Clerk Suite is built on other people's work. This page says whose, and under what terms. Grouped by which program uses what. Last checked 27 August 2026.
Everything in this section belongs to ChessClerk and is loaded only when ChessClerk is on. The GPL obligation below is ChessClerk's alone.
ChessClerk includes and distributes Stockfish.js 18, a WebAssembly build of the Stockfish chess engine, which runs entirely in your browser.
Licensed under the GNU General Public License, version 3.
Stockfish is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. It is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
Complete corresponding source code:
Stockfish.js 18 © 2026 Chess.com, LLC. Based on Stockfish by T. Romstad, M. Costalba, J. Kiiski, G. Linscott and other contributors. Neural networks by Linmiao Xu (linrock). The build shipped here is unmodified.
Maia-2, a neural network trained to predict human moves at a given rating rather than to find the best move.
Licensed under the MIT License. © CSSLab, University of Toronto.
Tang, Jiao, McIlroy-Young, Kleinberg, Sen and Anderson. Maia-2: A Unified Model for Human-AI Alignment in Chess. NeurIPS 2024.
Runs the Maia model in your browser. Loaded on demand from a CDN.
Licensed under the MIT License. © Microsoft Corporation.
ChessClerk queries the public Lichess API for cloud evaluations and puzzles.
Lichess is free and open-source software, licensed under the GNU Affero General Public License v3. Its game and puzzle databases are released into the public domain under CC0.
lichess.org · database.lichess.org · github.com/lichess-org/lila
Clerk Suite is not affiliated with or endorsed by Lichess.
The twelve piece images are the standard Cburnett set.
Licensed under Creative Commons Attribution-ShareAlike 3.0 Unported. Created by Cburnett, via Wikimedia Commons. Used unmodified, with no additional restrictions applied.
The attribution notice and the full text of the license are distributed with the work, as the license requires: read them here.
Hosting, authentication and storage are provided by Google Firebase. The API proxy runs on Cloudflare Workers. Payment and escrow are handled by Stripe. None of the three is redistributed here; all are services Clerk Suite uses.
The clerk is powered by models from Anthropic, Google, OpenAI, xAI, Mistral, Cohere, Together, Groq, Hugging Face, OpenRouter and Replicate, accessed over their APIs. Those models are not distributed with Clerk Suite and remain the property of their providers, under their own terms of service.
Speech in and out is handled by OpenAI. Web search is handled by Brave.
No third-party code is redistributed by any of these. They are original work running on the shared services named above.
ListClerk's background checks are run by a third-party screening provider, which is a service rather than redistributed software. Which provider is named on the privacy page, where it matters.
ArithMagic, SandBlast, HexClerk, SpringerChase, EarthQuest and Clown Car are original work. Each runs entirely in your browser with no account, no server and no third-party code.
The Clerk Suite application code is © 2026 Clerk Suite LLC. All rights reserved.
The shared library of verified chess lines is a separate thing and is not covered by that. Positions, evaluations and plans contributed to the public library carry no author, no owner, and no restriction. Reprint what you like.
If you believe a licence is misstated or an attribution is missing, tell the clerk and it will be filed.