OJ API
  • atcoder
  • leetcode
  • codeforces
  • luogu
  • spoj

Problem Intelligence Infrastructure

OJ API

Every judge. One problem space.

A shared intelligence layer for developers, competitors, and AI agents to resolve, retrieve, relate, and connect algorithmic problems.

Explore the API MCP for Agents
Indexed problems
34055
Core sources
5
Version
v0.4.0
Current deployment
Token auth disabled
Mapping semantic relationships across sources
Enter the problem space

One problem space

Algorithms should not stop at platform boundaries.

OJ API normalizes fragmented judges into one coherent problem layer, preserving source identity while making every record addressable through the same mental model.

atcoder leetcode codeforces luogu spoj

Core intelligence

Four operations. One connected system.

  1. 01

    Resolve

    Turn URLs, slugs, and identifiers into concrete problem records.

    /api/v1/resolve/*
  2. 02

    Retrieve

    Read normalized problem data across every supported source.

    /api/v1/problems/*
  3. 03

    Relate

    Find conceptually adjacent problems through semantic similarity.

    /api/v1/similar
  4. 04

    Connect

    Expose the same intelligence to applications and AI agents.

    REST + MCP

Selected endpoints

Start with the paths that define the product.

GET

Problem detail

Fetch a normalized problem record by platform source and problem ID.

/api/v1/problems/{source}/{id} ↗
GET

Daily challenge

Fetch the current LeetCode daily challenge with the existing fallback behavior.

/api/v1/daily ↗
POST

Similar search

Search related problems by free-text query against the public similarity index.

/api/v1/similar ↗

Two integration surfaces

Built for software. Native to agents.

Use precise HTTP contracts in applications or expose the same capabilities as tools through Streamable HTTP MCP.

GET/api/v1/problems/leetcode/1
curl \
  -H "Authorization: Bearer <token>" \
  "http://127.0.0.1:7856/api/v1/problems/leetcode/1"
TOOLget_problem
{
  "name": "get_problem",
  "arguments": {
    "source": "leetcode",
    "id": "1"
  }
}

Authentication

One switch. Explicit access rules.

Public documentation stays open. API, status, and MCP access follow the deployment token policy.

Route Auth Disabled Auth Enabled
/PublicPublic
/healthPublicPublic
/api/v1/*PublicProtected
/statusPublicProtected
/mcpPublicProtected

Enter the system

Build against the entire problem space.

Explore the API