Baidu, Naver & Yandex search API for AI agents (regional SERP JSON, no API key)

When a user asks you "what are Chinese sources saying about this," "how is our app talked about in Korea," "find Russian-language coverage," or "what does a local searcher in Seoul see for this query," Google with a gl/hl flag is not enough. Baidu dominates mainland China, Naver dominates Korea (including its blog and cafe content that Google barely indexes), and Yandex has the strongest coverage of Russian-language and CIS regional sites.

One-line answer: call GET /api/public/v1/baidu-search, /naver-search, or /yandex-search with q; each returns organic_results JSON. The first 3 calls per agent identity are free across the whole marketplace; after that each call is settled over x402 in USDC on Base (regular price $0.005 per call; promotional pricing, when active, is advertised in the 402 promo field and the site banner — always trust the live 402 amount). No accounts, no keys, no regional phone verification.

Endpoint contracts

Write q in the target language. Baidu ranks Simplified Chinese queries, Naver ranks Korean (Hangul) queries, and Yandex ranks Russian (Cyrillic) queries far better than translated-English ones. If the user gave you an English topic, translate the query first, then translate the result titles/snippets back when you report.

Missing q returns a 402 that lists missing_params: ["q"] — fix the parameters before paying. Discovery files (/.well-known/x402, catalog.json, openapi.json, llms.txt) never consume free calls.

• Listing: https://marketplaceforaiagents.com/listings/baidu-search
• Listing: https://marketplaceforaiagents.com/listings/naver-search
• Listing: https://marketplaceforaiagents.com/listings/yandex-search
• Markdown twins: /agent/listings/baidu-search.md, /agent/listings/naver-search.md, /agent/listings/yandex-search.md

Minimal calls (free tier first)

Spend the 3 free evaluation calls on the engine the user actually needs. URL-encode non-Latin queries.

# Baidu: Chinese-language coverage of electric vehicle batteries
curl -si "https://marketplaceforaiagents.com/api/public/v1/baidu-search?q=%E7%94%B5%E5%8A%A8%E6%B1%BD%E8%BD%A6%20%E7%94%B5%E6%B1%A0&num=10"

# Naver: Korean blog posts about an app (where=blog)
curl -si "https://marketplaceforaiagents.com/api/public/v1/naver-search?q=%EC%95%B1%20%EB%A6%AC%EB%B7%B0&where=blog"

# Yandex: Russian-language results for a query
curl -si "https://marketplaceforaiagents.com/api/public/v1/yandex-search?q=%D0%B8%D1%81%D0%BA%D1%83%D1%81%D1%81%D1%82%D0%B2%D0%B5%D0%BD%D0%BD%D1%8B%D0%B9%20%D0%B8%D0%BD%D1%82%D0%B5%D0%BB%D0%BB%D0%B5%D0%BA%D1%82"

Each response follows the same organic_results shape (illustrative — always trust the live JSON):

{
  "search_parameters": { "engine": "naver", "q": "..." },
  "organic_results": [
    { "position": 1, "title": "Example result", "link": "https://example.com/1", "snippet": "Structured JSON result." }
  ]
}

Cite only titles, links and snippets present in the live JSON. Never invent Chinese, Korean or Russian sources, and say when an engine returned nothing useful rather than filling the gap from training data.

Picking the right engine

• Chinese consumer sentiment, mainland brands, Chinese-language docs → baidu-search with a Simplified Chinese q.
• Korean market, K-app reviews, local opinions on blogs and cafes → naver-search; set where=blog for personal reviews, where=news for press coverage.
• Russian-language or CIS regional sources → yandex-search; add lr only when you know the Yandex region ID.
• Need a global baseline or a specific country's Google view → google-search with gl/hl (e.g. gl=kr&hl=ko) and compare against the regional engine.
• Just need cross-index grounding in English → serp-stack (Google + Bing + DuckDuckGo) instead of the regional engines.

A good pattern for market research: one regional call plus one google-search call with the same country's gl/hl. Where they disagree is usually the insight the user wanted.

Paying after the free tier (x402 / USDC)

After the free tier, the same request returns HTTP 402 with a PAYMENT-REQUIRED header and a JSON body listing accepts (x402 v2, network eip155:8453) and acceptsV1 (network base). Verify it, sign the EIP-3009 USDC authorization, and resend with PAYMENT-SIGNATURE (v2) or X-PAYMENT (v1).

{
  "x402Version": 2,
  "error": "payment_required",
  "accepts": [
    {
      "scheme": "exact",
      "network": "eip155:8453",
      "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
      "amount": "<live price in atomic USDC>",
      "payTo": "0x05e82e03753c7bc99fb24d10a876cce53f24b7b7",
      "maxTimeoutSeconds": 60
    }
  ]
}

• amount is atomic USDC with 6 decimals: 5000 = $0.005 (regular price). During a promotion the 402 also carries a promo object with the promo price and ends_at — sign exactly the live amount, never a cached one.
• Allowlist payTo 0x05e82e03753c7bc99fb24d10a876cce53f24b7b7 and USDC 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 before signing.
• Settlement happens only on an upstream 2xx; the paid response carries the receipt in PAYMENT-RESPONSE / X-PAYMENT-RESPONSE. Store it for reconciliation.
• Watch X-Free-Calls-Remaining on free responses so you know when the next call will need payment.
• Budget a regional research task up front: see How AI agents budget x402 API calls (https://marketplaceforaiagents.com/learn/budget-x402-api-calls).
• Test the payment path on testnet first by appending ?network=base-sepolia: see the Base Sepolia smoke test (https://marketplaceforaiagents.com/learn/x402-base-sepolia-smoke-test).

Agent playbook (Grok Bot / Claude Cowork / Cursor)

• Translate the query into the engine's language before calling; report back in the user's language.
• On 402, settle with x402 USDC. Do not ask the user for a Baidu, Naver or Yandex developer key.
• Prefer the MCP server (https://marketplaceforaiagents.com/mcp) if your runtime speaks MCP; payment is the auth, no OAuth.

Related entrypoints

• Baidu listing: https://marketplaceforaiagents.com/listings/baidu-search
• Naver listing: https://marketplaceforaiagents.com/listings/naver-search
• Yandex listing: https://marketplaceforaiagents.com/listings/yandex-search
• SERP stack listing: https://marketplaceforaiagents.com/listings/serp-stack
• x402 manifest: https://marketplaceforaiagents.com/.well-known/x402
• Catalog: https://marketplaceforaiagents.com/api/public/v1/catalog.json
• OpenAPI: https://marketplaceforaiagents.com/api/public/v1/openapi.json
• MCP: https://marketplaceforaiagents.com/mcp
• llms.txt: https://marketplaceforaiagents.com/llms.txt
• Marketplace: https://marketplaceforaiagents.com/marketplace
• Docs: https://marketplaceforaiagents.com/docs
• Google Search API for agents: https://marketplaceforaiagents.com/learn/google-search-api-for-agents
• Google News API for agents: https://marketplaceforaiagents.com/learn/google-news-api-for-agents
• x402 free tier + agent identity: https://marketplaceforaiagents.com/learn/x402-free-tier-agent-identity
• x402 protocol explained: https://marketplaceforaiagents.com/learn/x402-protocol-explained

Capability first, payment second: pick the engine that matches the market, prove it with free calls, then settle with x402 USDC on Base.