Why is my speech synthesis request failing for long text?

Most speech-synthesis APIs fail on long input for one of these reasons:

1. Text length limit

   • Many services cap the number of characters per request.
   • If your text exceeds that limit, the API may return an error or silently truncate.

2. Token/context limits

   • If you’re sending the text through an LLM first, the text may exceed the model’s input limit before it even reaches TTS.

3. Payload size / request timeout

   • Large requests can exceed HTTP body limits or take too long to process, causing timeouts.

4. Unsupported formatting

   • Very long text with lots of punctuation, markup, or special characters may break parsing.

5. Rate limiting or concurrency

   • Long requests sometimes trigger retries or exceed per-request quotas.

What to do

• Split the text into smaller chunks and synthesize each chunk separately.
• Keep chunks aligned with natural boundaries:
  • paragraphs
  • sentences
  • dialogue blocks
• Concatenate the audio afterward.
• If the API supports it, use:
  • streaming synthesis
  • batch jobs
  • asynchronous endpoints

Practical rule

If you’re unsure, try:

• ~1–3 paragraphs per request
• or a few thousand characters max, depending on the provider

If you want, paste the exact error message or the API/provider you’re using, and I can tell you the likely limit and how to split the text correctly.