AI / Integration Platform
Retell AI
A multi-tenant integration platform that lets Retell AI phone agents work inside the tools customers already use, with no custom code.
Visit live site ↗- Client
- Retell AI, via AB {Ark}
- Role
- Sole engineer, end to end
- Size
- ~22k lines of TypeScript
The outcome
- 8 CRM and data platforms connected, from Salesforce to Epic FHIR
- Zapier, Make.com, n8n, ChatGPT and Claude MCP connectors
- Transcripts, sentiment and outcomes synced back automatically
- Customers integrate without any custom engineering
The story
The business need
Retell AI's phone agents are most useful when they can act on a customer's own data: call a lead from the CRM, then log what happened. Every customer used a different system, and each integration meant custom engineering work.
The build
I architected and shipped the platform on my own in Node.js and TypeScript with Express, PostgreSQL and Redis, using a ports-and-adapters design so every platform plugs into the same core. It integrates Salesforce, Zoho, GoHighLevel, Notion, Airtable, Google Workspace, Slack and Epic FHIR, with a native client app for each.
Automation and AI connectors
On top of the platform I built Zapier, Make.com and n8n connectors, plus MCP connectors for ChatGPT and Claude. Customers can trigger AI phone agents from their own workflows and get transcripts, sentiment and call outcomes written back to the source system.
Delivery
I owned the whole project: API design, auth and security, caching, platform UIs, connectors, deployment and production support. Weekly meetings with Retell AI's Technical Director and Lead Backend Engineer kept API contracts, security, webhook behavior and releases aligned.
What made it hard
- 01
Many platforms, one core
Eight platforms with different auth, data models and APIs, kept maintainable through a ports-and-adapters architecture instead of eight separate codebases.
- 02
Webhooks that never double-write
Fail-closed webhook handling with HMAC signatures, and idempotent, retry-safe call writeback, so a retried event can't create duplicate records.
- 03
Multi-tenant security
OAuth2 with PKCE, JWT-based enrollment and strict tenant isolation, so each customer's credentials and data stay separate.
Have a project in mind?
I build AI agents, integrations and full-stack products end to end. Tell me what you're working on.