Free Online Barcode Generator
Generate standard 1D barcodes in Code 128, EAN-13, UPC-A, and Code 39 formats downloadable as high-resolution PNGs.
Enter Data
Enter any text or a URL to convert it into a Bar code. The generator calls your live API endpoint.
Bar Code Result
Your generated Bar code will appear here.
Technical Architecture: Reverse-Engineering 1D Barcode Symbologiesā
Linear (1D) barcodes represent alphanumeric characters through parallel combinations of variable-width bars and spaces conforming to international standards (ISO/IEC 15417 for Code 128, ISO/IEC 15420 for EAN/UPC).
1. Code 128 Symbology & Modulo 103 Checksumā
Code 128 is a high-density alphanumeric symbology utilizing three distinct subsets:
- Subset A: Standard ASCII, control codes, and capital letters.
- Subset B: Standard ASCII, uppercase and lowercase letters, and punctuation.
- Subset C: Double-density numeric pairs (
00through99), reducing bar count by 50% for numeric sequences.
Each character consists of 11 module units structured into three bars and three spaces. Integrity is guaranteed via a modulo-103 weighted checksum:
Checksum = (StartCodeValue + Ī£(CharacterValue_i Ć i)) mod 103
Where i denotes the 1-based character position in the data string. The computed checksum symbol is appended immediately before the Stop character.
2. GS1 EAN-13 & UPC-A Check Digit Algorithmā
Retail barcodes (EAN-13 and UPC-A) use a modulo-10 checksum with alternating 3x and 1x weights computed from right to left across the payload:
Sum = 3 Ć (dā + dā + dā + ...) + 1 Ć (dā + dā + dā
+ ...)
CheckDigit = (10 - (Sum mod 10)) mod 10
This mathematical validation prevents scanner misreads caused by label damage, smudges, or optical skew.
3. Programmatic API Endpoint & Telegram Bot Integrationā
Barcodes can be integrated into automated shipping workflows, warehouse printers, or Telegram bots using our backend API:
# Generate a Code 128 barcode image via cURL
curl -o barcode.png "https://serhii-bots-empire.vercel.app/barcode/generate?data=hrekov.com"
Query Parametersā
| Parameter | Type | Required | Description |
|---|---|---|---|
data | string | Yes | The numeric or alphanumeric text to encode. |
format | string | No | Barcode symbology (e.g., code128, ean13, upca). Default: code128. |
Telegram Bot Automationā
For instant barcode generation on mobile devices, use the dedicated Telegram bot:
- Bot Username:
@responseWithBarcodeBot - Features: Send any alphanumeric text or product SKU in a chat message and receive an instant, high-contrast barcode PNG attachment.
Supported Barcode Symbologies Comparisonā
| Symbology | Data Type | Character Set | Standard Checksum | Primary Industry Use Case |
|---|---|---|---|---|
| Code 128 | Alphanumeric | Full 128 ASCII characters | Modulo 103 | Logistics, supply chain, shipping carton labels |
| EAN-13 | Numeric | Exactly 12 digits + 1 check digit | Modulo 10 (GS1) | International retail products (Europe, Asia, Global) |
| UPC-A | Numeric | Exactly 11 digits + 1 check digit | Modulo 10 (GS1) | North American retail point of sale (POS) |
| Code 39 | Alphanumeric | Uppercase A-Z, 0-9, and 7 symbols | Modulo 43 (optional) | Automotive, healthcare, and US Department of Defense |
| ITF-14 | Numeric | Exactly 14 digits (Interleaved 2 of 5) | Modulo 10 | Corrugated cardboard master packing cases |
Client-Side Security & Zero-Server Data Isolationā
- Stateless Generation: Barcode requests are processed ephemerally in memory without persistent database logging, telemetry, or IP tracking.
- Label Ready: Downloaded PNG files maintain clean 1-bit monochrome rendering with exact bar-to-space ratios, preventing optical blur when sent to direct thermal label printers.
- Local Caching: Generated images can be copied directly to your clipboard or saved locally without intermediate cloud storage.
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