---
title: "Colophon — Kapell"
description: "How Kapell is made — the typefaces, the technology, and the open-data community it's built on."
canonical: "https://kapell.fm/colophon/"
---

# Colophon

How Kapell is made, and who to thank for it.

Typefaces

Three faces do all the work — two from Klim, one open.

- Founders Grotesk Titling, headings, and interface labels. [Klim Type Foundry](https://klim.co.nz/collections/founders-grotesk/)
- Financier Text Running text — descriptions, essays, the reading voice. [Klim Type Foundry](https://klim.co.nz/collections/financier/)
- JetBrains Mono Telemetry, version stamps, and diagnostic readouts. [SIL Open Font License 1.1, free and open.](https://www.jetbrains.com/lp/mono/)

Site

Built with [Astro](https://astro.build/) and rendered to static HTML. The look comes from a hand-written set of CSS design tokens. Interface icons are [Lucide](https://lucide.dev/), open source under the ISC licence. Analytics are by [Plausible](https://plausible.io/): privacy-friendly, no cookies, nothing personal collected.

Client

The Kapell app itself is native [Swift](https://www.swift.org/) using [Xcode](https://developer.apple.com/xcode/) [Visual Studio Code](https://code.visualstudio.com), and [Claude Code](https://claude.com/product/claude-code) Icons are from Apple's [SF Symbols](https://developer.apple.com/sf-symbols/) and [Lucide](https://lucide.dev/).

Infrastructure

The enrichment behind Kapell runs as [Go](https://go.dev/) services, with [PostgreSQL](https://www.postgresql.org/), [DuckDB](https://duckdb.org), and [ClickHouse](https://clickhouse.com/) holding the data, on hardware from [Hetzner](https://www.hetzner.com/) managed via [Ansible](https://www.redhat.com/en/ansible-collaborative).

Data & open-source credits

Kapell's credits, samples, and history come from the open-data community. Many volunteers who write down what streaming flattens away. Every fact points back to the project that keeps it. If you can, contribute to them or support them.

- CREDITS [MusicBrainz](https://musicbrainz.org/) The spine — personnel, credits, and sample lineage, maintained by volunteers.
- FACTS [Wikidata](https://www.wikidata.org/) Structured facts and the links between them.
- PROSE [Wikipedia](https://www.wikipedia.org/) Background prose. Text is CC BY-SA 4.0 — attribution required.
- ACOUSTIC [AcousticBrainz](https://acousticbrainz.org/) Acoustic descriptors from the open archive.
- LISTENS [ListenBrainz](https://listenbrainz.org/) Open listening history and recommendations.
- AUDIO [ReccoBeats](https://reccobeats.com/) Audio features and similarity.

Trademarks

Kapell plays through the Apple Music® app and the library you already have — it's a client, not a replacement, and the music and your subscription stay with Apple.

Apple Music and Apple are trademarks of Apple Inc., registered in the U.S. and other countries and regions. Kapell is an independent, third-party app and is not affiliated with, endorsed, or sponsored by Apple Inc.