# Glossary

### Core Concepts

**Request to Pay (RTP)**\
A bank-initiated payment request created by the merchant and sent to the customer’s Bank App. The customer can accept or reject the request.

**Alias**\
Customer’s phone number in the format `373xxxxxxxx`, used to address an RTP.

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### Identifiers

* **RTP ID** — Unique identifier of an RTP request.
* **Payment ID** — Unique identifier of a completed payment.
* **Order ID** — Merchant’s internal order reference.
* **Terminal ID** — Bank-assigned terminal reference.

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### Security

**Signature**\
Cryptographic value included in callback notifications. Used to ensure integrity and authenticity of the data.

**Signature Key**\
Secret key from maibmerchants project settings. Required to verify callback signatures.

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### Environments

* **Sandbox** → `https://sandbox.maibmerchants.md`
* **Production** → `https://api.maibmerchants.md`