SWIFT MT Message Type Validation in Python — Categories & Lookup

1. What are SWIFT MT messages?

SWIFT (Society for Worldwide Interbank Financial Telecommunication) operates the global messaging network that financial institutions use to send and receive structured instructions about transactions. MT stands for Message Type — the legacy format that has been the backbone of international payments, securities, trade finance, and treasury operations for decades.

Each MT message is identified by a three-digit number (e.g. MT103, MT202, MT940). The first digit indicates the category — the broad functional area the message belongs to — while the remaining digits identify the specific message type within that category.

2. MT message categories

Every MT message type is assigned to one of ten categories (0–9). The first digit of the three-digit type number determines the category:

The most commonly encountered types in everyday banking are MT103 (single customer credit transfer), MT202 (general financial institution transfer), MT940 (customer statement), MT760 (guarantee / standby letter of credit), and MT700 (issue of a documentary credit).

3. Common MT message types

Below is a detailed look at the most frequently used message types across categories:

4. Why MT validation matters

5. The right solution: validate + list

The IsValid SWIFT MT API provides two endpoints: one to validate and look up a specific MT type, and another to list all known types — optionally filtered by category.

Get your free API key at isvalid.dev — 100 calls per day, no credit card required.

Full parameter reference and response schema: SWIFT MT Validation API docs →

6. Python code examples

Using the isvalid Python SDK or the requests library.

Validate a message type

# swift_mt_validator.py
import os
from isvalid import create_client

iv = create_client(api_key=os.environ["ISVALID_API_KEY"])

# ── Validate a single MT message type ────────────────────────────────────────

result = iv.swift_mt("MT103")

if not result["valid"]:
    print("Unknown MT message type")
else:
    print(f"Type: {result['type']}")            # MT103
    print(f"Category: {result['category']}")     # 1
    print(f"Group: {result['group']}")            # Customer Payments & Cheques
    print(f"Description: {result['description']}")
    # → Single Customer Credit Transfer

List message types by category

# swift_mt_list.py
import os
from isvalid import create_client

iv = create_client(api_key=os.environ["ISVALID_API_KEY"])

# ── List all message types ───────────────────────────────────────────────────

all_types = iv.swift_mt.list()
print(f"Total MT types: {len(all_types)}")

# ── Filter by category ──────────────────────────────────────────────────────

payment_types = iv.swift_mt.list(category=1)

for mt in payment_types:
    print(f"  {mt['type']:<8} {mt['description']}")
# → MT101    Request for Transfer
# → MT103    Single Customer Credit Transfer
# → ...

7. cURL examples

Validate a specific MT message type:

curl -H "Authorization: Bearer YOUR_API_KEY" \
  "https://api.isvalid.dev/v0/swift-mt?value=MT103"

Validate using just the numeric part (without the MT prefix):

curl -H "Authorization: Bearer YOUR_API_KEY" \
  "https://api.isvalid.dev/v0/swift-mt?value=202"

List all message types in category 1 (Customer Payments & Cheques):

curl -H "Authorization: Bearer YOUR_API_KEY" \
  "https://api.isvalid.dev/v0/swift-mt/list?category=1"

List all known MT message types (no filter):

curl -H "Authorization: Bearer YOUR_API_KEY" \
  "https://api.isvalid.dev/v0/swift-mt/list"

8. Understanding the response

Validate endpoint response

Response for MT103:

{
  "valid": true,
  "type": "MT103",
  "category": 1,
  "group": "Customer Payments & Cheques",
  "description": "Single Customer Credit Transfer"
}

Response for an invalid type:

{
  "valid": false,
  "type": "MT999",
  "category": null,
  "group": null,
  "description": null
}

List endpoint response

Response for GET /v0/swift-mt/list?category=1 (truncated):

[
  {
    "type": "MT101",
    "category": 1,
    "group": "Customer Payments & Cheques",
    "description": "Request for Transfer"
  },
  {
    "type": "MT103",
    "category": 1,
    "group": "Customer Payments & Cheques",
    "description": "Single Customer Credit Transfer"
  },
  {
    "type": "MT110",
    "category": 1,
    "group": "Customer Payments & Cheques",
    "description": "Advice of Cheque(s)"
  }
]

9. Edge cases to handle

# All of these return the same result
iv.swift_mt("MT103")
iv.swift_mt("mt103")
iv.swift_mt("Mt103")
# → {"valid": True, "type": "MT103", ...}

# Both are equivalent
iv.swift_mt("MT202")
iv.swift_mt("202")
# → {"valid": True, "type": "MT202", ...}

# Build a migration inventory from your MT traffic
all_types = iv.swift_mt.list()

# Common MT → MX mappings
mt_to_mx_map = {
    "MT103": "pacs.008",
    "MT202": "pacs.009",
    "MT940": "camt.053",
    "MT101": "pain.001",
    "MT900": "camt.054",
    "MT910": "camt.054",
}

for mt in all_types:
    mx = mt_to_mx_map.get(mt["type"], "no direct mapping")
    print(f"  {mt['type']} → {mx}")