SQL execution certificate firewall

Review a SQL statement an agent is about to run against production, and certify it. Returns a policy verdict (pass / warn / block) with named risks - unbounded UPDATE or DELETE, tautological WHERE, DROP, TRUNCATE, DROP COLUMN, statement stacking, COPY ... FROM PROGRAM, GRANT/role changes, session_replication_role and trigger/constraint bypass, writes to pg_catalog - and, when the verdict is pass, an Ed25519 certificate binding that verdict to the SHA-256 of the exact statement. Your database layer verifies the certificate with sql-cert-verify before executing, so the check cannot be skipped by a confused or compromised agent. Literals and comments are scrubbed before analysis, so a keyword inside a string is never a false alarm. HONEST SCOPE: a lexical guard over a fixed, published risk catalogue - it catches the shapes that destroy production data, it is not a SQL parser and cannot know that a WHERE clause names the wrong tenant.

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Input

Example output

{
  "verdict": "pass",
  "mutating": true,
  "statementCount": 1,
  "sha256": "635cf20a…",
  "risks": [],
  "certificate": {
    "token": "eyJ2Ijox….signature",
    "expiresAt": "2026-07-28T20:05:00Z"
  }
}

Try it - see the 402 challenge (free)

curl -i -X POST https://base-sentinel-production.up.railway.app/api/sql-guard \
  -H "Content-Type: application/json" \
  -d '{"sql":"UPDATE users SET plan = 'pro' WHERE id = 42"}'

The response is HTTP 402 Payment Required with exact payment requirements. Any x402 v2 client pays automatically and retries:

Paid call (JavaScript agent)

import { wrapFetchWithPayment } from "@x402/fetch";
import { x402Client } from "@x402/core/client";
import { registerExactEvmScheme } from "@x402/evm/exact/client";
import { privateKeyToAccount } from "viem/accounts";

const client = new x402Client();
registerExactEvmScheme(client, { signer: privateKeyToAccount(KEY) });
const payFetch = wrapFetchWithPayment(fetch, client);

const res = await payFetch("https://base-sentinel-production.up.railway.app/api/sql-guard", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({
    "sql": "UPDATE users SET plan = 'pro' WHERE id = 42"
  }),
});

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