# Credits and limits

From the Lero API docs: https://lero.studio/docs/en#limites. Everything in one file: https://lero.studio/docs/en/llms-full.txt.

### Text-to-Speech (TTS)

- 1 credit per character of the text, charged before generating and refunded if generation fails.
- Up to 500 characters per request. For longer text, split it into sentences and join the MP3s.
- Each request generates a new audio. Keep the MP3 if you will use it again.

### Speech-to-Text (STT)

- 150 credits per minute of audio (2.5 per second), billed by the second and rounded up, only when the transcription succeeds. The whole file counts, silence included.
- Up to 2 h of audio per request. A file in the body can be up to 4 MB; by `url`, up to 500 MB.
- About 30 times real time: 1 h of audio comes back in about 2 min. Use a 300 s timeout.
- Lero does not keep the audio or the transcript. Keep the response if you will use it again.

### The account

- Up to 60 requests per minute per account, across all keys and routes.
- Concurrent requests (speech and transcription): 5 on Creator and 10 on Dev. Above that, `429 simultaneas`.
- Live conversation uses 1,000 credits per minute of call, charged per second at the end; starting a call needs at least 1 minute of balance.
- The plan allowance arrives on the first use of each month (Brasília time). Unused credits roll over up to 2 times the plan quota; anything above that expires at the turn of the month.
- Extra credits, Dev only, at the plan rate: valid for 6 months.