Barcode / QR decode

Decode a barcode or QR code from an image. Send POST /api/barcode-decode with the required field image and pay $0.001 per call over x402 or MPP, or call it free by solving a proof-of-work challenge. It returns a JSON object with found, format, text and decoder.

Send a base64 PNG or JPEG (or a data: URL); returns the decoded text and the symbology. Reads QR, DataMatrix, and 1D barcodes (EAN/UPC/Code39/Code128/ITF/Codabar). Deterministic, no network, no model.

Category: Live public data · Tags: barcode qr qr-code decode scanner ean upc datamatrix

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Parameters

Example request

curl -i -X POST https://agent402.tools/api/barcode-decode \
  -H "Content-Type: application/json" \
  -d '{"image":"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"}'

Without payment this returns HTTP 402 Payment Required with the exact price for barcode-decode; any x402 v2 or MPP client pays it and retries.

Example response

{
  "found": true,
  "format": "QR_CODE",
  "text": "AGENT402",
  "decoder": "zxing"
}

From an MCP client

catalog.call {
  "slug": "barcode-decode",
  "params": {
    "image": "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"
  }
}

On the hosted connector at https://agent402.tools/mcp, catalog.call runs barcode-decode free (rate-limited, no wallet). Local install: npx -y agent402-mcp.

Errors and behavior

• image is required. An input the tool rejects returns an HTTP 4xx whose body carries error, tool, expected, required and example, so the caller can correct it.
• A paid call that ends in any status of 400 or above is not charged over x402, MPP or a prepaid credits key: settlement is cancelled when the tool fails. The exception is a Tempo push credential, a transfer the buyer sent before the call: it settles before the tool runs, so if the tool then fails the payment is recorded as a refund owed to the paying wallet.
• Free tier: no outbound network call leaves the server for this tool, so proof-of-work (16 leading zero bits of sha256) pays for it.
• A GET or HEAD to /api/barcode-decode returns the same 402 quote, so the price can be read without a body.
• An Idempotency-Key header makes a retried paid call replay the first 200 instead of charging again (an answer larger than 1 MB is not replayed).

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();
client.setSpendControls?.(false); // keep your own spending ceiling in code
registerExactEvmScheme(client, { signer: privateKeyToAccount(KEY) });
const payFetch = wrapFetchWithPayment(fetch, client);

const res = await payFetch("https://agent402.tools/api/barcode-decode", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({
    "image": "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"
  }),
});

No wallet? Pay with compute

Fetch a challenge, solve the sha256 puzzle (16 leading zero bits, a fraction of a second of CPU), and resend with the X-Pow-Solution header:

import { createHash } from "node:crypto";
const lz = (b) => { let t = 0; for (const x of b) { if (!x) { t += 8; continue; } t += Math.clz32(x) - 24; break; } return t; };
const c = await (await fetch("https://agent402.tools/api/pow/challenge?slug=barcode-decode")).json();
let n = 0;
while (lz(createHash("sha256").update(c.challenge + ":" + n).digest()) < c.difficulty) n++;
await fetch("https://agent402.tools/api/barcode-decode", { method: "POST", headers: { "X-Pow-Solution": c.token + ":" + n, "Content-Type": "application/json" }, body: JSON.stringify({"image":"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"}) });

Part of these workflows

Barcode / QR decode is one step in these 2 skill packs, each sold as a single call:

• Document intelligence - Turn any PDF or image URL into structured data - metadata, extracted text, sliced page ranges, OCR for scanned docs, decoded barcodes / QR codes - without falling back to a vision LLM guess. Built for the messy 30% of documents where pdf-to-markdown alone returns nothing useful.
• Uploaded-media normalize - The 'user uploaded a thing, normalize it before storing' workflow. Probe the file (image or audio/video) with media-info, decode any embedded barcodes/QRs, resize and thumbnail the image, convert it to a web-friendly format, and normalize audio loudness to broadcast standard. Six tools, one canonical normalize-on-upload pipeline that turns arbitrary user uploads into predictable storage artifacts.

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