> ## Documentation Index
> Fetch the complete documentation index at: https://www.marqeta.com/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# Original Credit Transaction (OCT) Simulations Overview

> Use these endpoints to simulate original credit transaction (OCT) authorizations, clearing, captures, and capture reversals.

Use these endpoints to simulate original credit transaction (OCT) authorizations, clearing, captures, and capture reversals.

## Available operations

| Operation | Method | Endpoint |
| :- | :- | :- |
| [**Simulate OCT authorization**](https://www.marqeta.com/docs/core-api/simulations-card-transactions/original-credit-transactions/simulate-oct-authorization.md) | POST | `/simulations/cardtransactions/original.credit.authorization` |
| [**Simulate OCT authorization clearing**](https://www.marqeta.com/docs/core-api/simulations-card-transactions/original-credit-transactions/simulate-oct-authorization-clearing.md) | POST | `/simulations/cardtransactions/original.credit.authorization.clearing` |
| [**Simulate OCT authorization and capture**](https://www.marqeta.com/docs/core-api/simulations-card-transactions/original-credit-transactions/simulate-oct-authorization-capture.md) | POST | `/simulations/cardtransactions/original.credit.auth_plus_capture` |
| [**Simulate OCT authorization and capture reversal**](https://www.marqeta.com/docs/core-api/simulations-card-transactions/original-credit-transactions/simulate-oct-authorization-capture-reversal.md) | POST | `/simulations/cardtransactions/original.credit.auth_plus_capture.reversal` |


## Related topics

- [About Credit Account Ledger Entries](https://www.marqeta.com/docs/developer-guides/about-credit-account-ledger-entries.md)
- [About Credit Account Journal Entries](https://www.marqeta.com/docs/developer-guides/about-credit-account-journal-entries.md)
- [Card Network Certifications 2021](https://www.marqeta.com/docs/developer-guides/card-network-certifications-2021.md)
- [Card Network Certifications 2023](https://www.marqeta.com/docs/developer-guides/card-network-certifications-2023.md)
- [Simulations 2.0 — Card Transactions Overview](https://www.marqeta.com/docs/core-api/simulations-card-transactions.md)