Parse Validate Convert ISO20022 ISO15022 SWIFT MT MX messages

Decoding the Legacy — ISO 15022 (SWIFT MT)

ISO 15022 is a tag-based text format used primarily for securities and cash transfers (MT 5xx and MT 1xx series). It is governed by "Blocks" and "Sequences."

1. The Architecture

An MT message consists of five blocks. Most business logic resides in Block 4, which is delimited by {4: and -}.

Tags: 3-character codes (e.g., 20C, 98A).

Qualifiers: Distinguish the purpose of a tag (e.g., ::PREP for preparation date).

Sequences: Enclosed between :16R: (Start) and :16S: (End).

The Modern XML Standard — ISO 20022 (SWIFT MX)

ISO 20022 is the successor to MT, utilizing XML (eXtensible Markup Language). It is more verbose but offers significantly better data granularity and global standardization.

1. The Architecture

Instead of tags, MX messages use nested elements.

Group Header (GrpHdr): Metadata about the sender, receiver, and message ID.

Payment Information (PmtInf): The core instruction logic.

Namespaces: Crucial for distinguishing between different message versions (e.g., pain.001.001.03 vs pain.001.001.09).

2. The Implementation Snippet

Using SimpleXMLElement and XPath allows you to "jump" to the data you need without traversing the whole tree.