...

Setting up CoreCall

Connect a Twilio or Telnyx account, understand what CoreCall provisions on your behalf, place a first call, and know the limits before you hit them.

Setting up CoreCall

CoreCall needs credentials for at least one provider. Either Twilio or Telnyx alone is enough; connecting both lets you choose per call which number to use.

Connecting Twilio

You need your Account SID and either your Auth Token or an existing API Key SID and Secret. Both are in the Twilio Console.

When you connect, CoreCall does three things inside your Twilio account:

  1. Validates the Account SID.
  2. Creates a dedicated API Key for the app, so your Auth Token is not the long-lived credential sitting on your device.
  3. Deploys a small Twilio Serverless Function that returns the TwiML instructing Twilio to dial your destination.

That function is what makes outbound calling work. It lives in your account, under your billing, and you can inspect or delete it from the Twilio Console at any time.

Voice access tokens are then minted on the device, signed locally. No request to us, and no request to a server of ours, is involved in placing a call.

Connecting Telnyx

You need a Telnyx API key. CoreCall creates, idempotently:

  1. An outbound voice profile
  2. A credential connection
  3. A telephony credential

and then mints a short-lived JWT per call for the WebRTC client. Re-connecting does not create duplicates.

On macOS, Telnyx is the only voice path. See Installation for why.

Adding or removing a provider later

You are not locked into the choice you made during onboarding.

Adding the second one. Settings shows an "Add Twilio account" or "Add Telnyx account" row for whichever provider you have not configured. Connecting it runs the same provisioning steps described above, and afterwards the dialer and the SMS composer let you pick which provider each call or message goes through.

Removing one. If the other provider is still connected, the app keeps working — you simply lose the numbers and history belonging to the one you removed.

Removing the last one signs you out and returns you to onboarding. That is deliberate rather than a failure: CoreCall has no account of its own and no service to fall back on, so with no provider credentials there is nothing it can do. Your call and message history lives in your provider account, not here, so signing out does not destroy it — reconnecting the same account brings it back.

Choosing a caller ID

After connecting, CoreCall lists the numbers available on your account. Pick one as the caller ID. On Mac, Twilio numbers are hidden from the voice picker because they cannot be used for calling there.

Placing a call

Enter a destination in E.164 format — country code, no spaces, no dashes: +14155550123, not (415) 555-0123.

On iOS and macOS the call is handled through CallKit, so it appears in the system call UI and behaves like a normal call, including audio routing and the Recents list. On Android an ongoing-call notification keeps the call alive in the background.

CoreCall does not receive calls. It does not register for push notifications and will not ring when someone calls your number back. Inbound handling stays in your provider's configuration, exactly as it was before you installed the app.

Sending SMS

Messages are sent from the same numbers, through your provider's messaging API. Message history is shown per number.

One asymmetry to be aware of: Telnyx message history is best-effort. Telnyx has no inexpensive endpoint to list all messages, so CoreCall shows full history for Twilio numbers and appends Telnyx messages it sent itself. Older Telnyx messages sent from elsewhere will not appear.

Optional: AI call modes

If you configure an AI server URL and access key in settings, the dialer gains two extra modes beyond off:

  • Subtitle — live translated captions of the call, shown as it happens.
  • Interpreter — a server-side interpreter bridged into both legs of the call, so each side hears the other in their own language.

These require:

  • A Twilio caller ID. The modes are built on Twilio media streams and are hidden when a Telnyx number is selected.
  • A destination in E.164 format for interpreter mode. A non-numeric handle fails with a clear error rather than silently falling back.
  • A platform other than Mac, where they are unavailable.

You supply your own OpenAI key (and optionally a Deepgram key for word-level captions) to the server; it holds them, so the keys are never embedded in the app.

These modes are genuinely optional. CoreCall's core purpose — calling and messaging through your own provider account — works with no AI server configured at all, and that is the configuration most people should start with.

Demo Mode

Demo Mode plays a scripted call with no network access and no real audio. It exists so you can see the interface without connecting an account. Nothing in Demo Mode touches a provider or costs money.

Limits worth knowing before you hit them

  • No inbound calls.
  • Twilio voice and all AI modes are unavailable on macOS. Telnyx voice and Twilio SMS both work there.
  • AI modes are Twilio-only, on every platform.
  • Telnyx SMS history is incomplete by design.
  • Billing is yours. Every call and message is billed by your provider at your rates. CoreCall adds nothing and sees nothing.

Troubleshooting

"Twilio voice calls aren't available on Mac." Working as intended. Select a Telnyx caller ID, or use the Android build.

A call fails immediately after connecting Twilio. The serverless function may not have finished deploying. Wait a few seconds and retry; if it persists, check the Functions section of your Twilio Console to confirm it exists.

The AI mode selector is missing. Either no AI server is configured, or the selected caller ID is a Telnyx number, or you are on Mac.

Nothing dials and the number looks fine. Check it is E.164. A leading + and country code are required.

Installation