Telephony decision tree
Rymi is bring-your-own-carrier (BYOC) — we don't sell or manage numbers. Connect a supported provider, register the number you already own, and attach it to a published agent. Both inbound and outbound calls work the same way.
For the API-level reference of telephony endpoints, see the Telephony API. For the BYOC integration deep-dive, see Telephony Integration.
Supported carriers
| Carrier | Audio codec | Best for |
|---|---|---|
| Twilio | 8 kHz μ-law (G.711) | The most common pick. Largest country coverage, well-documented dashboard, easy to provision numbers. |
| Plivo | 8 kHz μ-law (G.711) | Cheaper than Twilio in many regions. Good fit for high-volume outbound. |
| Telnyx | 8 kHz μ-law (G.711) | Strong for tech-forward teams. Programmable routing, competitive pricing. |
| Vonage | 16 kHz Linear PCM | Higher audio fidelity (16 kHz). Pick when call quality matters more than cost. |
The flow, in order
1. Pick a carrier and create an account with them
Rymi is bring-your-own-carrier — we don't sell or manage numbers. Open an account with Twilio, Plivo, Telnyx, or Vonage and provision the numbers you want there first. The carrier bills you separately for PSTN minutes and number rental.
2. Connect the carrier in Rymi
Go to Numbers in the dashboard and pick "Connect provider", or open Settings → Telephony. Paste your carrier credentials:
- Plivo / Twilio — Auth ID + Token
- Vonage — API Key + Secret
- Telnyx — API Key + Connection ID
Only one carrier is active per workspace at a time — connecting a new one deactivates the previous.
3. Register the number in Rymi
Add the number to Rymi in E.164 format (e.g. +15551234567). Rymi can also sync your full carrier inventory read-only — you still register each one you want to use.
4. Attach the number to a published agent
Each number binds to exactly one published agent. Inbound calls to the number route to that agent's WebSocket session. Multiple agents on one number requires a custom IVR — not available in self-serve.
5. Set the carrier webhook URL
Inbound calls only route into Rymi if your carrier knows where to send them. Point the carrier's answer URL at:
https://gateway.rymi.live/inbound/<provider>?agent_id=<your-agent-id>The exact URL is shown in Rymi after you attach the number.
6. Outbound: call the API or trigger from Studio
Outbound calls are queued via POST /v1/calls with from_number (a registered Rymi number) and the recipient. Rymi dials through your connected carrier and streams audio to the agent. See the Calls API for full payload details.
Common pitfalls
Agent not published
Inbound calls hit the gateway but route to nothing. Always publish the agent before testing real calls.
Number not attached to an agent
Even a registered number is inert until you assign it. Check the Numbers page — every number should show an agent name.
Carrier webhook URL not set
The carrier never reaches Rymi. Confirm in your carrier dashboard that the answer URL points to gateway.rymi.live/inbound/<provider>.
Switched carriers and forgot
Connecting a new provider deactivates the previous one. Old numbers stop working until they're re-registered against the new carrier.
Audio sounds muffled
Plivo / Twilio / Telnyx run at 8 kHz (PSTN standard). Vonage runs at 16 kHz. If quality matters, switch to Vonage.