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Walnut Serv — Tue, 23 Jun 2026 19:55:49 +0000

Walnut Serv

Jun 23

I built Castella — a simple Android podcast player for offline listening

#showdev #android #podcast #indie

1 min read

I built Castella — a simple Android podcast player for offline listening

Walnut Serv — Tue, 23 Jun 2026 18:51:19 +0000

I wanted a podcast app that gets out of the way: search a show, subscribe, download for offline, press play.

So I built Castella — an Android podcast player focused on daily listening.

What it does

Search podcasts and subscribe via RSS / directories
Download episodes for offline (commute, gym, flights)
Queue, favorites, and playback history
Speed control, sleep timer, chapters on supported shows
Background playback + lock-screen controls

Who it's for

Android listeners who want something simple and reliable — not another bloated media app.

Try it

Google Play: https://play.google.com/store/apps/details?id=com.wrt.castella

I'd love feedback from podcast listeners and Android devs. What would make you switch from your current player?

walnutserv@gmail.com

How to Fetch YouTube Transcripts for AI Summarization and RAG

Walnut Serv — Tue, 23 Jun 2026 17:35:26 +0000

If you're building AI apps that summarize YouTube videos, power RAG over video content, or generate subtitles, you need reliable transcript text — not browser scraping that breaks every other week.

This guide shows a simple REST approach that returns JSON with timestamps, plain text, or raw timed cues.

Why transcripts matter for AI

Summarization — feed transcript text to GPT/Claude instead of sending video
RAG — chunk timed cues into a vector database for semantic search
Accessibility — build caption tools without manual SRT editing
Content indexing — search across a channel's spoken content

Quick start with curl

curl "https://get-youtube-transcript.p.rapidapi.com/transcript?video_id=jNQXAC9IVRw&format=json" \
  -H "X-RapidAPI-Key: YOUR_KEY" \
  -H "X-RapidAPI-Host: get-youtube-transcript.p.rapidapi.com"

Replace YOUR_KEY with a key from the YouTube Transcript API on RapidAPI. The Basic plan includes 100 free requests/month.

Python example

import requests

API_URL = "https://get-youtube-transcript.p.rapidapi.com/transcript"
headers = {
    "X-RapidAPI-Key": "YOUR_KEY",
    "X-RapidAPI-Host": "get-youtube-transcript.p.rapidapi.com",
}
params = {"video_id": "jNQXAC9IVRw", "format": "json"}

data = requests.get(API_URL, headers=headers, params=params, timeout=60).json()

for cue in data["transcript"]:
    print(f"[{cue['start']:.1f}s] {cue['text']}")

Response formats

format	Use case
`json`	LLM pipelines, metadata + timestamps
`text`	Simple summarization
`raw`	Subtitle/SRT workflows

Parameters

video_id — 11-char YouTube ID or pass url with full YouTube link
languages — comma-separated codes, e.g. en,pt

Production tip

For batch jobs (indexing hundreds of videos), upgrade to the Ultra plan on RapidAPI — 100k requests/month at $9. Test in the playground first with any public video ID.

Disclosure: I built this API. Feedback welcome — especially on languages, latency, and batch endpoints.

Try it: https://rapidapi.com/wrt/api/get-youtube-transcript