Read-Only EVM Contract Call
Execute one bounded eth_call against Base, Ethereum, or Arbitrum and return raw deterministic call data without signing or broadcasting.
Preview request
The preview path is rate-limited and does not charge. Production requests use the same parameters and return a standard x402 challenge when no payment signature is present.
curl --request POST \
"https://ai-data-marketplace-1042299154756.us-central1.run.app/api/v1/evm_call?preview=true" \
--header "content-type: application/json" \
--data '{"chain":"base","to":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","data":"0x18160ddd","block":"latest"}'Input contract
| Parameter | Type | Required | Description |
|---|---|---|---|
chain | string | No | base, ethereum, or arbitrum; defaults to base. |
to | string | Yes | Destination contract address. |
data | string | No | 0x-prefixed calldata, limited to 32,768 bytes; defaults to 0x. |
from | string | No | Optional caller address for call context. |
block | string | No | Block tag or height; defaults to latest. |
Example deliverable
This is the documented response shape, not a promise that live values will match the example. The paid request returns current or declared-source results using the same contract.
{
"success": true,
"network": "base",
"broadcast": false,
"return_data": "0x...",
"return_data_bytes": 32
}Purchase decision
Buy when: the active task needs this product's structured result, its declared source and freshness are sufficient, and 0.002 USDC is within the buyer's authorized per-request limit.
Skip when: a cached result is sufficient, the source or fields do not satisfy the task, or the buyer has not authorized payment. Do not bypass wallet, budget, or user-approval policy.
Guaranteed response metadata
Every successful product response identifies how the result was produced. Product-specific output fields are documented in the paid OpenAPI contract and can be inspected through the preview request where available.
{
"marketplace_metadata": {
"data_mode": "live_source",
"billable": true,
"availability": "operational",
"source": "public EVM JSON-RPC"
}
}Agent payment flow
Fast path: install the public MCP package, configure a dedicated low-balance Base buyer wallet and a maximum per-request spend, then call this tool with auto_pay: true. The client handles the challenge, local signature, settlement, and retry in one tool call.
npx -y dopaminedesk-ai-data-marketplace-mcp
X402_AUTO_PAY=true
X402_EVM_PRIVATE_KEY=<dedicated buyer wallet key>
X402_MAX_PAYMENT_USDC=0.25
tool input: { "auto_pay": true }Manual path: request the product, read the base64 PAYMENT-REQUIRED challenge, sign with any compatible x402 v2 client, and retry with PAYMENT-SIGNATURE. A successful response includes PAYMENT-RESPONSE.