welldun.

welldun is where I build and document practical software + AI infrastructure. The pattern across everything here is the same: multi-tenant by default, bring-your-own-keys, with security and reliability treated as features rather than afterthoughts — and AI used where it genuinely earns its place, not as decoration.

What's being built

• Entity platform (Drafting Table) — a platform where each customer defines their own entities, fields, and relationships, and the system generates the storage, validation, APIs, and analytics from those definitions. No per-customer code. Read the series →
• Offhook — an open-source, self-hostable API for AI phone calls: STT + LLM + TTS over a real phone line, bring-your-own provider keys (stored with envelope encryption). Docs at offhook.welldun.ai. Read the series →
• Email infra — a multi-tenant email-sending API: connect your own SendGrid/Resend keys, send through one reliable surface, with a Postgres work queue, circuit breaking, idempotent writes, and signed delivery webhooks.
• Workflow automation — a visual builder (React Flow) over a durable execution engine, where adding a custom block is a single file.

The writing here is the running field notebook for these — the architecture bets, the gotchas, and the things that only show up once you ship and measure.

Me

I'm Anirudh. Previously at Stripe, and a startup co-founder and CTO before this. I like building systems and taking them apart in writing — the kind of write-up I wish existed when I was figuring the thing out.

Reach me at anirudh@welldun.ai, follow along on X, or subscribe to the RSS feed.