Configure Telephony

Configure telephony for Patter

Telephony is the leg between the user's phone and your Patter server. Patter supports two carriers with full feature parity:

Both expose the same surface in Patter (phone.serve(agent), phone.call(to)). The differences are in how you configure the carrier console.

Decision tree

1. Already have a Twilio or Telnyx account? Use that one.
2. Starting fresh in the US? → Twilio. Easier onboarding, larger phone-number inventory.
3. Starting fresh in Europe / cost-sensitive? → Telnyx.
4. Need carrier features Patter doesn't bridge yet? Check the per-carrier reference below.

Detailed setup per carrier:

Read one — not both — once the user has chosen.

Webhook URL options

Whichever carrier you use, the carrier needs a public URL to reach your Patter server. Three patterns, ranked by reliability:

webhook_url is set on the Patter constructor, not on serve(). tunnel can be set on either — passing it to serve() is the most common pattern.

Python

from getpatter import Patter, Twilio, Ngrok

# Static (production) — set webhook_url on the constructor
phone = Patter(
    carrier=Twilio(),
    phone_number="+15550001234",
    webhook_url="patter.acme.com",   # no scheme, no trailing slash
)
await phone.serve(agent)

# Cloudflare tunnel (dev) — no webhook_url; pass tunnel=True to serve()
phone = Patter(carrier=Twilio(), phone_number="+15550001234")
await phone.serve(agent, tunnel=True)

# Ngrok with reserved subdomain
phone = Patter(
    carrier=Twilio(),
    phone_number="+15550001234",
    tunnel=Ngrok(hostname="acme-patter.ngrok.io"),
)
await phone.serve(agent)

TypeScript

import { Patter, Twilio, Ngrok } from "getpatter";

// Static (production) — set webhookUrl on the constructor
const phone = new Patter({
  carrier: new Twilio(),
  phoneNumber: "+15550001234",
  webhookUrl: "patter.acme.com",
});
await phone.serve({ agent });

// Cloudflare tunnel (dev) — no webhookUrl; pass tunnel: true to serve()
const dev = new Patter({ carrier: new Twilio(), phoneNumber: "+15550001234" });
await dev.serve({ agent, tunnel: true });

// Ngrok with reserved subdomain
const prod = new Patter({
  carrier: new Twilio(),
  phoneNumber: "+15550001234",
  tunnel: new Ngrok({ hostname: "acme-patter.ngrok.io" }),
});
await prod.serve({ agent });

Outbound calls (AMD, voicemail drop)

Place an outbound call through a running server. Since 0.6.3, pass wait=True to block until the call ends and get back a CallResult — its outcome field is exactly what you route on (answered / voicemail / no_answer / busy / failed), derived from real carrier AMD + call-progress signals. machine_detection is on by default since 0.6.3 — pass False only to skip per-call AMD billing. (wait=False, the default, is fire-and-forget and returns None/void; it needs a long-running serve() to keep the call alive.)

Python

from getpatter import Patter, Twilio

# `async with` keeps the local server up for the call's lifetime.
async with Patter(carrier=Twilio(), phone_number="+15550001234") as phone:
    result = await phone.call(
        to="+14155551234",
        agent=agent,
        first_message="Hi, this is Mia from Acme.",
        machine_detection=True,                            # default since 0.6.3
        voicemail_message="Sorry we missed you. Call back at +1...",
        ring_timeout=30,                                    # default 25 s
        wait=True,                                          # → CallResult
    )

    if result.outcome == "voicemail":
        ...                               # AMD hit a machine; voicemail_message was dropped
    elif result.outcome == "answered":
        handle_live_answer(result)            # transcript, cost, duration on result
    # else: no_answer | busy | failed → retry / mark in your campaign

TypeScript

import { Patter, Twilio } from "getpatter";

// `await using` keeps the local server up for the call's lifetime.
await using phone = new Patter({ carrier: new Twilio(), phoneNumber: "+15550001234" });

const result = await phone.call({
  to: "+14155551234",
  agent,
  firstMessage: "Hi, this is Mia from Acme.",
  machineDetection: true,
  voicemailMessage: "Sorry we missed you. Call back at +1...",
  ringTimeout: 30,
  wait: true,                              // → CallResult
});

if (result.outcome === "voicemail") {
  // AMD hit a machine; voicemailMessage was dropped
} else if (result.outcome === "answered") {
  handleLiveAnswer(result);                // transcript, cost, duration on result
}
// else: no_answer | busy | failed → retry / mark in your campaign

AMD on Twilio: requires the number to have voice capability. Setting a non-empty voicemail_message implicitly enables AMD, so you can omit machine_detection=True if you've set the voicemail. Patter normalizes the Twilio parameter shape automatically since 0.6.3 — older versions required PascalCase like MachineDetection.

Recording is server-wide, not per-call: pass recording=True to phone.serve(...) to enable carrier-side recording for every call routed through that server (inbound and outbound).

Verify webhook signatures

Patter validates carrier webhook signatures by default. You don't have to write code — the validators live in getpatter.handlers.common:

• Twilio: validate_twilio_signature(headers, body, auth_token, url) — HMAC-SHA1 against the request URL + sorted body params.
• Telnyx: validate_telnyx_signature(headers, body, public_key) — Ed25519 with anti-replay check (timestamp within ±5 min).

Both return False on missing header (do not raise). Patter's default handler returns 401 on False. Don't disable signature verification.

Gotchas

• Twilio mulaw 8 kHz vs Telnyx PCM 16 kHz: Patter transcodes both — your agent code never touches raw audio. Don't try to set sample rate manually.
• Twilio Cloudflare tunnel race: occasionally first call drops because the WSS upgrade hasn't propagated through the CF edge yet. Fixed by bumping grace to 5 s in 0.5.5; still less reliable than a static URL.
• Telnyx connection ID is required (not just API key). Find it in Portal → Connections → SIP/SDK. Set TELNYX_CONNECTION_ID.
• Number formats: always E.164 (+15550001234). Patter validates before dialing; non-E.164 raises ValueError.
• Outbound trunking on Telnyx requires an Outbound Voice Profile attached to the number — Twilio handles this automatically.
• Recording stores on the carrier side (Twilio Media / Telnyx Storage), never re-uploaded by Patter. URL appears in CallMetrics.recording_url.

Common errors

Related skills

• setup-patter — install + provider API keys (do this first).
• build-voice-agent — define what the agent says once a call connects.
• inspect-calls-and-metrics — dashboard, recordings, cost.

References

• Twilio console: https://console.twilio.com
• Telnyx portal: https://portal.telnyx.com
• Patter Tunneling guide: https://docs.getpatter.com/dev-tools/tunneling
• Patter Carrier reference: https://docs.getpatter.com/python-sdk/carrier · https://docs.getpatter.com/typescript-sdk/carrier