Struct Field20 

pub struct Field20 {
    pub reference: String,
}

Field 20: Sender’s Reference

Purpose

Specifies the reference assigned by the Sender to unambiguously identify the message. This reference must be unique within the sender’s system and is used to link related messages and confirmations throughout the payment chain.

Format

• Swift Format: 16x
• Description: Up to 16 alphanumeric characters
• Pattern: May include letters, digits, and limited special characters
• Restrictions: Must not start or end with / and must not contain //

Presence

• Status: Mandatory in all MT messages containing this field
• Swift Error Codes: T26 (invalid format), T13 (field too long)
• Referenced in Rules: Network validation rules across multiple message types

Network Validation Rules

• Format Validation: Must conform to 16x pattern (alphanumeric, max 16 chars)
• Content Validation: Cannot start/end with / or contain consecutive slashes //
• Uniqueness: Should be unique within sender’s daily operations for audit purposes

Usage Rules

• Confirmations: Must be quoted unchanged in related MT900/MT910/MT950 messages
• Cover Payments: When using cover method, copy to field 21 of associated MT202 COV
• Audit Trail: Used by institutions to track payment lifecycle and exceptions
• Reference Format: Common patterns include transaction IDs, invoice numbers, or internal references

Examples

:20:PAYMENT123456
:20:INV2024001234
:20:TXN20240719001
:20:URGPAY240719

Related Fields

• Field 21: Transaction Reference Number (often contains Field 20 value in cover payments)
• Field 61: Statement Line Reference (in account statements)
• Block 3 {108}: Message User Reference (system-level tracking)

STP Compliance

Field 20 has no specific STP restrictions but must meet standard format requirements. STP processing relies on this field for automated matching and exception handling.

See Also

• Swift FIN User Handbook: Message Structure and Field Specifications
• MT103 Specification: Customer Credit Transfer requirements
• Cover Payment Guidelines: Field 20/21 relationship rules

Fields

reference: String

The sender’s reference string (max 16 characters)

Format: 16x - Up to 16 alphanumeric characters Validation: No leading/trailing slashes, no consecutive slashes

Trait Implementations

impl Clone for Field20

fn clone(&self) -> Field20

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Field20

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for Field20

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl PartialEq for Field20

fn eq(&self, other: &Field20) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Serialize for Field20

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl SwiftField for Field20

fn parse(value: &str) -> Result<Self>

Parse field value from string representation

fn to_swift_string(&self) -> String

Convert field back to SWIFT string format

fn format_spec() -> &'static str

Get field format specification

fn parse_with_variant( value: &str, _variant: Option<&str>, _field_tag: Option<&str>, ) -> Result<Self>

where Self: Sized,

Parse field value with variant hint for enum fields Default implementation falls back to regular parse

fn valid_variants() -> Option<Vec<&'static str>>

Get valid variant letters for enum fields Returns None for non-enum fields, Some(vec) for enum fields

impl StructuralPartialEq for Field20