x402 · Base · USDC

Prediction & anomaly detection
for AI agents

Send a list of numbers. Get the next predicted value or a list of anomalous points. Paid per call via x402 micropayments — no API keys, no accounts, no monthly bills.

Quick start OpenAPI spec →
$0.01 per call
USDC currency · Base network
2 paid endpoints
3–1000 series length

Quick start

Predict next value · POST /timeseries

POST https://easy-predict.com/timeseries
Content-Type:        application/json
PAYMENT-SIGNATURE:   <x402-signed-payment-payload>
// X-PAYMENT: <...> also accepted (legacy alias)

{
  "series": [1.0, 2.3, 4.1, 6.8, 9.2]
}

// 200 OK
{
  "prediction":      12.1,
  "method":          "linear",
  "holdout_errors":  { "linear": 0.05, "log1p-linear": 0.31, "last-delta": 0.05, "mean": 3.5 },
  "slope":           1.94,
  "intercept":       0.12
}

Detect anomalies · POST /anomaly-detection

POST https://easy-predict.com/anomaly-detection
Content-Type:        application/json
PAYMENT-SIGNATURE:   <x402-signed-payment-payload>
// X-PAYMENT: <...> also accepted (legacy alias)

{
  "series":    [1.0, 2.3, 4.1, 6.8, 99.0],
  "threshold": 2.0
}

// 200 OK
{
  "anomalies":  [{ "index": 4, "value": 99.0, "z_score": 2.14 }],
  "method":     "z-score",
  "mean":       15.12,
  "std":        39.18,
  "threshold":  2.0
}

No payment · 402 Payment Required

{
  "x402Version": 2,
  "error":       "Payment Required",
  "accepts": [{
    "scheme":           "exact",
    "network":          "eip155:8453",
    "asset":            "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
    "amount":           "10000",
    "payTo":            "0xc99b83818c8865340AC55C45554f377f41c68DBC"
  }]
}

Endpoints

POST /timeseries x402 · $0.01 USDC

Accepts {"series": [n, …]} or a bare JSON array (3–1000 numbers). Automatically selects the best model — linear, log1p-linear, last-delta, or mean — by holding out the last point as a validation target, then retrains the winner on the full series. Response includes holdout_errors for all candidates so you can see why the model was chosen. Calls without a valid PAYMENT-SIGNATURE header receive HTTP 402 with the full payment requirements in the response body. (X-PAYMENT is accepted as a legacy alias.)

POST /anomaly-detection x402 · $0.01 USDC

Accepts {"series": [n, …], "threshold": 2.0} or a bare JSON array (3–1000 numbers). Returns a list of anomalous points using z-score detection. Optional threshold (default 2.0, range 0–10) controls sensitivity — lower flags more points.

GET /openapi.json free

OpenAPI 3.1 spec. Paid operations declare the x402 security scheme; free operations declare "security": [].

GET /.well-known/x402 free

Machine-readable x402 resource list with full PaymentRequirements for each paid endpoint. Used by x402scan and other crawlers.

How x402 payment works

1
Your agent sends POST /timeseries or /anomaly-detection with no payment. The API returns HTTP 402 with the exact payment terms (network, asset, amount, recipient) in the accepts array.
2
Your agent signs the payment. Use any x402-compatible wallet or the x402 SDK to create a signed EIP-712 transfer for 0.01 USDC on Base.
3
Your agent resends with PAYMENT-SIGNATURE. Include the base64-encoded signed payload in the PAYMENT-SIGNATURE header (X-PAYMENT also accepted as a legacy alias). The facilitator verifies and settles on-chain.
4
You get the result. HTTP 200 with prediction (timeseries) or anomalies (anomaly-detection).

Agent integration example

Claude agent with autonomous x402 payments

A working Python agent that receives a natural-language forecasting task, calls this API, handles the 402 challenge, signs a $0.01 USDC payment on Base, and reports the result — all autonomously. Uses the Anthropic SDK with tool use. The same pattern works in LangChain, LlamaIndex, CrewAI, AutoGen, or any framework that supports custom tool implementations. 

# install
pip install anthropic requests eth-account

# run (live payments)
ANTHROPIC_API_KEY=sk-... WALLET_PRIVATE_KEY=0x... python demo_agent.py
View on GitHub llms.txt

Discovery

This API is discoverable by x402-compatible indexers via two standard documents.

OpenAPI 3.1 /openapi.json Full schema, security schemes, and x402 payment info per operation. x402 Discovery /.well-known/x402 Machine-readable list of paid resources with PaymentRequirements.