# Support
source: https://developer.mastercard.com/straight-through-processing/documentation/support/index.md

## FAQs {#faqs}

### General {#general}

No. Customers are required to maintain their records of suppliers. The STP API is a Hyperlink as the Engine of Application State (HATEOAS) RESTful API. This means the API is designed according to the same patterns and principles of the World Wide Web. All IDs are returned within the `_links` field of each JSON response payload. For further details about the response payload, refer to Body parameters reference sections in this documentation. Try to resend an identical payment request, ensuring you send the same `clientRef` value. STP will not duplicate the payment for that informed `clientRef`. Instead, it will send back the payment data for the `clientRef` that was previously sent.

### Onboarding {#onboarding}

A Sandbox key is intended just for testing purposes. In the Sandbox environment, you can make any changes you want.  
A Production key gives you access to the live Production environment. Any changes you make in the Production environment will affect customers and needs to be carefully considered. You have two options for renewing your keys: renewing your certificate or generating a new one. For in-depth information on the approaches you can take, proceed [here](https://developer.mastercard.com/platform/documentation/getting-started-with-mastercard-apis/renewing-your-keys/).
Please note that renewing your key or creating a new key will not modify your Client ID (the first 48 characters of the key used by Mastercard to authenticate you).
Therefore, you do not need Mastercard involvement during this process.

If you choose to create a new key: please consider that having more than one key for the same environment can cause service disruption.
Please remember to revoke the old key if you decide to create a new one.
One year. By renewing your key, you should be prompted again to download the P12 certificate, and then the DER and PEM certificates will be emailed to you. Please refer to the [Connect using Open API](https://developer.mastercard.com/straight-through-processing/tutorial/connect-using-open-api/index.md) tutorial. Please refer to <https://developer.mastercard.com/support>. Provide the logref value taken from the error message so we can further assist you.

### Performance {#performance}

For STP MPGS APIs, the average response time is 0.3 seconds. The average throughput is 4 hits per second.

### Policy {#policy}

The throttling is 5.22 KiB per second.

### Support {#support}

* In the event that your team experiences issues, write to "commercial.support@mastercard.com" and outline the following:

1. Email Subject: STP API: Issue with (Describe Issue Here).
2. Body: Include details about the nature of the request, along with screenshots, if possible, to help expedite the resolution.
3. Include these details:
   * Card Number
   * Card Product
   * Transaction date, time, amount
   * Merchant Name, ATM operator, or Bank Name
   * Merchant Location (country, city, address)
   * Merchant Response, Terminal Message
   * Acquirer Bank (if known)
   * Detailed explanation of issue
* [The API Status Page](https://developer.mastercard.com/api-status) informs Mastercard Developers users of the status of each API.

## Get help {#get-help}

### Contact us for technical support. {#contact-us-for-technical-support}