# Build brief — a focused alternative to TranscriptAPI

> **Verdict:** Partly, if you narrow it · **Buildability:** 58/100 · **Category:** Dev Tools
> **Source:** https://www.canitbevibecoded.com/transcriptapi
> Independent editorial assessment from Can It Be Vibe Coded? Not affiliated with, endorsed by, or derived from TranscriptAPI. Verify current pricing and capabilities before acting.

## Context

**TranscriptAPI** — YouTube video transcripts as JSON with timestamps, search and playlist endpoints. It currently costs $5/mo.

The happy path is genuinely a one-sitting build: the open-source youtube-transcript-api library fetches a caption track in a few lines, and wrapping it in FastAPI gives you a working personal endpoint. The honest gap is reliability. YouTube rate-limits and IP-blocks caption scraping at any real volume, so the DIY version works until it suddenly does not, and there is no fix without a rotating proxy pool you must rent and operate. The paid product is not selling the parsing; it is selling the unblocked pipe, plus search and playlist endpoints on top.

This brief describes a focused, single-operator replacement for the part of TranscriptAPI that is genuinely reproducible. It is deliberately narrower than the product it replaces, and it says so in writing. Build the useful core; do not pretend to have rebuilt the rest.

## What you are building

A FastAPI endpoint that takes a YouTube URL and returns the caption track as timestamped JSON.

- Build the focused developer workflow you use repeatedly, with local configuration.
- A responsive interface with real empty, loading, success, and error states.

## Requirements

### Functional

- Python 3.11.
- A rotating proxy pool if you use it at any volume.

### Non-functional

- Accessibility: semantic markup, labelled controls, visible focus, and reduced-motion support.
- Security: server-side secrets, validated input, and no credentials in the client bundle.
- Reliability: retries with backoff on external calls, and a clear failure state when a provider is down.
- Portability: the operator can export their data and leave without losing it.

## Implementation brief

Build me a small YouTube transcript API service, a personal stand-in for TranscriptAPI.
Requirements:
- Python 3.11 stack: FastAPI, uvicorn, and the youtube-transcript-api library; no
  database, one file plus a README is fine.
- GET /transcript?video=<id-or-url>: extract the video id, fetch the caption track,
  return JSON with the full text plus timestamped segments.
- Support lang= with a sensible fallback to the first available track, and report
  which track was actually used in the response.
- Clean JSON errors: 404 when captions are disabled or missing, 502 when YouTube
  blocks the fetch; never a bare 500.
- Read an optional comma-separated PROXIES var from .env and rotate per request;
  with none set, run direct.
- GET /health returning version and uptime.
- A tiny CLI example in the README: curl the endpoint, jq out the text.
- Keep it stateless and private: no accounts, no API keys, no telemetry, no storage.
- README must be honest about the failure mode: at any real volume YouTube
  rate-limits and IP-blocks caption fetches, and this build has no defense.
- Out of scope, deliberately: the rotating proxy pool and anti-blocking
  infrastructure, channel/playlist/search endpoints, bulk throughput, and SLAs.
  That reliability layer is the thing the paid product actually sells.

## Delivery standard

- Inspect the repository first, then write a short implementation plan before writing code.
- Deliver the smallest complete end-to-end workflow first; every primary control must work against persisted data.
- Use real validation and storage; never substitute fake dashboards, decorative controls, hard-coded success states, or mock integrations.
- Include responsive layouts plus genuine empty, loading, success, validation, and failure states.
- Keep secrets server-side in environment variables, provide .env.example, and never commit credentials or user data.
- Add structured logs around every external call and return actionable errors without leaking sensitive details.
- Write unit tests for the core logic and one automated test of the main user journey.
- Finish with a README covering setup, architecture, data location, backups, tests, deployment, and known limitations.

## Acceptance criteria

- [ ] A clean install starts the app using only the README and .env.example.
- [ ] The primary journey works from first visit through saved result, reload, edit, export, and deletion where applicable.
- [ ] Invalid input, missing configuration, provider failure, and an empty database each have a usable state.
- [ ] The interface works at 390px and 1440px, is keyboard navigable, and shows visible focus on every control.
- [ ] Tests, type checking, linting, and a production build all pass with no ignored failures.
- [ ] No part of the interface implies a live integration, security guarantee, or scale capability that was not actually built and verified.

## Non-goals

Do not build these, and do not claim to have replaced them:

- Staying unblocked when YouTube rate-limits caption fetches.
- Search, channel and playlist endpoints.
- Reliability at bulk volume.
- An SLA and support when YouTube changes something.
- Reliability at the vendor's scale is an operations problem, not a prompt.
- The last 20 percent is sync, migration fidelity, speed, and edge cases.

## What you still own after launch

- Run migrations, backups, restores, and dependency updates.
- Test the critical journey after every model, API, or hosting change.
- Monitor failures and fix the edge cases a first prompt will miss.

## Risk

**Operational risk.** The code is achievable; dependable data, integrations, and ongoing operations are the real cost.

Editorial confidence in this assessment: high. No independent one-shot implementation is linked yet.

## Prior art

Working open-source software you can read, fork, or borrow from before starting:

- [youtube-transcript-api](https://github.com/jdepoix/youtube-transcript-api) — open-source Python library for the core caption fetch

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