Pricing
Per-second voice billing. Per-segment SMS. Per-verification OTP. $5 credit when you add a card — never a charge.
Hosted voice agent, AI compute included.
STT + LLM + TTS + telephony. One bill. Sub-second time-to-first-audio.
BYO carrier voice, in and out.
Plug your own Asterisk / FreeSWITCH / LiveKit / Pipecat into our SIP edge.
Buy and route US DIDs in seconds.
Search by area code, attach to a trunk or AI agent, port-out anytime.
Programmable A2P messaging.
US 10DLC and Toll-Free, pass-through carrier fees published transparently.
SMS pass-through (US 10DLC)
US A2P 10DLC requires brand and campaign registration with The Campaign Registry (TCR). We pass these through at cost — they appear as separate line items on your invoice. Toll-Free SMS is the faster path at launch (1–3 day verification); 10DLC unlocks 10–100× higher throughput once registered.
Verizon rolls per-message fees into the segment price; AT&T and T-Mobile bill per-campaign monthly. Numbers above reflect 2026 published rates and may shift — we mirror TCR's rate card without markup.
How we compare
| Feature | pstn.dev | Twilio | Telnyx | Retell AI |
|---|---|---|---|---|
| AI voice (STT + LLM + TTS + telephony) | $0.06/min | n/a · BYO | n/a · BYO | $0.07–0.31/min |
| Outbound SIP trunk | $0.05/min | $0.013/min + AI | $0.0035–0.007/min | — |
| US local number | $1.50/mo | $1.15/mo | $1.00/mo | — |
| OTP / verify | $0.05/verification | $0.05/verification | $0.05/verification | — |
| Per-second billing | Yes | Per minute | Per minute | Per second |
| Free signup credit | $5 with card | $15 trial | $2 trial | $10 trial |
Competitor numbers are public list prices as of 2026 Q2 and may not reflect negotiated volume rates. We don't do volume rates — same price for everyone.
FAQ
Because vendor reconciliation eats a day a month for any team running STT/LLM/TTS separately. We bundle Deepgram Nova-3, Groq Llama 3.3 70B, and Cartesia Sonic Turbo into one bill. If you want to swap to a premium voice or a frontier model, that's a separate $0.15/min SKU — opt-in.
Yes — phase 2. The MVP runs the default stack only. BYO will let you swap LLM (use your own Anthropic/OpenAI key), TTS, or STT. We bill voice transport + telephony at $0.05/min when you BYO the rest.
Yes. We round up to the nearest second on hangup. A 10-second call costs about a tenth of a cent. Most CPaaS competitors round up to the nearest minute.
You add a card and an initial balance. We deduct as you use. Below your auto-recharge threshold (default off), we charge your card and top up. No invoices. No 60-day net terms. Hard $0 cutoff.
Default $50/day spend cap, $1,000/month, no international without opt-in, banned premium-rate prefixes, velocity heuristic that auto-pauses on anomalies. All on by default; relaxed via support after we know you.