Answer phone calls with a Gemini Live voice agent on Twilio, with limits on call length, tokens and daily spend.

Tested building blocks and a small reference server for taking inbound calls with a Gemini Live voice agent on Twilio. A time limit, a token budget, a cap on calls at once and a daily spend ceiling are enforced before and during every call, priced from a table you supply.

Buy callrelay for $99

One payment of $99, plus sales tax where it applies, and every future update. Delivered as a private GitHub repository you're invited to.

What it does

Audio that doesn't click: Per-call resamplers convert Twilio's 8 kHz mu-law to 16 kHz PCM on the way in and 24 kHz on the way out, carrying filter state between chunks. Works on Python 3.10 to 3.14.
Only admitted calls reach the paid stream: Twilio webhook signatures are checked with the standard library, and the media WebSocket needs a short-lived, single-use token bound to the call. A bad token is refused before the socket is accepted.
Cost limits that fail closed: A time limit with a spoken warning before the hang-up, an optional token budget, a cap on calls at once and a daily spend ceiling. A ceiling set to something that isn't a number refuses calls instead of switching itself off.
Estimates from your own prices: Each call's cost is worked out from a price table you fill in, and the estimate says what it left out. callrelay ships no prices, so none go stale.
A Live bridge you can test: A session config with voice activity detection, barge-in and transcription, a parser for audio, transcripts, tool calls and usage, and an async bridge that keeps listening after the first turn. The core runs without google-genai.
Logs that don't leak callers: A logging filter masks emails, phone numbers, card numbers (even read out in groups) and ID numbers, and cuts long transcripts to a short prefix.
A reference server with a demo: examples/server.py handles the webhook, the media stream, barge-in, the watchdog, a spoken AI disclosure (on by default) and one example tool. --demo runs a whole simulated call with no network.

After you buy

pip install "./callrelay[server]"
python3 callrelay/examples/server.py --demo   # a simulated call, no network or accounts
callrelay check                               # what your settings resolve to, and what is missing

What you get

callrelay 1.0.0: the Python library, the callrelay command and a reference Starlette server with a runnable demo, with 317 automated tests. Python 3.10 or newer.

A commercial license. Use it and change it in your own projects and your clients' projects. Don't share or resell the source. Read the license.

Every update. New versions land in the same repository; git pull to get them.

How buying works

Enter your GitHub username. You'll see the account before you pay, so you can check it's yours.
Pay $99, plus any sales tax shown at checkout, on Stripe's checkout page.
Accept the invitation GitHub emails you. Signed in as that account, you'll also find it at github.com/dominares-tools/callrelay/invitations. Invitations expire after 7 days; you can get a new one any time.

Clone and install:

git clone https://github.com/dominares-tools/callrelay.git
pip install ./callrelay

Questions

Do I need GitHub?: Yes. Access is a read-only invitation to a private repository, sent to the GitHub account you choose.
Can I get a refund?: Yes, within 14 days, no questions asked. Access ends when the refund goes through. Refund policy.
Who takes the payment?: Stripe. Your purchase is sold through Link, Stripe's checkout service, which also works out sales tax and sends your receipt.
Something wrong?: Email josephlinares02@gmail.com. Every buyer of a tool shares its repository, so support happens by email rather than in GitHub issues.