CPOS Companion

Codeforces & CSES companion: capture & submit, in-browser editor, profile analytics, themes, and practice tools. Local-first.

CPOS Companion is a local-first companion for Codeforces and CSES. It connects your browser to CPOS (the VS Code extension and terminal app) and layers optional practice and on-page tooling over the judge sites. No accounts, no servers — everything runs on your machine, and every feature toggles individually from the popup. CAPTURE & SUBMIT • Open a Codeforces or CSES problem and it captures the public sample tests for CPOS on your machine • Submit from CPOS (VS Code or terminal) and it autofills the submit page in your logged-in tab, picking the newest matching compiler • Optionally syncs CSES solved/attempted status when you choose to sync ON THE PROBLEM PAGE • In-browser editor — a LeetCode-style editor: run against the samples with a per-test diff and custom stdin, then submit in place (running compiles on the local CPOS runner; editing works on its own) • Code & LaTeX styling for statements, editorials and comments • Problem tools — rating badge, tag-hider / training mode, one-click sample copy, similar problems, and a per-problem timer PRACTICE & ANALYTICS • Profile analytics — activity heatmap, streaks, solved-by-rating / index, tags, verdict and language charts (public CF API, read-only) • Profile compare (VS) — stack handles side by side with a rating-history overlay • Daily problem & streak, favorites, problemset solve-status, standings tools, and rating predictions • Contest reminders before upcoming Codeforces rounds APPEARANCE • Modernize — a sleek font, calmer spacing and cards for Codeforces & CSES • One theme palette shared across the popup, the site, and every CPOS tool REQUIRES • The CPOS VS Code extension and/or terminal app running locally for capture, run, and submit • You must be logged in to Codeforces or CSES in this browser for submissions PRIVACY • No analytics, no accounts, no cloud servers • Local communication is to 127.0.0.1 only; everything else is the public Codeforces API and the sites you already use • Full privacy policy: https://github.com/Soham109/cpos/blob/main/extensions/chrome/PRIVACY.md Open source: https://github.com/Soham109/cpos VS Code extension: https://marketplace.visualstudio.com/items?itemName=sohamaggarwal.cpos-vscode