dxc4.com

What It Is

dxc4.com is a browser-based chess analysis tool built by Field Bureau & Werkstatt. Its core idea is straightforward: no client installation, no account registration, and no reliance on backend servers. Instead, it runs Stockfish 16 locally in the browser via WebAssembly. Users can open the website and start analyzing games immediately, and once the page has loaded, it can also be used offline.

Core Features

Its AI capabilities come from Stockfish 16, mainly for position evaluation, move recommendations, line exploration, and win-rate trend analysis. Users can click engine suggestions to play moves directly on the board. When exploring alternative variations, the original line is automatically preserved as a branch, so any variations already examined are not overwritten. The tool also supports real-time recognition of 3,546 openings and provides ECO classification.

Its approach to data organization is a highlight: the moves, branches, and current position of each analysis session are encoded in the URL, making the link itself the “database.” After sharing the link, the recipient can see the exact same analysis state. This design gives up traditional account-based cloud sync, but in return it delivers a serverless, low-dependency, and privacy-friendly experience.

Import, Integration, and Privacy

dxc4.com supports importing a full game history via a Chess.com username, with month-by-month browsing and one-click access to any game. It also supports directly pasting PGN. The source text does not mention an open API. Privacy is one of its main selling points: there is no backend, no database, and no account system; Stockfish runs locally on the user’s machine, and the official description states that no data leaves the user’s device.

Pricing, Pros, and Cons

Pricing is very simple: free, with no subscription, no paywall, and no feature tiers. Its advantages include a low barrier to entry, privacy-friendly design, easy sharing, no installation requirement, and the use of the mature Stockfish 16 engine. Its limitations are that the available information does not specify whether it has a Chinese interface, customer support, mobile compatibility, search-depth controls, multi-engine comparison, or cloud-based high-compute analysis. Since it runs locally, performance may also depend on the user’s device and browser.

Who It’s For and Access from China

It is well suited to chess players who want to quickly review Chess.com games, study PGN files, explore variations, and prioritize privacy and free access. For professional players or users who need bulk cloud-based training, team collaboration, and an advanced account system, the feature set may feel lightweight. Access conditions from mainland China are not provided, so they should be considered unknown. If access is unstable, alternatives such as Lichess Analysis Board, Chess.com Analysis, Lucas Chess, and SCID may be worth considering.