# Korea Filings

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An HTTP API that turns Korean corporate disclosures (DART · 전자공시)
into machine-ready English. **The filing feed is free** — browse the
market or watch a single ticker and get English company names, English
filing types, importance scores and links to the DART original, with no
wallet, no API key and no signup. **Paid calls buy the explanation**: an
AI summary of what a specific filing actually says, 0.005 USDC over Base
via [x402](https://www.x402.org/). Built for **autonomous AI agents and
indie agent builders** who need diverse data sources and prefer
pay-per-call to subscriptions.

Korean financial data is the surface we ship today, but the value
propositions that drive adoption are pay-per-call instead of monthly
contracts and standard x402 instead of bespoke auth — the same shape
would apply to any other public-records API. No API key, no signup,
no procurement loop.

**Live**: <https://koreafilings.com> · API at
<https://api.koreafilings.com> · interactive docs at
[`/swagger-ui`](https://api.koreafilings.com/swagger-ui/index.html).

## What it does

Raw DART data is free, but it's in Korean and structured for human
filings clerks, not LLMs. Korea Filings turns every disclosure into a
structured, cached, English-summarised JSON payload — agents resolve
a Korean company by name for free, then fetch a batch of summaries
for that ticker in one paid x402 call. The summary is built from the
filing body itself (not just the title), so quantitative events come
back with the actual amounts, dilution percentages, counterparty
names, and effective dates extracted from the Korean source. Two
examples — a light governance event and a quantitative capital-raise:

```json
{
  "rcptNo": "20260424900874",
  "summaryEn": "Global SM's stock trading was suspended at 09:00 KST on April 24, 2026, pending an updated electronic registration tied to a planned 1-for-2 stock consolidation. The suspension follows a board resolution dated April 21; trading resumes April 26 once the registration completes. Existing shareholders' record positions are unaffected.",
  "importanceScore": 8,
  "eventType": "TRADING_SUSPENSION",
  "sectorTags": ["Capital Goods"],
  "tickerTags": ["095440"],
  "actionableFor": ["traders"],
  "generatedAt": "2026-04-24T08:47:51Z"
}
```

A quantitative event — [Samsung Electronics dividend decision](https://dart.fss.or.kr/dsaf001/main.do?rcpNo=20260430800106), returned verbatim from a live Base mainnet paid call (settled [on-chain](https://basescan.org/tx/0x5a0403ae18db0394cb6121e6ca26aac75f44f0bb8a5d0db5dab61e84d9995a20)):

```json
{
  "rcptNo": "20260430800106",
  "summaryEn": "Samsung Electronics decided on a quarterly cash dividend of KRW 372 per common share and KRW 372 per preferred share, totaling KRW 2,453,315,636,604. The dividend yield is 0.2% for common shares and 0.3% for preferred shares. The record date is March 31, 2026, with payment scheduled for May 29, 2026.",
  "importanceScore": 7,
  "eventType": "DIVIDEND_DECISION",
  "sectorTags": ["Technology Hardware & Equipment"],
  "tickerTags": ["005930"],
  "actionableFor": ["traders", "long_term_investors"],
  "generatedAt": "2026-05-06T07:29:45.911215Z"
}
```

The cache is the moat — the first agent to request a disclosure pays
the LLM cost; every subsequent agent for the same `rcpt_no` hits a
near-zero-cost DB lookup and still pays the same flat 0.005 USDC per
summary. Batch by-ticker calls hit the same cache row-for-row, so a
five-summary call is five cache lookups against one transferred
USDC payment. Margins compound as adoption grows.

## How to use it

Pick whichever surface fits your stack. All three speak the same x402
flow under the hood; the wallet that signs the `PAYMENT-SIGNATURE` header *is*
the identity. No API keys. No signup.

### TypeScript SDK

```bash
npm install koreafilings
```

```ts
import { KoreaFilings } from 'koreafilings';

const client = new KoreaFilings({
  privateKey: process.env.PAYER_PRIVATE_KEY as `0x${string}`,
  network: 'base',
});

// 1. Free — Korean / English company name → six-digit KRX ticker
const matches = await client.findCompany('Samsung Electronics');
const ticker = matches[0]!.ticker; // "005930"

// 2. Paid — 0.005 × limit USDC, settled via x402 in one round-trip
const filings = await client.getRecentFilings(ticker, 5);
for (const f of filings) {
  console.log(`[${f.importanceScore}/10] ${f.eventType}: ${f.summaryEn}`);
}
console.log('paid:', client.lastSettlement?.transaction);
```

Sources for TypeScript / JavaScript callers — works in Node 18+, the
browser, Cloudflare Workers, and Vercel Functions. Full SDK docs in
[`sdk/typescript/README.md`](sdk/typescript/README.md).

### Python SDK

```bash
pip install koreafilings
```

```python
from koreafilings import Client

with Client(private_key="0x...", network="base") as client:
    # 1. Free name → ticker resolution
    matches = client.find_company("Samsung Electronics")
    ticker = matches[0].ticker  # "005930"

    # 2. Paid batch summary fetch (0.005 × limit USDC)
    filings = client.get_recent_filings(ticker, limit=5)
    for f in filings:
        print(f"[{f.importance_score}/10] {f.event_type}: {f.summary_en}")
    print("paid:", client.last_settlement.tx_hash)
```

### MCP server (Claude Desktop, Cursor, Continue, …)

```bash
uv tool install koreafilings-mcp
```

In your MCP client's config:

```json
{
  "mcpServers": {
    "koreafilings": {
      "command": "uv",
      "args": ["tool", "run", "koreafilings-mcp"],
      "env": {
        "KOREAFILINGS_PRIVATE_KEY": "0x...",
        "KOREAFILINGS_NETWORK": "base"
      }
    }
  }
}
```

Five tools become available — three free for discovery, two paid:

- `find_company(query)` — **free**; trigram fuzzy search of 3,961
  KRX-listed companies by Korean name, English name, or ticker.
- `list_recent_filings(limit)` — **free**; market-wide recent DART
  feed (metadata only — let the agent decide what to pay for).
- `get_pricing()` — **free**; live wallet, network, USDC contract,
  per-endpoint price.
- `get_recent_filings(ticker, limit)` — **paid 0.005 × limit USDC**;
  batch AI summaries for one ticker, with the on-chain settlement
  transaction hash.
- `get_disclosure_summary(rcpt_no)` — **paid 0.005 USDC**; single
  AI summary for a known receipt number.

The natural agent flow is `find_company` → `get_recent_filings`:
one free call to resolve a name to a ticker, one paid call to fetch
summaries for that ticker.

### curl / direct HTTP

```bash
# 1) Resolve a company name to a ticker. Free, no wallet needed.
curl 'https://api.koreafilings.com/v1/companies?q=Samsung+Electronics&limit=1'
#   HTTP/2 200
#   { "matches": [{ "ticker": "005930", "nameKr": "삼성전자",
#                   "nameEn": "SAMSUNG ELECTRONICS CO.,LTD.",
#                   "market": "KOSPI", ... }] }

# 2) Probe the paid endpoint without payment — server tells you the
#    exact USDC amount it wants for `limit=N` summaries.
curl -i 'https://api.koreafilings.com/v1/disclosures/by-ticker?ticker=005930&limit=3'
#   HTTP/2 402
#   payment-required: <base64 PaymentRequired payload, amount = 15000>
#   { "x402Version": 2, "accepts": [{ "scheme": "exact",
#       "amount": "15000", "asset": "USDC", "payTo": "0x8467…",
#       ... }], ... }

# 3) Sign an EIP-3009 TransferWithAuthorization for one of the entries
#    in `accepts`, base64-encode the signed PaymentPayload, and resend
#    with the PAYMENT-SIGNATURE header (x402 v2 transport spec).
#    See testclient/payer.py for a ~150-line reference implementation.
curl -H "PAYMENT-SIGNATURE: $SIGNED" \
     'https://api.koreafilings.com/v1/disclosures/by-ticker?ticker=005930&limit=3'
#   HTTP/2 200
#   payment-response: <base64 SettlementResponse with tx hash>
#   {
#     "ticker":     "005930",
#     "chargedFor": 3,         # what the agent paid for (`limit`)
#     "delivered":  3,         # how many summaries were actually returned
#     "count":      3,         # alias of `delivered` for older clients
#     "summaries":  [ { "rcptNo": "...", "summaryEn": "...", ... }, … ]
#   }
# `chargedFor` and `delivered` diverge when a ticker has fewer recent
# filings than `limit` or when one of those filings does not yet have
# an AI summary in cache.
```

The flat 0.005 USDC `/v1/disclosures/summary?rcptNo=…` endpoint is
still there for callers that already have a 14-digit receipt number
— same x402 flow, just `amount = 5000` and a single-summary body.

## Pricing

Per call, in USDC on Base. Free endpoints (`/v1/companies`,
`/v1/companies/{ticker}`, `/v1/disclosures/recent`) carry no payment
challenge so an agent can browse before paying. The feed also answers
conditional GETs (`ETag` / `If-None-Match` → `304`), so polling it in
a loop is cheap for both sides.

| Endpoint | Method | Price (USDC) |
|---|---|---|
| `/v1/disclosures/by-ticker?ticker=…&limit=N` | GET | 0.005 × N |
| `/v1/disclosures/summary?rcptNo=…` | GET | 0.005 |

Per-result pricing on the by-ticker endpoint is declared dynamically
in the 402 challenge — for `limit=N`, the server signs `0.005 × N`
USDC into `accepts[0].amount` so the caller sees the exact charge
before authorising the wallet. The flat-rate single-summary endpoint
stays at 0.005 USDC and is the right shape when a caller already has
a 14-digit receipt number from somewhere else.

The full machine-readable pricing descriptor (current wallet, network,
USDC contract, every paid endpoint) lives at
[`/v1/pricing`](https://api.koreafilings.com/v1/pricing); agent-driven
discovery is at
[`/.well-known/x402`](https://api.koreafilings.com/.well-known/x402).
The same paid-action surface is also exposed in Agent Web Protocol
(AWP) shape at
[`/.well-known/agent.json`](https://api.koreafilings.com/.well-known/agent.json),
and a plain-English overview for AI agents lives at
[`/llms.txt`](https://api.koreafilings.com/llms.txt).

Live on **Base mainnet** via the Coinbase CDP facilitator. Every paid
call settles a real `transferWithAuthorization` on-chain in a single
hop; the merchant wallet, network, and USDC contract address are all
self-describing through `/v1/pricing` and `/.well-known/x402` so an
agent can verify the destination before signing.

## Architecture

Three logical subsystems share one Spring Boot application:

1. **Ingestion** — schedules a 30-second poll against the DART Open
   API, deduplicates by `rcpt_no`, persists raw metadata to Postgres,
   enqueues a summarisation job.
2. **Summarisation** — consumes summarisation jobs, classifies
   complexity, routes to Gemini 2.5 Flash-Lite (with Resilience4j
   rate-limiting + circuit-breaking + retries), persists English
   summary + ticker / sector tags + audit row to `llm_audit`.
3. **Paid API** — Spring MVC controller behind an `X402PaywallInterceptor`.
   Every request: read `PAYMENT-SIGNATURE` (or the legacy `X-PAYMENT`
   alias for 0.2.x clients), verify the signature with the facilitator,
   check Redis for replay, settle on a 200 response, and attach
   `PAYMENT-RESPONSE` carrying the on-chain tx hash via a
   `ResponseBodyAdvice`. If `/settle` throws or rejects, the body is
   rewritten to the x402 v2 settle-failure shape (HTTP 402 with the
   failure SettlementResponse base64-encoded into `PAYMENT-RESPONSE`
   and an empty body) so a facilitator outage cannot leak
   paid data unpaid. The interceptor short-circuits for handler methods
   without `@X402Paywall`, so `/v1/pricing`, `/.well-known/x402`, and
   the OpenAPI document stay unauthenticated.

The 402 challenge follows the
[x402 v2 transport spec](https://github.com/coinbase/x402/blob/main/specs/transports-v2/http.md):
the `PAYMENT-REQUIRED` header carries the base64-encoded
`PaymentRequired` payload (with the [`bazaar`](https://github.com/coinbase/x402/blob/main/specs/extensions/bazaar.md)
extension declaring an input/output schema for AI-agent
discoverability), while the body keeps a v1-compatible JSON copy so
older clients keep working.

Stack: Java 21, Spring Boot 3.4, PostgreSQL 16, Redis 7, Docker
Compose, Cloudflare Tunnel, Cloudflare Workers. See
[`docs/ARCHITECTURE.md`](docs/ARCHITECTURE.md) for deeper notes.

## Repository layout

```
.
├── src/                  # Spring Boot application source
├── sdk/python/           # `koreafilings` Python SDK (PyPI)
├── sdk/typescript/       # `koreafilings` TypeScript SDK (npm)
├── mcp/                  # `koreafilings-mcp` MCP server (PyPI)
├── landing/              # Marketing landing page (Cloudflare Workers)
├── testclient/           # Reference Python x402 client (testnet payer)
├── docs/
│   ├── ARCHITECTURE.md   # System design
│   ├── PRD.md            # Product requirements
│   ├── ROADMAP.md        # Six-week launch plan
│   └── STATUS.md         # Operator handoff notes
├── Dockerfile            # Multi-stage prod build (eclipse-temurin:21)
├── docker-compose.yml    # postgres + redis + app + cloudflared
└── build.gradle.kts      # Gradle (Kotlin DSL)
```

## Local development

```bash
git clone https://github.com/OldTemple91/korea-filings-api.git
cd korea-filings-api

cp .env.example .env
# Fill in:
#   POSTGRES_PASSWORD     (any strong password)
#   DART_API_KEY          (free, register at https://opendart.fss.or.kr/)
#   GEMINI_API_KEY        (free tier, https://aistudio.google.com/apikey)
#   X402_RECIPIENT_ADDRESS (your receiving wallet — only the address)

docker compose up -d postgres redis
./gradlew bootRun
```

To exercise a real x402 payment against a local instance, copy
`testclient/.env.testclient.example` to `testclient/.env.testclient`,
fill in a wallet's private key (a fresh burner wallet funded with a
dollar or two of Base mainnet USDC is the safe pattern), and run
`python testclient/payer.py`. For local development against the public
testnet facilitator, point `X402_FACILITATOR_URL` at
`https://www.x402.org/facilitator` and use Base Sepolia parameters in
your `.env`.

## Status

Live on **Base mainnet** with verified on-chain settlement.
MVP feature set:

- DART real-time ingestion (30-second poll)
- Gemini 2.5 Flash-Lite summarisation with importance scoring + sector / ticker tagging
- x402 v2 paywall with `bazaar` extension for agent-discoverable invocation
- Discovery via `/.well-known/x402`
- OpenAPI 3 spec at [`/v3/api-docs`](https://api.koreafilings.com/v3/api-docs) + interactive Swagger UI
- Python SDK ([`koreafilings` 0.3.4](https://pypi.org/project/koreafilings/)) and MCP server ([`koreafilings-mcp` 0.3.1](https://pypi.org/project/koreafilings-mcp/)) on PyPI
- Free name → ticker resolution (`find_company`) + free recent feed (`list_recent_filings`) so agents can browse before paying
- Per-result paid batch endpoint (`/v1/disclosures/by-ticker?ticker=…&limit=N`) with 0.005 × N USDC declared dynamically in the 402
- Indexed by [x402scan](https://www.x402scan.com)
- Production deploy on a Linux VPS via Cloudflare Tunnel
- Coinbase CDP facilitator (Ed25519 JWT auth) for mainnet settlement

Roadmap items in flight:

- POST `/v1/disclosures/filter` (sector + event-type query)
- SSE `/v1/disclosures/stream` (real-time push)
- Korean-language landing page
- Slack / email alerts on settlement

See [`docs/ROADMAP.md`](docs/ROADMAP.md) for the full plan.

## Contributing

Issues and PRs are welcome — particularly:

- Ports of the Python SDK to other languages (TypeScript, Go, Rust)
- Additional analytics endpoints (price reaction, comparable filings, …)
- Integrations with non-x402 agent frameworks
- Translation of the landing page into other languages

For substantial changes, please open an issue first describing the
direction so we can sanity-check fit before you build.

## License

[MIT](LICENSE).