Multilingual knowledge search over 2,400 curated chunks

Full-text search over 2,438 curated knowledge chunks in 9 languages (vi, en, zh, th, id, ms, hi, ru, fr) covering Vietnam agriculture/enzyme guides and trade intelligence. $0.01/call via x402.

$0.01 USDC / call free trial: 5/day per IP contabo

Endpoint

POST https://contabo-vps.taild7e69a.ts.net/ksearch/api/ksearch

Data source: Curated knowledge base: 6 Vietnam agriculture/enzyme guides + 5 trade intelligence guides, SQLite FTS5

Parameters

Param	Type	Description
`query`	string (body JSON)	Search query, e.g. 'durian fertilizer schedule'
`lang`	string (body JSON, optional)	Language code: vi, en, zh, th, id, ms, hi, ru, fr
`limit`	integer (body JSON, optional)	Max results, default 5

Example request

curl -X POST "https://contabo-vps.taild7e69a.ts.net/ksearch/api/ksearch" \
  -H "Content-Type: application/json" \
  -d '{\n "query": "durian fertilizer schedule",\n "lang": "en",\n "limit": 3\n}'

Example response

{\n  "query": "durian fertilizer schedule", "resultCount": 3,\n  "results": [{"source": "Vietnam Food Export Playbook", "section": "4.4 Lab Testing", "lang": "en", "excerpt": "..."}]\n}

How payment works (x402)

Call the endpoint without any payment header → you get 402 Payment Required with the exact price, the USDC contract, the network (eip155:8453 = Base), and the pay-to address.
Pay 0.01 USDC on Base to the pay-to address — with any wallet, the Coinbase CDP x402 SDK, or any x402 client library.
Retry the same request with the X-PAYMENT header set to the base64-encoded signed payment payload → 200 with JSON.

# 1. Get the 402 payment requirements
curl -s -X POST "https://contabo-vps.taild7e69a.ts.net/ksearch/api/ksearch" -H "Content-Type: application/json" -d '{\n "query": "durian fertilizer schedule",\n "lang": "en",\n "limit": 3\n}'

# 2. Pay 0.01 USDC on Base, then retry with the payment proof
curl -X POST "https://contabo-vps.taild7e69a.ts.net/ksearch/api/ksearch" \
  -H "Content-Type: application/json" \
  -H "X-PAYMENT: <base64-signed-payment-payload>" \
  -d '{\n "query": "durian fertilizer schedule",\n "lang": "en",\n "limit": 3\n}'

Facilitators: Coinbase CDP and PayAI (no API key needed for either). Scheme: x402 v2 exact. Asset: USDC 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base.

Free trial

Every IP gets 5/day free calls to this endpoint — no payment needed. Free calls run automatically when you call without an X-PAYMENT header. The X-Free-Remaining response header shows how many free calls you have left today. When the quota is exhausted, the request falls through to the normal 402 payment flow.

FAQ

Which languages are supported?
9 languages: Vietnamese, English, Chinese, Thai, Indonesian, Malay, Hindi, Russian, French. Use the lang parameter to filter.

What is in the knowledge base?
2,438 chunks from 6 Vietnam agriculture/enzyme guides and 5 trade intelligence guides.

How is relevance ranked?
SQLite FTS5 full-text ranking over the curated corpus.

Do I need an API key?
No. This API uses x402: call the endpoint, receive a 402 Payment Required with the price, pay in USDC on Base, and retry with the X-PAYMENT header. No signup, no API key, no account.

Which facilitators are supported?
Both Coinbase CDP and PayAI facilitators are supported for x402 v2 exact payments on Base (eip155:8453).

What if my payment is too low?
The facilitator verifies the on-chain amount against the price. If underpaid, you get 402 again; pay the full amount and retry.

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