---
"@context": https://schema.org
"@type": TechArticle
"@id": https://www.twilio.com/docs/api/errors/13513#article
headline: "13513: Say: Invalid rate value"
url: https://www.twilio.com/docs/api/errors/13513
inLanguage: en
dateModified: 2026-03-20T20:33:25.000Z
author:
  "@type": Organization
  name: Twilio Developer Education Team
publisher:
  "@type": Organization
  name: Twilio
---

# 13513: Say: Invalid rate value

Log Type: APPLICATION

Log Level: WARNING

## Description

This warning appears when the `rate` value inside `<prosody>` is invalid. Twilio uses a default rate value of 150 when this happens. Twilio supports SSML inside `<Say>`, but SSML support can vary by provider and voice.

### Possible causes

* The `<prosody>` `rate` value is malformed or not supported by the selected voice. Twilio supports only a subset of SSML tags, and unsupported SSML can cause `<Say>` to fail.
* You are using a Basic voice. Basic voices do not support SSML, so `<prosody>` is not available.

### Possible solutions

* Change the `<prosody>` `rate` value to a supported value, such as `x-slow` or a percentage like `85%`.
* Verify that the selected voice supports SSML and test the TwiML with that exact provider and voice combination before you deploy it.
* If you are using a Basic voice, remove SSML from `<Say>` or switch to a voice that supports SSML.

#### Additional resources

* [TwiML Voice: `<Say>`](/docs/voice/twiml/say)
* [Text-to-Speech (TTS)](/docs/voice/twiml/say/text-speech)