API Documentation

Generate barcodes programmatically. Plug it into Claude Code, ChatGPT/Codex, Cursor, openclaw, Aider, Continue, or any AI agent that supports HTTP tool calls — drop the spec into your agent's tool definitions and let it generate, validate, and bulk-create barcodes on demand. Available on any paid plan; quota applies per tier.

Base URL

https://upcgen.com

Authentication

Every request must include an API key in the Authorization header:

Authorization: Bearer upcgen_live_xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

Manage API keys in your account dashboard.

Quick start

Render a UPC-A barcode as PNG:

curl -X POST https://upcgen.com/api/barcode \
  -H "Authorization: Bearer $UPCGEN_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"format":"upca","text":"036000291452","output":"png"}' \
  --output barcode.png

AI agent integration

The API is a clean fit for any AI coding agent that can call HTTP tools — Claude Code, ChatGPT / Codex, Cursor, openclaw, Aider, Continue, Cline, Roo Code, and anything MCP-compatible. Two endpoints, JSON in / JSON or image out, predictable errors.

Claude tool definition (function calling)

{
  "name": "upcgen_generate",
  "description": "Generate one or more valid barcodes (UPC-A, EAN-13, Code 128, FNSKU, etc.) with correct check digits. Returns codes as JSON or CSV.",
  "input_schema": {
    "type": "object",
    "properties": {
      "format": { "type": "string", "enum": ["upca","upce","ean13","ean8","isbn","itf14","code128","fnsku","datamatrix"] },
      "mode":   { "type": "string", "enum": ["random","sequential"], "default": "random" },
      "prefix": { "type": "string", "description": "Required when mode = sequential" },
      "count":  { "type": "integer", "minimum": 1, "maximum": 1000, "default": 1 },
      "output": { "type": "string", "enum": ["json","csv"], "default": "json" }
    },
    "required": ["format"]
  }
}

OpenAI / Codex tool definition

{
  "type": "function",
  "function": {
    "name": "upcgen_generate",
    "description": "Generate barcodes via UPCGen REST API. Use POST https://upcgen.com/api/generate with bearer auth.",
    "parameters": {
      "type": "object",
      "properties": {
        "format": { "type": "string", "enum": ["upca","upce","ean13","ean8","isbn","itf14","code128","fnsku","datamatrix"] },
        "count":  { "type": "integer", "minimum": 1, "maximum": 1000 }
      },
      "required": ["format"]
    }
  }
}

Store your UPCGEN_API_KEYin the agent's env so the bearer header is set automatically. Same OpenAPI shape works in Cursor (/api/tools/openapi.json), Aider (--openai-api-key with custom base), and any MCP server wrapping our REST API.

Endpoints

POST /api/barcode

Render a barcode image from a value you provide.

Request body:

{
  "format": "upca" | "upce" | "ean13" | "ean8" | "isbn" | "itf14" | "code128" | "fnsku" | "datamatrix",
  "text":   "036000291452",
  "output": "png" | "svg"      // optional, default "png"
}

Response:

Binary image body with the appropriate Content-Type.

POST /api/generate

Generate one or more valid codes with correct check digits. Optionally return a CSV.

Request body:

{
  "format": "upca",
  "mode":   "random" | "sequential",  // default "random"
  "prefix": "036000",                  // required when mode = "sequential"
  "count":  100,                       // 1..1000, default 1
  "output": "json" | "csv"             // default "json"
}

Response (JSON):

{
  "codes":  ["036000000016", "036000000023", ...],
  "mode":   "sequential",
  "count":  100,
  "format": "upca"
}

With output=csv, returns text/csv ready to save.

Code samples

Node.js

const res = await fetch("https://upcgen.com/api/generate", {
  method: "POST",
  headers: {
    "Authorization": `Bearer ${process.env.UPCGEN_API_KEY}`,
    "Content-Type": "application/json",
  },
  body: JSON.stringify({ format: "upca", mode: "random", count: 50 }),
});
const { codes } = await res.json();

Python

import os, requests

r = requests.post(
    "https://upcgen.com/api/generate",
    headers={"Authorization": f"Bearer {os.environ['UPCGEN_API_KEY']}"},
    json={"format": "ean13", "mode": "random", "count": 100, "output": "csv"},
)
open("codes.csv", "wb").write(r.content)

Rate limits

Quota is shared between UI and API usage on a rolling 30-day window:

• Starter: 100 codes / month
• Pro: 3,000 codes / month
• Business: 25,000 codes / month

When you exceed your quota, the API returns HTTP 429 with a JSON body explaining the reset.

Errors

Support

Questions, integration help, custom rate limits: [email protected]