x402 · USDC · Base / Solana · No signup · No API key

Start at $0.003/call

DeepSeek V4 Flash is the cheap tip-of-spear for agents. Free hourly sample on default chat, then pay only when you need a fresh custom call. Six models on one OpenAI-compatible surface.

Free chat sample Model catalog (JSON) How to pay (402)

① DeepSeek V4 Flash

Fast, cheap OpenAI-compatible chat for high-volume agents. Best first paid call.

$0.003 / call

Free sample first

POST https://x402donghang.duckdns.org/x402/v1/models/deepseek-v4-flash/chat/completions
Content-Type: application/json

{"messages":[{"role":"user","content":"ping"}],"stream":false,"max_tokens":64}
Unpaid → HTTP 402 + payment requirements. Pay USDC → same request returns the model reply.

② Default Chat (Grok 4.5 High)

Flagship path for SDKs that hit /v1/chat/completions. Streaming supported.

$0.01 / call

Free sampleAll models

③ Crypto Radar

Live X + web intelligence, CoinGecko context, structured signals and citations.

$0.03 / call

Free sample

Crypto Brief · Summarize

Structured bias/thesis/risks, or URL/text → summary + actions.

$0.01 · $0.01

Brief sampleSummarize sample

Price ladder (chat)

Pick by job: Flash for volume → mid tier for reasoning → Claude for careful writing. Public names only.

ModelUSDC / callPOST path
DeepSeek V4 Flash best start$0.003/x402/v1/models/deepseek-v4-flash/chat/completions
DeepSeek V4 Pro$0.008/x402/v1/models/deepseek-v4-pro/chat/completions
GLM 5.2$0.008/x402/v1/models/glm-5.2/chat/completions
Grok 4.5 High default$0.01/x402/v1/chat/completions
Qwen 3.8 Max$0.012/x402/v1/models/qwen-3.8-max/chat/completions
Claude Sonnet 4.6$0.02/x402/v1/models/claude-sonnet-4.6/chat/completions

GET /x402/v1/models

How payment works

  1. Free first — hit a /sample URL. Cached hourly, no wallet.
  2. Custom call — POST the paid path. Server returns HTTP 402 with machine-readable PAYMENT-REQUIRED.
  3. Pay once — x402 client (AgentCash / @x402/fetch) signs USDC on Base or Solana and retries. No account, no API key.
  4. Get result — 200 + OpenAI-style chat JSON (or vertical product JSON).

Try free sample (10s)

curl -s https://x402donghang.duckdns.org/x402/v1/chat/completions/sample

Cheapest paid path (expect 402 without wallet)

curl -sS -D- -X POST 'https://x402donghang.duckdns.org/x402/v1/models/deepseek-v4-flash/chat/completions' \
  -H 'content-type: application/json' \
  -d '{"messages":[{"role":"user","content":"hi"}],"stream":false,"max_tokens":32}'

All samples (JSON)OpenAPIAgent integration

No signup. Unpaid calls return HTTP 402. Prices are per request in USDC. Not financial advice for crypto products.