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Quick Start

Features

Automatic Validation

The builder validates messages before building:

Field Formatting

Fields are automatically formatted based on their definitions:
  • Numeric fields: Left-padded with zeros
  • Alphanumeric fields: Right-padded with spaces (where required)
  • Terminal ID (41): Right-padded to 8 characters
  • Merchant ID (42): Right-padded to 15 characters

Variable-Length Fields

LLVAR and LLLVAR fields get automatic length prefixes:

Bitmap Generation

The bitmap is automatically generated from present fields:

Network-Aware Building

Specify network for network-specific field formatting:

Building Process

  1. Field Processing: Format each field value based on definition
  2. Validation: Validate message structure and field content
  3. MTI: Append 4-character MTI
  4. Bitmap: Generate and append bitmap from present fields
  5. Fields: Append each field with length prefix (if variable)

Common Field Examples

Authorization Request (0100)

Financial Request (0200)

Reversal (0400)

Error Handling

Common errors:
  • Missing required fields
  • Invalid field format
  • Field value exceeds maximum length

API Reference

See Core API Reference for complete API documentation.