Open-source licenses
Effective October 9, 2026
How Deep Is My Voice is built on open-source software. Thank you to these projects.
pitchy
Used for measuring the pitch of your voice (the McLeod pitch method).
License: MIT. © 2018-2021 Ian Johnson.
Bricolage Grotesque
Used for the typeface (self-hosted with the site; static cuts are used for link-preview images).
License: SIL Open Font License 1.1. © The Bricolage Grotesque Project Authors.
Next.js and React
Used for the website.
License: MIT. © Vercel, Inc.; © Meta Platforms, Inc. and affiliates.
Drizzle ORM
Used for the database layer.
License: Apache-2.0. © Drizzle Team.
The reference tones in training are synthesized in your browser; no recorded samples are used.