DOJ PUBLIC API · V1

API documentation

Read public DOJ user, problem, contest, and rating data as JSON. Statements and private operational data are not exposed.

Base URLhttps://doj.kr/api/v1

Quick start

The current v1 read API does not require an API key and can be called from browsers or servers.

const response = await fetch("https://doj.kr/api/v1/users/dadas08/rating-history?limit=200");
if (!response.ok) throw new Error(`DOJ API: ${response.status}`);

const { points } = await response.json();
const chartData = points.map(({ occurredAt, newRating }) => ({
  x: new Date(occurredAt),
  y: newRating
}));

Common rules

Response format: UTF-8 JSON
CORS: Access-Control-Allow-Origin: *
Time: UTC ISO 8601 strings
Rate limit: Approximately 120 requests per minute per IP

Inspect X-RateLimit-Limit, X-RateLimit-Remaining, and X-RateLimit-Reset response headers. Limits may be approximate across multiple server instances.

Private problems and contests, protected contest problem lists, emails, Discord accounts, permissions, and submission source are never returned. Profile images use public delivery URLs; legacy Base64 images may be omitted.

Endpoint overview

Method	Path	Description
GET	`/api/v1/tags`	Algorithm tag catalog
GET	`/api/v1/users`	Search users
GET	`/api/v1/users/{handle}`	Public user profile
GET	`/api/v1/users/{handle}/contest-participations`	Finished contest participations
GET	`/api/v1/users/{handle}/rating-history`	Rating history for charts
GET	`/api/v1/problems`	Search public problems
GET	`/api/v1/problems/{displayId}`	Public problem metadata
GET	`/api/v1/contests`	Search visible contests
GET	`/api/v1/contests/{slug}`	Contest metadata

Users

User handles are case-sensitive across all user API endpoints. Search terms and handles in paths must use the same letter casing as the stored handle.

GET/api/v1/usersSearch users

Name	Type	Default	Description
`q`	`string`	`""`	Case-sensitive partial handle
`limit`	`1..100`	`20`	Results per page
`cursor`	`string`	`-`	nextCursor from the previous response

GET /api/v1/users?q=dadas&limit=20

{
  "users": [{
    "handle": "dadas08",
    "rating": 1542,
    "contestsCount": 12,
    "solvedProblemCount": 84,
    "certified": true,
    "avatarUrl": "/api/storage-assets/...",
    "countryCode": "KR",
    "organization": null
  }],
  "nextCursor": null
}

GET/api/v1/users/{handle}Public user profile

Adds bio, account creation time, and follower/following counts to the search fields. Missing or non-public accounts return 404.

GET/api/v1/users/{handle}/contest-participationsContest participations

Returns finished public and invite-only contests in descending contest-time order. Running and private contests are excluded. Supports limit and cursor.

GET/api/v1/users/{handle}/rating-historyRating chart data

Returns oldest points first. Use occurredAt for the x-axis and newRating for the y-axis. Changes from private contests preserve numeric continuity while returning contest as null.

Name	Type	Default	Description
`limit`	`1..200`	`100`	History points per page
`cursor`	`string`	`-`	nextCursor from the previous response

{
  "user": { "handle": "dadas08" },
  "points": [{
    "id": "...",
    "occurredAt": "2026-07-21T09:00:00.000Z",
    "oldRating": 1501,
    "newRating": 1542,
    "delta": 41,
    "kind": "CONTEST",
    "contest": {
      "slug": "doj-contest-1",
      "title": "DOJ Contest 1",
      "startAt": "2026-07-21T09:00:00.000Z"
    }
  }],
  "nextCursor": null
}

Problems

GET/api/v1/problemsSearch public problems

Name	Type	Default	Description
`q`	`string`	`""`	Search display ID, slug, or title
`difficultyMin`	`integer`	`-`	Minimum difficulty value
`difficultyMax`	`integer`	`-`	Maximum difficulty value
`tags`	`CSV`	`""`	Tags that must all match, up to 10
`sort`	`enum`	`display_id_asc`	One of the sort values below
`limit`	`1..100`	`20`	Results per page
`cursor`	`string`	`-`	nextCursor from the previous response

display_id_asc display_id_desc difficulty_asc difficulty_desc solves_desc published_desc

GET /api/v1/problems?tags=dp,graphs&difficultyMin=6&sort=solves_desc

{
  "problems": [{
    "displayId": 95,
    "slug": "95",
    "titles": { "ko": "문제 제목", "en": "Problem title" },
    "difficulty": 12,
    "solveCount": 37,
    "timeLimitMs": 2000,
    "pythonTimeLimitMs": 4000,
    "memoryLimitMb": 512,
    "problemType": "STANDARD",
    "tags": ["dp", "graphs"],
    "authors": ["setter"],
    "reviewers": [],
    "publishedAt": "2026-08-01T00:00:00.000Z"
  }],
  "nextCursor": null
}

GET/api/v1/problems/{displayId}Public problem metadata

Returns the same metadata for one problem. Statements, I/O descriptions, constraints, samples, editorials, and judge data are excluded.

Contests

GET/api/v1/contestsSearch contests

Name	Type	Default	Description
`q`	`string`	`""`	Search slug or title
`status`	`enum`	`all`	all, upcoming, running, or ended
`limit`	`1..100`	`20`	Results per page
`cursor`	`string`	`-`	nextCursor from the previous response

GET/api/v1/contests/{slug}Contest metadata

Returns timing, window settings, rated state, problem count, description, and rules. Private contests return 404.

Pagination

When nextCursor is not null, pass it unchanged as cursor in the next request. Do not decode or edit it, and do not reuse it after changing filters or sort order.

GET /api/v1/problems?limit=20&cursor=eyJvZmZzZXQiOjIwfQ

Errors and caching

HTTP	Error	Meaning
400	`invalid_request`	Invalid query shape or range
400	`invalid_cursor`	Invalid cursor
404	`not_found`	Missing or non-public resource
429	`rate_limit_exceeded`	Rate limit exceeded
502/503	`api_unavailable`	Temporary backend failure

{ "error": "not_found" }

Respect Cache-Control headers and avoid repeatedly requesting identical data. Breaking changes will use a new versioned path.

For the general DOJ guide, see DOJ Guide.

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