Korea Data

English | 한국어

Clean, developer-friendly REST APIs for Korean public data. Korean government open data is powerful but hard to consume — Korean-only docs, XML responses, legacy auth. This suite normalizes it into simple JSON APIs.

▶ Try it on RapidAPI — free tier, no setup. Hosted and auto-updated; same code as this repo. For AI agents, it's on the MCP Registry — uvx korea-data-mcp.

APIs

API	Status	Description
Holidays & Business Days	✅ v1	Korean public holidays (incl. substitute & temporary holidays) and business-day calculations
Real Estate Transactions	✅ v1	Normalized MOLIT real transaction prices (apartment/officetel/land, sale & rent) — nationwide (261 sigungu)
Address Toolkit	🚧 planned	Road/lot address conversion, romanization
Business Registration	🚧 planned	BRN validation & enrichment

Get started

Hosted (recommended) — a maintained instance with a free tier and no setup:

→ Subscribe on RapidAPI, grab your key, and call any endpoint. RapidAPI injects the key for you — copy a ready-made snippet from its Code Snippets panel.

	RapidAPI (hosted)	Self-host
Setup	API key in seconds	data.go.kr key + server + cron
Data refresh	automatic (we run the sync)	you manage the scheduler
Cost	free tier, then paid	free (your own infra)

Both run the exact same code (this repo). Pick RapidAPI if you'd rather not operate data pipelines; self-host if you want full control.

Self-host

uv sync
uv run uvicorn app.main:app --port 8642
curl "http://127.0.0.1:8642/v1/health"

Holidays & Business Days API

# All holidays in a year (or a month)
curl "http://127.0.0.1:8642/v1/holidays?year=2026" -H "X-API-Key: <key>"

# Is a given date a holiday / business day?
curl "http://127.0.0.1:8642/v1/holidays/check?date=2026-03-02" -H "X-API-Key: <key>"

# Add N business days (skips weekends & holidays)
curl "http://127.0.0.1:8642/v1/business-days/add?date=2026-12-31&days=1" -H "X-API-Key: <key>"

# Count business days in a range (inclusive)
curl "http://127.0.0.1:8642/v1/business-days/count?start=2026-09-21&end=2026-09-27" -H "X-API-Key: <key>"

Covers official public holidays, substitute holidays (대체공휴일), temporary holidays (임시공휴일), and election days — the cases most global holiday APIs get wrong for Korea.

Real Estate Transactions API

Normalized MOLIT (Ministry of Land) real transaction prices — apartment, officetel, and land; sale, jeonse, and monthly-rent — as clean English JSON with cursor pagination.

# Real transaction prices (apartment sales in Gangnam-gu)
curl "http://127.0.0.1:8642/v1/realestate/transactions?region=11680&property_type=apartment&trade_type=sale" -H "X-API-Key: <key>"

# Filter by date range + paginate with the returned cursor
curl "http://127.0.0.1:8642/v1/realestate/transactions?region=11680&date_from=2026-01-01&limit=50&cursor=<next_cursor>" -H "X-API-Key: <key>"

# Region codes (LAWD 5-digit)
curl "http://127.0.0.1:8642/v1/realestate/regions" -H "X-API-Key: <key>"

Daily sync ingests the current + previous month; use the backfill CLI for history:

uv run python scripts/backfill.py --from 2025-01 --to 2025-12 --regions 11680,11650

Configuration

Environment variables (prefix KDS_, .env supported):

Variable	Default	Description
KDS_DEV_MODE	false	Skip API-key auth (local dev)
KDS_API_KEYS	—	Comma-separated accepted API keys
KDS_PROXY_SECRETS	—	Comma-separated marketplace proxy secrets
KDS_DB_PATH	data/kds.db	SQLite path
KDS_DATA_GO_KR_KEY	—	data.go.kr service key (optional; enables holiday + real-estate sync)
KDS_ENABLE_SCHEDULER	true	Holiday (weekly) + real-estate (daily) sync scheduler
KDS_RE_REGIONS	all 261 nationwide sigungu	Comma LAWD codes to sync (subset override)
KDS_RE_DATASETS	all	Comma dataset keys (apt_trade, apt_rent, offi_trade, offi_rent, land_trade)

Data sources & attribution

• Holiday data: KASI Special Day Information (한국천문연구원 특일정보), via Korea Public Data Portal (data.go.kr) — KOGL Type 1. Ships with bundled seed data (2025–2027); refreshed weekly when a service key is configured.
• Real transaction data: MOLIT 실거래가 공개시스템 (국토교통부), via Korea Public Data Portal (data.go.kr) — KOGL Type 1.

Run as a daemon (macOS)

# Install & start (auto-restart on crash, start at login)
./scripts/install-daemon.sh

# With Cloudflare Tunnel (after one-time `cloudflared tunnel login/create`)
./scripts/install-daemon.sh --with-tunnel

# Logs
tail -f ~/Library/Logs/kds/api.out.log

# Uninstall
launchctl bootout "gui/$(id -u)" ~/Library/LaunchAgents/com.choiyounggi.kds-api.plist
rm ~/Library/LaunchAgents/com.choiyounggi.kds-api.plist

To keep the machine awake for serving, disable system sleep (sudo pmset -a sleep 0) or use a dedicated always-on machine. See deploy/cloudflared.example.yml for exposing the API via Cloudflare Tunnel without opening ports.

Handling concurrent traffic

The read path and the write path are separated so traffic scales independently:

• SQLite in WAL mode (set once at init) + busy_timeout — readers never block the daily writer and vice-versa, and multiple read workers can run concurrently.
• API process is read-only, multi-worker. scripts/run.sh runs uvicorn with --workers ${KDS_WORKERS:-2} and KDS_ENABLE_SCHEDULER=false. Each worker is a separate process (separate GIL); WAL lets them all read at once. Raise KDS_WORKERS to scale reads with cores.
• The daily ingest runs as its own process (com.choiyounggi.kds-sync, 04:00) via scripts/sync.py — never inside the API server, so a multi-thousand-row batch never competes with request handling for the GIL.
• Edge caching (optional): responses carry Cache-Control: no-store for security. The real-estate data is public and changes at most daily — if origin load grows, serve it with a short Cache-Control: public, max-age=... and let the CDN absorb reads.

Security checklist before exposing externally

The app is hardened at the code layer (API-key auth fail-closed, parameterized SQL, strict input validation, security headers on every response including 5xx, docs/schema off by default, sanitized errors). The following are edge/deploy responsibilities that must be in place before opening the tunnel:

• Never set KDS_DEV_MODE=true in production — it disables all auth. The app logs a warning at startup if it is on.
• Cloudflare rate limiting + WAF on the tunnel hostname — the app has no app-layer rate limit by design (edge responsibility).
• HSTS + TLS are terminated at the Cloudflare edge; confirm HSTS is enabled there (the origin serves plain HTTP on 127.0.0.1 only).
• Keep KDS_ENABLE_DOCS unset (or false) in production; set true only to serve /docs /openapi.json at the origin.

SEO marketing site (programmatic)

A static, SEO-optimized marketing site is generated from the live DB by scripts/gen_site.py. For every region that has real transaction data it emits a Korean landing page (the query users actually type — "강남구 아파트 실거래가 API" — backed by real MOLIT stats, a working curl example, and a signup CTA), plus a holidays pillar page, a home page, sitemap.xml, and robots.txt.

Quality gate (important): a region is only published if it has at least MIN_SALE_ROWS (30) apartment-sale rows. Regions without enough data are skipped — this deliberately avoids thin/doorway pages, which search engines penalize.

# generate into site/dist (reads data/kds.db)
uv run python scripts/gen_site.py --out site/dist

Config is env-driven so the same generator works for any domain (put these in deploy/site.env, gitignored — copy deploy/site.env.example):

Env	Meaning
KDS_SITE_URL	canonical/sitemap base, e.g. https://korea-data.cloud
KDS_API_ORIGIN	origin shown in the on-page curl examples, e.g. https://api.korea-data.cloud
KDS_CTA_URL	signup call-to-action (RapidAPI / Zyla / Postman listing)
KDS_SITE_DIR	output dir the app serves (default site/dist)

Serving — the API app serves it

The FastAPI app serves site/dist at all non-API paths (app.mount("/")), while /v1/* stays the JSON API. The two get different response headers: the API keeps its locked-down default-src 'none' CSP + no-store; the site gets an HTML-renderable CSP (script-src 'none', inline styles allowed) + public cache. Files are read from disk per request, so regenerating the site goes live with no app restart — only a code change needs a restart.

The site is served on the same host as the API (api.korea-data.cloud) — the API lives under /v1, the site everywhere else — so no new tunnel hostname or DNS is needed. One-time on the serving host:

cp deploy/site.env.example deploy/site.env    # KDS_SITE_URL == KDS_API_ORIGIN == https://api.korea-data.cloud
uv run python scripts/gen_site.py --out site/dist   # generate once
# restart the API app so this integration (new code) takes effect — the site is
# then live at https://api.korea-data.cloud/ , /holidays/ , /realestate/... .

Submit https://api.korea-data.cloud/sitemap.xml once in Google Search Console.

Want the site on a bare korea-data.cloud / www later? Add an ingress rule pointing that hostname at the same http://127.0.0.1:8642, route its DNS, and switch KDS_SITE_URL to it. Not required — the api host works for SEO today.

First run needs history: the daily sync only ingests the current month. To give pages real depth, backfill once — uv run python scripts/backfill.py --from 2025-07 --to 2026-06 --regions <codes> --datasets apt_trade,apt_rent.

Automate (macOS daemon)

deploy/com.choiyounggi.kds-site.plist regenerates the site daily at 04:30 (right after the 04:00 sync) via scripts/publish_site.sh. Because the app serves from disk, the refreshed pages are live immediately — no restart, no external deploy:

cp deploy/com.choiyounggi.kds-site.plist ~/Library/LaunchAgents/
launchctl bootstrap "gui/$(id -u)" ~/Library/LaunchAgents/com.choiyounggi.kds-site.plist
tail -f ~/Library/Logs/kds/site.out.log

Uptime note: since the site is served by the local app (not a CDN), its SEO availability tracks the machine — keep it awake for serving (pmset, as the API already requires). If always-on hosting is wanted later, the same site/dist can be pushed to Cloudflare Pages instead.

MCP server (AI-agent access)

The API is also packaged as a standalone Model Context Protocol server — packages/korea-data-mcp/ — so AI agents (Claude Desktop/Code, Cursor, …) can discover and call the endpoints directly. It is its own minimal package (deps: mcp, httpx) and is what gets published to PyPI / listed in the MCP Registry.

Quick add (before PyPI, straight from this repo — users bring their own key):

claude mcp add korea-data-suite --env KDS_API_KEY=<key> \
  -- uvx --from "git+https://github.com/choiyounggi/korea-data-suite#subdirectory=packages/korea-data-mcp" korea-data-mcp

See packages/korea-data-mcp/README.md for tools, client config, and uvx korea-data-mcp (once on PyPI).

License

MIT © choiyounggi