atcoder.contest_history

stable Advanced

An AtCoder user's rated contest history.

GET /v1/atcoder/contest_history

What you get#

A list of Atcoder results in Onekey's unified shape, in data (an array). An empty array is a normal, successful answer and is charged like any other; a source that reports "nothing found" as an error returns a free 404 not_found instead.

What it costs#

Advanced · 5 credits for a fresh fetch, charged only when it succeeds.
Free when served from cache (0.2 credit for a cached response over 100 KB).
Free if the request is invalid (never charged) or the source fails or reports not found (refunded).

Parameters#

Name	Type	Required	Default	What it is	Constraints
`user`	string	yes	(required)	AtCoder user id, e.g. chokudai	max 16 chars; must match `[A-Za-z0-9_]{3,16}`; trimmed, leading @ removed

Request#

curl "https://api.onekey.dev/v1/atcoder/contest_history?user=chokudai" \
  -H "x-api-key: YOUR_API_KEY"

Try it

Add your key to run this call right here. No key? Get one free. The key stays in this tab.

Recorded response#

A real Atcoder response, recorded and returned in Onekey's shape. Fields the platform does not provide are null.

json

{
  "success": true,
  "data": [
    {
      "content": {
        "title": "AtCoder Regular Contest 061",
        "createdAt": "2016-09-11T13:40:00Z"
      },
      "entity": {
        "id": "arc061.contest.atcoder.jp"
      },
      "ext": {
        "newRating": 1255,
        "oldRating": 0,
        "place": 59,
        "performance": 2455,
        "rated": true
      }
    },
    {
      "content": {
        "title": "AtCoder Regular Contest 064",
        "createdAt": "2016-12-04T13:40:00Z"
      },
      "entity": {
        "id": "arc064.contest.atcoder.jp"
      },
      "ext": {
        "newRating": 2155,
        "oldRating": 1255,
        "place": 9,
        "performance": 3192,
        "rated": true
      }
    }
  ],
  "metadata": {
    "platform": "atcoder",
    "endpoint": "contest_history",
    "cached": false,
    "stale": false,
    "age_s": 0,
    "fetched_at": "2026-01-01T12:00:00+00:00",
    "credits_charged": 5,
    "request_id": "7f3a9c2e5b1d4c8fa2e6d0b9c4f18e37"
  },
  "error": null
}

Field mapping#

How this endpoint's source fields become Onekey's unified schema. Fields the source lacks come back as null.

Source path	Onekey field	Transform
`ContestName`	`content.title`	-
`ContestScreenName`	`entity.id`	-
`EndTime`	`content.createdAt`	`toIsoDate`
`NewRating`	`ext.newRating`	`toNumber`
`OldRating`	`ext.oldRating`	`toNumber`
`Place`	`ext.place`	`toNumber`
`Performance`	`ext.performance`	`toNumber`
`IsRated`	`ext.rated`	`toBoolean`

Caching and freshness#

Fresh for about 2 minutes. Repeat calls in that window are served from cache and are free.
Between 2 minutes and 15 minutes the cached copy is still served instantly and marked stale: true while Onekey refreshes it in the background.
If the source is down when a refresh is needed, the last copy can be served for up to 1 hour more (marked stale).
A "not found" is remembered for 1 minute and is free.
The cache is shared across all customers, which is what keeps repeat calls cheap.

What can go wrong#

Status	Code	What to do
401	`unauthorized`	Check the `x-api-key` header.
402	`insufficient_credits`	Add credits; your balance must cover the price.
404	`not_found`	Unknown endpoint path.
422	`invalid_params`	Fix the parameters using the table above. Free.
429	`rate_limited`	Wait `Retry-After` seconds, then retry.
502	`upstream_error`	The source failed. Refunded; retry with backoff.

See Errors for the full list and retry guidance.

Status: stable (verified against the live source).