Privacy at Plyread
Last updated: 14 November 2026
In short
Your chess library belongs to you. Your games and Stockfish reviews are kept on your device, not on a Plyread server.
Cloudflare handles the technical information necessary to deliver and protect the website. Plyread does not use advertising or behavioural tracking.
When you get a written review, the game and its Stockfish analysis are sent to Anthropic, the company behind Claude, to write the text. Section 5 explains what is sent and how Anthropic handles it.
Plyread is built around a simple idea: your chess games belong to you.
There are no accounts, advertisements or user-tracking systems. Your games are stored on your device, and Stockfish analyses them there. Plyread does not upload your games to a server for chess analysis.
There are a few things worth knowing about how this works, what information our hosting provider receives, and what is sent when Claude writes a review.
1. What stays on your device
Plyread stores the following information in your browser’s storage on this device:
- Chess games you import or add to your library.
- Stockfish analysis, evaluations and completed reviews.
- Your player names and game preferences.
- Your progress in Take two.
- Information used by Insights to examine your playing patterns.
- A short engine log of recent reviews. It stays on your device unless you copy it into a report yourself.
This information stays on your device, except what is sent for written reviews (section 5). Plyread does not maintain an online copy of your library, and its developer cannot remotely browse your games or retrieve them from a server.
Your games may contain personal information, such as player names, usernames, dates and other details included in PGN files. That information is stored locally alongside the games themselves.
You can use Plyread without providing your real name, email address or telephone number.
2. How Stockfish handles your games
Plyread uses Stockfish 19 through Stockfish.js.
The engine is downloaded to your device and runs in your browser. All position evaluations, move analysis and searches are performed locally.
Your games are not uploaded to any chess site or analysis service.
The engine files are downloaded when needed and may be retained by your browser for future use. You do not need to download them again unless your browser removes the saved files.
3. What happens when you visit Plyread
Plyread is delivered through Cloudflare, which provides website hosting and network services. Its address is plyread.com. Until everyone has moved, the earlier address (kibitz.shaffarullah.workers.dev) serves the same application.
When you visit the website or download its files, Cloudflare receives technical information needed to deliver and protect the service. This may include your IP address, browser information, requested files and the time of your visit.
Cloudflare may process and temporarily retain network logs for security, reliability and operational purposes. Some information may be processed outside Malaysia.
Cloudflare also asks your browser to report to it when a connection to Plyread fails. A report includes the page address, the type of error and your IP address. Successful visits are not reported.
When you get a written review, your browser also sends the request to Plyread’s own server code at Cloudflare, which passes it to Anthropic (section 5).
These technical records are separate from your chess library.
Plyread does not add its own user analytics, advertising trackers or behavioural profiling. It does not sell personal information or use your activity to target advertisements.
Fonts and other application assets are served from Plyread’s own website rather than loaded from external font services.
You can read about Cloudflare’s data practices at https://www.cloudflare.com/privacypolicy/.
4. Cookies and local storage
Plyread does not use cookies for advertising or analytics.
Cloudflare may use cookies or similar technologies where necessary for website security, including protection against automated attacks.
Plyread uses browser storage for a different purpose: to save your chess games, reviews, preferences and practice progress, and the access code for written reviews.
This storage allows Plyread to work without an account or online database.
You can remove locally stored information with Delete my library in Share & export, or through your browser settings. Clearing all website data will also remove your saved games and reviews unless you have exported a backup.
Delete my library removes your games, reviews, names, Take two progress, the engine log and the access code for written reviews. A few settings stay, such as your engine choice and how long reviews take on your device, and so does the downloaded engine. Clearing this site’s data in your browser removes those too.
5. AI-written reviews
Plyread can ask Claude, an AI model made by Anthropic, to explain a review in plain words. Stockfish’s analysis still runs on your device; Claude only writes the text, and Plyread checks it against Stockfish.
What is sent. For a game: its moves; the date, result, time control, opening and clock times from its PGN; and Stockfish’s analysis and Plyread’s scores for that game. Player names are replaced with “You” and “Opponent”, except in Study games, where the players’ names are sent. For Insights: counts and scores from your reviewed games, and up to eight example positions per finding, each with the move, the game’s date and the clock time. Your library is not uploaded, and nothing is sent for games you have not reviewed.
When it is sent. Only when you tap Ask Claude to write the review or Rewrite the text. If Claude’s first answer fails Plyread’s checks, Plyread asks once more straight away. Once you have entered an access code, Insights asks Claude to explain your findings when they change. Adding games or running a Stockfish review sends nothing.
How it travels. The request goes from your browser to Plyread’s own server code at Cloudflare, which adds Plyread’s API key and passes it to Anthropic’s API. The answer comes back the same way and is saved with the review on your device. Plyread’s server code does not store or log the request or the answer, and Cloudflare’s request logging is switched off for it.
At Anthropic. Plyread uses Anthropic’s commercial API. Anthropic says it deletes API inputs and outputs within 30 days, unless they are flagged for a check under its usage policy (kept up to 2 years) or the law requires longer, and that it does not use them to train its models. You can read its practices at https://privacy.claude.com.
Which model. Reviews are written by Claude Opus 5.5. If Anthropic’s safety checks decline a request, Anthropic may pass it to another Claude model; the review then names the model that wrote it.
Access code. While written reviews are in a private test, they need an access code. Plyread keeps it in this browser’s storage so you only type it once. Plyread’s server keeps, for each code, how many written reviews and Insights explanations it has used and when it was last used, so it can apply the test’s limits. It does not keep your name with the code, or a copy of what was written.
Your choice. Written reviews are optional; the Stockfish review is complete without them, and nothing is sent unless you ask.
6. Backups and deleting your data
Because your library is stored locally, you control its primary copy.
You can export your games and reviews using Share & export. The backup file is saved wherever you choose.
Plyread does not automatically receive a copy of that backup.
You should save backups regularly, particularly before changing browsers, replacing devices or clearing website data.
If you remove Plyread or delete its browser storage, your locally stored games and reviews may be permanently lost. Plyread cannot restore them from a server because it does not keep a server backup.
Deleting your library does not automatically delete backup files you have previously exported. You must manage those separately.
7. Security
Keeping chess analysis on your device reduces the amount of information that needs to travel over the internet.
It does not eliminate every security risk.
Someone with access to your unlocked device or browser data may be able to access your saved games. Browser extensions, malicious software or compromised devices can also create risks beyond Plyread’s control.
Protect your device with its available security features and store exported backups somewhere you trust.
Plyread relies on Cloudflare’s infrastructure to help deliver and protect the website. We will review security incidents involving systems under our control and make any notifications required by applicable law.
No website or local storage system can guarantee absolute security.
8. Your privacy rights under Malaysian law
Plyread is developed in Malaysia and takes account of the Personal Data Protection Act 2010 (Act 709), as amended by the Personal Data Protection (Amendment) Act 2024.
The PDPA regulates qualifying personal data processing in connection with commercial transactions. Whether particular obligations apply depends on the nature of the processing and the circumstances of the operator.
Where applicable, Malaysian law provides rights concerning personal information, including access, correction, withdrawal of consent and objections to certain forms of processing. The amended framework also introduces additional obligations and rights, including provisions relating to data portability and personal data breaches.
Plyread’s local-first design gives you direct control over much of your chess information without needing to submit a formal request.
You can access your games through the Library, export supported data and delete locally stored information.
For personal information processed by Plyread’s operator or its service providers, you may contact us to exercise any rights available under applicable law.
Plyread cannot provide information it does not possess, such as a copy of a library stored exclusively on your own device.
For information about Malaysian data protection law or to raise a regulatory complaint, visit the Personal Data Protection Department at https://www.pdp.gov.my/.
9. Privacy rights outside Malaysia
Plyread may also be accessed by people outside Malaysia.
Depending on where you live, who operates the service and how your information is processed, other privacy laws may apply.
These include the European Union’s General Data Protection Regulation (GDPR), the United Kingdom’s GDPR and Data Protection Act 2018, and applicable United States state privacy laws, including California’s Consumer Privacy Act as amended.
Where these laws apply, they may provide additional rights, such as requesting access to personal information, correcting inaccurate information, requesting deletion, obtaining portable copies or objecting to certain processing.
For processing subject to the GDPR or UK GDPR, website delivery and security processing may rely on legitimate interests, subject to the applicable legal requirements. Sending a game to Anthropic for a written review is done to provide the feature you use.
Plyread does not sell or share personal information for targeted advertising.
The existence and extent of your legal rights depend on the law that applies to the particular processing activity. We will respond to requests in accordance with those requirements.
10. International data transfers
Your locally stored chess library is not automatically transferred outside your device.
However, Cloudflare operates an international network. Technical information associated with website requests may be processed in other countries.
Written reviews send the information in section 5 to Anthropic, which may process it in the United States, Europe, Asia and Australia and stores it in the United States. Anthropic’s commercial terms include a data processing addendum with standard contractual clauses for international transfers.
Where applicable data protection law requires safeguards for international transfers, those requirements will need to be met before the relevant processing takes place.
11. Changes to this policy
Plyread may introduce new features or change how existing ones work.
If a change affects what personal information is collected, shared or stored, this policy will be updated to explain it.
Material changes, such as a change of AI provider or of what is sent, will be disclosed before the affected feature is used.
The date at the top of this page indicates when the policy was last revised.
12. Contact
Plyread is an independent project developed in Malaysia.
For privacy questions, concerns about personal information, or requests under applicable data protection law, contact:
Operator: Shaffarullah Abdul Rahman
Privacy contact: email address to come
We will consider requests and respond as required by applicable law.