Build High-Volume, Low-Latency Call Transfer System (Node.js/Python + Airtable + Twilio

Posted 3 hours ago

Worldwide

Summary

I am looking for an experienced backend developer and Twilio integration specialist to build a rock-solid, high-volume outbound call bridging system. I am a non-technical founder, so I need a clean, self-hosted, and automated solution that is easy for me to manage daily. Project Overview: We need to automate a process where our system dials two separate phone numbers (Person A and Person B) simultaneously. The moment both answer, they must be instantly merged with near-zero latency. We are scaling this operation up to 15,000 transfers per day, so the architecture must be highly efficient and cost-effective. Technical Requirements & Architecture: Low-Latency Call Bridging: Do not use AI agents or speech-to-text triggers for the routing. You must use Twilio’s native infrastructure (TwiML / Conference) to handle the simultaneous dialing and instant hardware bridging of both call legs. Database Integration: The system must read phone number pairs from Airtable (or a simple database like Supabase, depending on your recommendation for handling 15k records/day without API rate limiting).Queue & Concurrency Management: Because of the volume, the script must safely handle Twilio’s Calls Per Second (CPS) limits, process records in fast batches, queue calls efficiently, and gracefully log failed/busy/no-answer attempts back into the database.Serverless Infrastructure: To avoid expensive monthly automation platforms (like Make/Zapier), the script should be deployed on a lightweight, serverless platform like AWS Lambda, Google Cloud Functions, Render, or Railway. Monthly hosting costs should be minimal.Dashboard/Trigger: Provide a simple way for me to upload my daily list of numbers to the database and trigger the script via a single button or webhook. What You Must Provide in Your Proposal: 1) A brief explanation of how you will handle the 15,000 daily API loops without hitting database rate limits. 2) Your preferred stack for this project e.g Node.js on Render + Airtable vs. Supabase 3) Examples of previous Twilio Voice or high-volume API integration projects you have built.

  • $500.00

    Fixed-price
  • Expert
    Experience Level
  • Remote Job
  • One-time project
    Project Type
Skills and Expertise
Mandatory skills
AWS Lambda
Twilio API
Node.js
Activity on this job
  • Proposals:20 to 50
  • Last viewed by client:2 hours ago
  • Interviewing:
    6
  • Invites sent:
    0
  • Unanswered invites:
    0
About the client
Member since Mar 5, 2026
  • United States
    Irvine2:02 AM
  • $1.7K total spent
    6 hires, 1 active
  • 51 hours

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