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
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". Paste your carrier credentials:
- Plivo / Twilio: Auth ID + Token
- Vonage: API Key + API Secret + Voice Application ID + Voice Private Key (four required fields) + optional Signature Secret
- Telnyx: API Key (Connection ID is optional — Rymi auto-creates a TeXML application if you don't supply one)
Credentials are verified live against the carrier before they're saved — invalid keys are rejected on the spot rather than failing silently later. 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. Webhook routing — automatic for most carriers
Inbound calls only route into Rymi if your carrier knows where to send them. For Twilio, Plivo, Telnyx, and Vonage, Rymi configures this for you — when you import or attach a number, Rymi sets the carrier's answer/voice webhook via the carrier API and verifies it. The Numbers table shows the result per number:
- Webhook auto-configured — routing is set; the number goes Live on its first inbound call.
- Set your carrier answer URL — shown only when the carrier has no automatic setup path. All four supported carriers (Twilio, Plivo, Telnyx, Vonage) are auto-configured, so you should not normally see this. Copy the shown URL and paste it into your carrier console.
- Webhook setup failed — auto-configuration ran but the carrier rejected it (a permissions or credentials gap, or the number isn't in that account). Hover for the reason and hit Retry after fixing it.
The URL, when you need it manually, is:
https://gateway.rymi.live/inbound/<provider>Routing is by the called number, so re-attaching a number to a different agent needs no carrier change.
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
For Twilio, Plivo, Telnyx, and Vonage this is set automatically. If the Numbers table shows "Set your carrier answer URL" or "Webhook setup failed", confirm your carrier's 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.