End-to-End Phone Integration with OpenAI, Twilio, and ElevenLabs

I’m looking for a developer who can deliver a working phone integration with OpenAI and ElevenLabs—not a demo, not instructions, but a reliable end-to-end setup. The job is to connect a phone number so that when it rings, audio is passed to ChatGPT, responses are generated, voiced through a custom voice at ElevenLabs, and streamed back to the caller in real time.

ElevenLabs and Twilio are already integrated. Already have a Twilio number. Just need to bring in an already-established ChatGPT account (no scripts, voice is already developed.)

I’ve been clear from the start that I want a true integration, not a voice clone, copy, or workaround. If you’ve worked with Twilio (or similar telephony APIs) and have actual experience shipping voice-to-ChatGPT projects, examples are more than welcome. Please read the full spec below—deliverables, milestones, and ownership details are all there.

I’m fair, but I’ve already dealt with one provider who promised far more than delivered. If you’re the kind of professional who builds what's promised, then you are welcome to be my dev :)

Wire a Phone Number to ChatGPT + ElevenLabs Voice (End-to-End Integration)

I need a working line, not a demo. Deliverables are:

Provision one virtual phone number (Twilio, number already secured).

Build a serverless handler (AWS Lambda, GCP Cloud Functions, or Cloudflare Workers).

Ingest live call audio, proxy it to previously established ChatGPT endpoint, synthesize replies with ElevenLabs voice (custom, also already established and hooked into Twilio), stream back to the caller in near real time.

Simple config panel or .env file for keys (no hard-coded secrets).

Logging limited to request IDs, timestamps, costs, and errors (no content logging).

Deliverables:

Infra-as-code or one-click deployment docs.

Source code repo with clear ownership.

Test phone number live and working.

Documentation with rollback steps.

Success test:

I call the number, hear the custom ElevenLabs voice make its own response, and get <1s response time from specific, established ChatGPT account

Calls handle interruptions gracefully.

Call doesn’t crash on silence or long pauses.

Security:

Keys stored in a managed secret store (AWS/GCP/Cloudflare).

Key handoff via temporary secure link.

No developer retention of keys.

Ownership:

I own the accounts, keys, and final code.

Dev provides clean handoff, nothing proprietary.

Milestones:

Design doc & diagram with chosen tech (10%).

“Hello world” call loop—tone in, tone out (20%).

ChatGPT stitched in (25%).

ElevenLabs stitched in (25%).

Final polish, docs, and handoff (20%).

Payment:
Milestone-based via escrow. If a milestone isn’t met, I stop and keep the code so far.

Nice-to-haves:

Whisper/Realtime API for transcription.

Wake word.

Voicemail fallback.

Spam throttling.

If at all possible... some coding magic that can allow zero turn communication at times of the agent's choosing (so agent can communicate reminders, time alerts, status updates etc-- ChatGPT has done this, documented, so it's possible)

Timeline:
1–2 weeks realistic.

Budget:
Market rate. Proposals must include examples of past Twilio/telephony work.