What's free
$10 in free credits plus 20 free concurrent calls — voice-agent orchestration (STT + LLM + TTS)
Rate limits
20 free concurrent calls; voice agents ~$0.07-$0.31/min after the credit
The catch
$10 signup credit with full platform access. A voice-agent builder (orchestration), not a raw model API. Retell’s Stripe case study describes capturing a card at signup for automatic billing once the free credits are used (a third-party review claims otherwise — treat card as required).
Quickstart
First-party API — not OpenAI-compatible, so there is no drop-in base URL. The exact endpoint is in the official docs; authenticate with your API key in the Authorization: Bearer header.
curl -H "Authorization: Bearer $API_KEY" \
https://<api-base-url>/<endpoint>…or in Python:
import os, requests
r = requests.post(
"https:///",
headers={"Authorization": f"Bearer {os.environ['API_KEY']}"},
json={},
)
print(r.json()) Appears in
Change history
How this free tier has changed since we started tracking it (2026-07-31) — generated from the git history of providers.json.
- 2026-08-14 Updated the catch, card requirement
- 2026-07-31 Added to the hub