#competitive-programming

Live competitive-programming rating data from AtCoder, the largest Japanese competitive-programming platform, over its public rating-history feed — no key, nothing stored. This is the contest-rating social view for a coder: their AtCoder rating, colour tier, contest record and performance over time, distinct from the other competitive-programming and developer platforms in the catalogue — AtCoder runs its own AGC/ABC contests, its own rating system and its own community. The user endpoint returns a profile snapshot: current rating, peak rating, the AtCoder colour tier (gray, brown, green, cyan, blue, yellow, orange, red), the number of rated contests, the best placing, the best performance and the latest contest. The history endpoint returns the full per-contest rating timeline — each contest with its date, old and new rating, the rating delta, placing, performance and whether it counted as rated. The stats endpoint aggregates a coder's record: rated versus unrated contests, average and best performance, contest wins, podium finishes, the rating range and per-year activity. Build coder leaderboards, rating cards, contest-tracking bots and recruiting signals on top of real AtCoder data. Lookup is by handle; the legendary handle "tourist" is always available.

api.oanor.com/atcoder-api

Codeforces as an API — the largest competitive-programming platform, running regular rated rounds for hundreds of thousands of programmers worldwide. This API wraps the official Codeforces API into a clean, predictable JSON service. /v1/user looks up one or many competitors' profiles — current and maximum rating with the corresponding rank/title (from newbie through grandmaster to legendary grandmaster), contribution score, country, city, organization, registration date and avatar. /v1/rating returns a competitor's full rating history, contest by contest, with the old and new rating, the rating change and the rank achieved in each round — ideal for plotting a rating curve. /v1/contests lists upcoming and past contests, filterable by phase (BEFORE for the schedule of upcoming rounds, FINISHED for the archive), each with start time, duration and type. /v1/problems searches the entire Codeforces problemset by tag (dp, graphs, greedy, math, implementation, data structures and dozens more) and by difficulty-rating range, returning each problem's contest id, index, name, difficulty rating and tags with a direct link. Ratings range from ~800 to 3500+. Ideal for competitive-programming dashboards, rating trackers, training and problem-recommendation tools, and Discord/Telegram bots for CP communities. Data from the official Codeforces API, free to use. The service is resilient to Codeforces' concurrency rate-limit (automatic retry with backoff).

api.oanor.com/codeforces-api