Case studies/Media, tools & data
Sermon archive, book and audiobook · a 70th-birthday gift

Pastor Nikolay Pletnev

2026 - now

A gift for a pastor's seventieth birthday, built in the three days before the party.

Overview

Nikolay Pletnev has preached the Gospel for forty-seven years and for about ten of them was the pastor of Slavic Full Gospel Church in Tarpon Springs, Florida. For his seventieth birthday party on 7 November 2026 he got a site of his own: everything he preached on camera, his first book and his voice. It was built in the three days before the party.

The hard part was finding him. The church channel holds 1,164 videos, mostly full services with several preachers, singing and announcements, and there was no list of which sermons were his. Each of the 1,133 videos still online was downloaded as low-bitrate audio, turned into SpeechBrain ECAPA speaker embeddings and scored minute by minute against a reference of his voice; the spans that were him became sermons, 441 of them, 205 hours from 2016 to 2026. Many were interpreted into English sentence by sentence, so a second, finer embedding pass separated his voice from the interpreter's and Whisper large-v3-turbo, running on the Mac's GPU through MLX, transcribed only him.

The site, in Russian, English and Ukrainian, gives every sermon a page that opens the video at the second he begins, with a summary, themes, quotes checked against the recording and the full transcript, each paragraph linked to its moment. Around the archive sit the views a reader of sermons wants: by year, by theme, by Bible book and chapter, series, words at the Lord's Supper, stories he told, what he said about his own life, numbers, and full-text search.

The first book collects six sermons he gave to a locked-down church in the spring of 2020 and his testimony. It is typeset for print with Paged.js, readable online in a reader with light, sepia and night themes, issued in English as a second PDF, and voiced: the audiobook is cut from his own recordings, two hours in seven chapters, not a synthetic voice. A draft of the second book, gathered by theme from the whole archive, is on the site in Russian. For search and AI assistants the site carries schema.org markup for him, the book, its chapters and every sermon video, a sitemap and a video sitemap, and llms.txt files.

What was built

Stack

Pipeline

Python
Download, embed, score, transcribe and export, each step resumable
yt-dlp
Low-bitrate audio for every video on the channel
SpeechBrain ECAPA
Speaker embeddings: 4-second windows for finding him, 2- and 1-second windows for separating him from the interpreter
Whisper large-v3-turbo on MLX
Transcription on the Mac's GPU, his voice only

AI

Claude
Summaries, themes and quote selection by reviewer agents, quotes then checked against the recording; English and Ukrainian translations

Frontend

Astro 6
Static site of about 1,950 pages in three languages
TypeScript
Shared strings and data helpers across languages

Publishing

Paged.js + Chrome
Print-ready book PDFs in Russian and English
ffmpeg
Audiobook chapters cut from the service recordings

Infrastructure & DevOps

Cloudflare Pages
Hosting for pastorpletnev.com

Search & AI visibility

schema.org JSON-LD
Person, Church, Book, Chapter, VideoObject, BreadcrumbList
Sitemaps
Pages with hreflang, and a video sitemap of 1,344 entries
llms.txt
Short index and full text of the site for AI assistants

Engineering highlights

Found, not listed: the archive is wherever his voice is across ten years of services, not a list someone remembered.

The interpreter problem solved in the signal: a finer speaker pass keeps the transcript to his words.

His own voice in the audiobook, cut from the recordings rather than synthesized.

Three days from the first download to the party, with the book printed and the site live.