_completed_events.count` | `gte` | `1` | `payment_completed_events` |

## Which conditions give CONTRADICTED?

| Condition | Class | Reason | Path | Operator | Expected |
| --- | --- | --- | --- | --- | --- |
| `payment_on_wrong_reference` | wrong subject | The payment carries a different reference than the intent named. | `$observed.payment_readback.payment.reference_id` | `ne` | `$input.reference_id` |
| `payment_amount_mismatch` | wrong amount | The provider charged a different amount than the intent stated. | `$observed.payment_readback.payment.amount_money.amount` | `ne` | `$input.amount` |
| `payment_predates_operation` | pre existing state | The payment is older than the operation. It proves nothing. | `$observed.payment_readback.payment.created_at` | `time_before` | `$operation.created_at` |
| `duplicate_payment_present` | duplicate side effect | Square created more than one payment for the reference since the operation started. Do not retry. | `$observed.payment_created_events.count` | `gt` | `1` |

## Which observed states map to a verdict before completion?

| Rule | Match | Verdict | Reason |
| --- | --- | --- | --- |
| `terminal_failure` | `$observed.payment_readback.payment.status` eq `"FAILED"` | FAILED | Square reports a failed payment. The response carries an error code. |
| `canceled` | `$observed.payment_readback.payment.status` eq `"CANCELED"` | CONTRADICTED | Square voided the payment. No money moved, and no retry can change that. |
| `source_not_card` | `$observed.payment_readback.payment.source_type` ne `"CARD"` | UNVERIFIABLE | The payment is not a card payment, so Square writes no card timeline. This level cannot decide. |
| `approved_not_captured` | `$observed.payment_readback.payment.status` eq `"APPROVED"` | PENDING | Square holds an authorisation. Nobody captured the payment, so the money did not move. |
| `state_not_published` | `$observed.payment_readback.payment.status` eq `"PENDING"` | UNVERIFIABLE | Square states no meaning for this state. The runtime cannot decide. Ask a person. |

## How long does the runtime observe?

| Timing member | Value |
| --- | --- |
| Initial delay | 1000 ms |
| Poll interval | 5000 ms |
| Backoff | exponential factor 2, max 60000 ms |
| Maximum attempts | 40 |
| Timeout | 604800000 ms |
| Stale read window | 20000 ms |
| On timeout | UNVERIFIABLE (`evidence_unavailable_before_timeout`), escalated to a person |

## Where do these rules come from?

- `square.openapi#/components/schemas/Payment/properties/status`: [square.openapi](https://raw.githubusercontent.com/square/connect-api-specification/master/api.json), retrieved 2026-09-08
- `square.openapi#/components/schemas/CardPaymentDetails/properties/status`: [square.openapi](https://raw.githubusercontent.com/square/connect-api-specification/master/api.json), retrieved 2026-09-08
- `square.docs.payments#payments/complete-a-payment/p1`: [square.docs.payments](https://developer.squareup.com/reference/square/objects/Payment), retrieved 2026-09-08
- `square.docs.payments#payments/autocomplete-and-the-approved-state/p4`: [square.docs.payments](https://developer.squareup.com/reference/square/objects/Payment), retrieved 2026-09-08
- `square.openapi#/components/schemas/Payment/properties/amount_money`: [square.openapi](https://raw.githubusercontent.com/square/connect-api-specification/master/api.json), retrieved 2026-09-08
- `square.openapi#/components/schemas/Money/properties/amount`: [square.openapi](https://raw.githubusercontent.com/square/connect-api-specification/master/api.json), retrieved 2026-09-08
- `square.docs.payments#payments/amounts/p1`: [square.docs.payments](https://developer.squareup.com/reference/square/objects/Payment), retrieved 2026-09-08
- `square.openapi#/components/schemas/Money/properties/currency`: [square.openapi](https://raw.githubusercontent.com/square/connect-api-specification/master/api.json), retrieved 2026-09-08
- `square.docs.payments#payments/amounts/p2`: [square.docs.payments](https://developer.squareup.com/reference/square/objects/Payment), retrieved 2026-09-08
- `square.openapi#/components/schemas/Payment/properties/created_at`: [square.openapi](https://raw.githubusercontent.com/square/connect-api-specification/master/api.json), retrieved 2026-09-08
- `square.docs.payments#payments/identifiers/p2`: [square.docs.payments](https://developer.squareup.com/reference/square/objects/Payment), retrieved 2026-09-08
- `square.events#/events/payment.updated`: [square.events](https://developer.squareup.com/reference/square/webhooks), retrieved 2026-09-08
- `square.docs.webhooks#webhooks/the-event-types/p3`: [square.docs.webhooks](https://developer.squareup.com/docs/webhooks/overview), retrieved 2026-09-08
- `square.docs.webhooks#webhooks/the-event-types/p6`: [square.docs.webhooks](https://developer.squareup.com/docs/webhooks/overview), retrieved 2026-09-08

### Can square.payment.completed return VERIFIED from the action response alone?

No. The minimum evidence level is E2. The action response is E1. The completion conditions read `payment_readback` and `payment_completed_events`.

### What happens after the timeout?

The verdict is UNVERIFIABLE with the reason `evidence_unavailable_before_timeout`. The operation goes to a person for review.

## Read next

- [Read the Square verification page](https://provely.sh/verify/square)
- [Read the square.payment.approved contract](https://provely.sh/verify/square/square.payment.approved)
- [Read the square.refund.completed contract](https://provely.sh/verify/square/square.refund.completed)
- [Read what a completion contract contains](https://provely.sh/contracts)
- [Read what a receipt proves](https://provely.sh/docs/receipts)