ISO 8583 Parser

Parse ASCII ISO 8583:1987 messages — decode the MTI, primary, secondary and tertiary bitmaps, and every present data element with its ISO field format. Paste the message as text or as a hex dump; BCD and EBCDIC encodings are not supported.

Follows ISO 85831987·verified Oct 2026· double-checked Oct 2026— ASCII encoding; DE 55 as ISO 8583:1993 b..255 LLLVAR; bit 65 read as a tertiary-bitmap flag (implementation convention)

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ISO 8583 message (ASCII text, or hex dump of the wire bytes)

Field formats follow ISO 8583:1987 (DE 55 as the ISO 8583:1993 ICC data field, b..255 LLLVAR). In 1987, DE 65 is "Bit map, extended" (b 1); this parser instead reads a set bit 65 as a third, tertiary bitmap (DE 129–192), as some implementations do.

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Standards & Guides

📦ISO 8583 Reference 📖ISO 8583 Deep Dive 💰Settlement Guide