official API

Not a scrape. Codeforces publishes REST. aiohttp, status=="OK" or error. No API key. Be polite. The 2s sleep before contest-participation user.status is the politeness. Redis HIT skips it.

Playground: playground. Sample tourist.

GET https://codeforces.com/api/user.info?handles={h1;h2}
GET https://codeforces.com/api/user.rating?handle=
GET https://codeforces.com/api/user.status?handle=
GET https://codeforces.com/api/contest.list?gym=

userids on /multi/{userids} is semicolon-separated (tourist;Petr). Commas are accepted and rewritten.

Heatmap years run from registrationTimeSeconds to today. days is the old window query. Prefer view. Intensity uses round, not ceil like LeetCode.

Mapper: firstName + lastName or handle → displayName. titlePhoto else avatar. organization → institution. Contests: rating / maxRating / rank from user.info, history from user.rating. badgesCount=0.

Missing user is HTTP 404 with detail, not a fake zeroed stats object. That is the luxury of an official API.

/contests/upcoming?gym=true includes gym contests. CodeTrace’s Codeforces deep dive still uses this.

No API key. Be polite.

sequenceDiagram
  participant B as Browser
  participant API as codeforces-stats
  participant CF as codeforces.com/api

  B->>API: GET /tourist/stats
  API->>CF: GET user.info?handles=tourist
  API->>CF: GET user.status?handle=tourist
  Note over API: distinct contestId index verdict OK, tags as topics
  API-->>B: envelope platform codeforces

Heatmap, stats, and topics all re-fetch user.status. That list is the expensive call. get_contests_participated_by_user sleeps 2s first. Redis HIT on the HTTP envelope skips both the sleep and the second fetch.

Missing user: HTTP 404 with detail. status != "OK" from Codeforces becomes that miss.