# POST /sql/explain: $0.003 per call

Explain and sanity-check a SQL query before running it: statement type, tables touched, syntax problems (quotes, parentheses, = NULL), risky patterns (UPDATE/DELETE without WHERE, DROP, NOT IN with NULLs, cartesian joins, non-sargable filters, multiple statements) and a plain-English explanation. POST {sql, dialect}.

- **Price:** $0.003 in USDC, the same on Base, Solana, Polygon, Arbitrum. Failed calls are never charged.
- **Free trial:** yes, 20 free calls a day from Claude, Cursor or any MCP client ([set-up](/mcp/setup)).
- **Tier:** live
- **Answers cached for:** 1 day(s)
- **Data sources:** Local SQL checks; Workers AI (metered, small model)
- **Lane:** AI coding agents ([OpenAPI](/openapi/coding.json))
- **Live health:** [status page](/status)

## Free sample

See an answer for the demo input first, free (no payment, 10 a minute): [https://aayatai.com/sample/sql-explain](/sample/sql-explain). It is a stored real answer when we have one, otherwise an example marked `"kind": "illustrative"`.

```bash
curl "https://aayatai.com/sample/sql-explain"
```

## 1. See the price (free)

Call it without paying: you get `402 Payment Required` and a `PAYMENT-REQUIRED` header with the exact price and where to pay.

```bash
curl -i -X POST https://aayatai.com/sql/explain -H "content-type: application/json" -d '{"sql":"DELETE FROM users WHERE last_login < NOW() - INTERVAL '2 years'","dialect":"postgres"}'
```

## 2. Pay and call (TypeScript)

```bash
npm install @x402/fetch @x402/evm viem
```

```ts
import { wrapFetchWithPaymentFromConfig } from "@x402/fetch";
import { ExactEvmScheme } from "@x402/evm";
import { privateKeyToAccount } from "viem/accounts";

// A wallet used only by your agent, holding a little USDC on Base.
const account = privateKeyToAccount(process.env.WALLET_PRIVATE_KEY as `0x${string}`);
const pay = wrapFetchWithPaymentFromConfig(fetch, {
  schemes: [{ network: "eip155:8453", client: new ExactEvmScheme(account) }],
});

const res = await pay("https://aayatai.com/sql/explain", {
  method: "POST",
  headers: { "content-type": "application/json" },
  body: JSON.stringify({"sql":"DELETE FROM users WHERE last_login < NOW() - INTERVAL '2 years'","dialect":"postgres"}),
});
console.log(await res.json());
```

## 3. Or as an MCP tool

```ts
// MCP server: https://aayatai.com/mcp (Streamable HTTP). With the x402 MCP client (see /start):
const result = await client.callTool("sql-explain", {"sql":"DELETE FROM users WHERE last_login < NOW() - INTERVAL '2 years'","dialect":"postgres"});
```

## Inputs

- `sql` **(required)** (string): The SQL to check.
- `dialect` (string; one of `postgres`, `mysql`, `sqlite`, `sqlserver`, `generic`; default `generic`): SQL dialect (used in the explanation).

Bad inputs are rejected with HTTP 400 before any payment is asked for.

## Example answer

```json
{
  "valid": true,
  "type": "DELETE",
  "statements": 1,
  "tables": [
    "users"
  ],
  "findings": [],
  "verdict": "ok",
  "explanation": "Deletes every user whose last login was more than two years ago."
}
```

## Related

- [GET /docs/find](/services/docs-find) ($0.003): Find the AI-ready docs for any library or API: checks the project's docs site (from its npm, PyPI, crates or Go metadata) or any company domain (docs., develope
- [GET /docs/lib](/services/docs-lib) ($0.005): Up-to-date docs for any npm, PyPI, crates or Go library, trimmed for a coding agent's context: finds the project's own llms.txt and docs pages (or the latest re
- [POST /docs/answer](/services/docs-answer) ($0.02): Ask a coding question about any npm, PyPI, crates or Go library and get an answer written only from its current docs (project llms.txt, docs pages or latest REA
- [GET /openapi](/services/openapi) ($0.005): Understand any public API fast: give its OpenAPI/Swagger spec URL, its docs or base URL, or a name from the APIs.guru directory (?api=stripe.com); we find the s
- [GET /library/research](/services/library-research) ($0.10): Premium research report on a library or API for coding agents: reads its current docs for your goal, checks version, safety and repository health, gathers what 
- [GET /package/check](/services/package-check) ($0.005): Should a coding agent install this package?
- [GET /dependency/verdict](/services/dependency-verdict) ($0.03): "Should I use this dependency?" in one call for npm, PyPI, crates or Go: full package safety check (vulnerabilities, malware, typosquats, deprecation, licence, 
- [GET /dependency/report](/services/dependency-report) ($0.08): Premium "should I use this dependency?" report: package safety (vulnerabilities, malware, typosquats, deprecation), GitHub repository health, licence compatibil

New here? [Getting started in 60 seconds](/start). All services: [Aayat AI](/).