// the take
A Next.js tutorial project built alongside a YouTube course: it exposes a rate-limited API that computes cosine similarity between text embeddings via OpenAI, with an API key dashboard and Google auth sitting on top. It's for someone following that specific tutorial or wanting a reference implementation of API key auth in Next.js, not for someone who needs a similarity service.
The API key system (create/revoke, hashed storage, rate limiting via middleware) is a reasonable reference for building the same thing yourself. Auth is wired correctly with next-auth and Google OAuth, including route protection patterns that are easy to copy. The App Router + Pages API route split shows a real migration-era Next.js pattern, which is useful if you're straddling both during an upgrade.
No tests at all, so there's nothing to verify the rate limiter or the similarity math actually does what it claims. The README is literally course notes ("Things I forgot in the video") rather than documentation — no setup instructions beyond a bare .env.example, no API reference, no example requests. Dead since June 2023 with no CI, no versioning, and a hard dependency on OpenAI's embeddings endpoint with no fallback or error handling visible in the file list. Calling it a "Similarity API" is misleading — it's a Next.js SaaS-starter boilerplate that happens to have one similarity route bolted on.
We read the README, the directory tree and a key source file in October 2026. Nobody pays to be listed. How we judge →