// the take
Extrapolate is Steven Tey's demo app that ages your face through time using a Replicate-hosted model, built on Next.js App Router with Cloudflare R2/Workers for photo storage and Upstash for state. It's aimed at developers who want a reference implementation for wiring third-party AI inference into a full-stack Next.js app, not at anyone who actually needs face-aging in production.
The Cloudflare Worker + R2 upload pattern in the README is a genuinely useful, copy-pasteable reference for pre-signed-style object storage without AWS. The webhook handling (Replicate completion, Stripe, Supabase customer sync) is real production glue code, not toy examples, and shows how to wire async inference callbacks into a Next.js app with server actions (app/actions/uploadAgePredict.ts).
The README is stale ("NEW README COMING SOON" has clearly been sitting there a while) and only documents REPLICATE_API_TOKEN/CLOUDFLARE/UPSTASH/POSTMARK env vars, but the actual codebase has grown Supabase auth, Stripe billing, and public photo-sharing pages (app/p/[id]) that aren't mentioned anywhere — anyone trying to self-host will hit undocumented required services. The sample Cloudflare Worker authorizes every GET request unconditionally, meaning anyone who guesses or leaks an object key can read it with no per-user scoping. No commits since December 2024, so this is a frozen snapshot rather than something actively maintained, and the core value is a thin wrapper around one Replicate model call rather than anything novel engineering-wise.
We read the README, the directory tree and a key source file in October 2026. Nobody pays to be listed. How we judge →