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

# Amount, currency, or timestamp validation fails

> Fix common formatting errors for amounts, currencies, and timestamps.

## Symptom

Kyren Pay rejects a request because an amount, currency, or timestamp field is invalid.

## Likely causes

* Amounts are sent as JSON numbers instead of strings.
* Amount strings contain commas, currency symbols, or unsupported precision.
* The currency is not supported for the requested product or payment method.
* The currency code is not a three-letter code such as `USD`.
* Timestamps are sent in seconds or formatted date strings instead of Unix milliseconds.
* Date-range queries use the wrong timezone or swap start and end timestamps.

## Check this in Kyren

* Confirm supported currencies before creating checkout sessions.
* Compare the product currency with the request currency.
* Review examples in the API reference for timestamp fields.

## Check this in your server

* Send amount values as strings, such as `"9.99"`.
* Use uppercase three-letter currency codes.
* Send Unix millisecond timestamps, such as `1736932200000`.
* For date ranges, ensure `start_time` is earlier than `end_time`.

## Fix

Normalize request data before calling Kyren: convert decimal amounts to strings, validate currency codes against supported currencies, and convert dates to Unix milliseconds.

## Contact support if unresolved

Contact Kyren support with the endpoint path, response error, amount string, currency code, and timestamp values used in the request.

## Related pages

* [Get supported currencies API reference](/api-reference/config/get-supported-currencies)
* [Testing](/testing)