Message Handling in SAP ABAP — Complete SE91 Message Classes Guide

When I wrote my first custom ABAP report for a real business user, I used WRITE statements to output error messages. If a vendor number didn’t exist, my program printed: “Error: Vendor not found.”

The senior developer reviewing my code stopped me immediately. “You can’t use WRITE statements for validation errors in SAP,” he explained. “What if a user runs this program in German? What if an external application calls your program via RFC? What if a batch job runs this overnight at 3 AM?”

A WRITE statement only works on an interactive screen for an English-speaking user. It fails completely in background jobs, APIs, multlingual environments, and automated error logs.

SAP solves this using Message Classes and the MESSAGE statement.

Message handling is how SAP communicates errors, warnings, information, and success notifications across all UI layers, APIs, and background processes.

This guide covers everything you need to know about creating message classes in transaction SE91, using different message types, passing dynamic placeholders, and handling messages in modern ABAP.

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What is a Message Class in SAP?

A Message Class is a central repository in the ABAP Dictionary that stores text messages, error notices, and system alerts.

Transaction code: SE91

Inside a message class, every message receives a unique 3-digit number (from 000 to 999).

Message Class: Z_MM_MESSAGES

Number │ Message Short Text
───────┼───────────────────────────────────────────────────
001    │ Vendor &1 does not exist in company code &2.
002    │ Purchase Order &1 saved successfully.
003    │ Quantity cannot be negative or zero.
004    │ Material &1 is blocked for procurement.

Notice the &1 and &2 in messages 001, 002, and 004. These are dynamic placeholders. At runtime, your ABAP code fills these placeholders with real data values (like actual vendor IDs or material numbers).

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Step-by-Step: Creating a Message Class in SE91

Here is how you create your own custom message class from scratch.

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Step 1: Open Transaction SE91

Enter /nSE91 in the SAP GUI command field.

1. In the Message Class field, enter your custom name (must start with Z or Y, e.g., Z_SALES_MSG).
2. Click Create.

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Step 2: Add Short Text and Attributes

1. In the Short Text field, enter a description (e.g., “Message Class for SD Sales Processing”).
2. Select a package (use $TMP for local testing or your project transport package).
3. Click Save.

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Step 3: Define Messages

Switch to the Messages tab.

Enter message numbers and their short text descriptions:

000  Invalid Sales Document Type: &1.
001  Customer &1 is credit blocked.
002  Delivery date cannot be in the past.
003  Sales Order &1 created successfully with &2 items.

Click Save. Your message class is now active and ready for use in any ABAP program.

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The 6 Message Types in ABAP

When you issue a message using the MESSAGE statement, you assign it a 1-character Message Type.

The message type determines how SAP reacts. Does it stop the program? Does it display a popup? Does it abort the transaction?

                    ┌──────────────────────────────┐
                    │      ABAP Message Types      │
                    └──────────────┬───────────────┘
                                   │
      ┌───────────┬────────────┬───┴──────────┬────────────┬───────────┐
      ▼           ▼            ▼              ▼            ▼           ▼
  ┌───────┐   ┌───────┐    ┌───────┐      ┌───────┐    ┌───────┐   ┌───────┐
  │ E (Error) │ A (Abort) │ W (Warning) │ I (Info) │ S (Status)│ X (Exit) │
  └───────┘   └───────┘    └───────┘      └───────┘    └───────┘   └───────┘

Here is how each type behaves:

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1. Error Message (Type ‘E’)

• Behavior: Interrupts processing. Displays the error message in red at the bottom status bar of the screen.
• Screen Reaction: In selection screens or classical screens, input fields are locked except for the fields where the error occurred. The user must correct the value and press Enter to re-try.
• Background Jobs: Causes the background job step to fail with an error log.

MESSAGE e001(z_sales_msg) WITH lv_kunnr.

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2. Abort / Termination Message (Type ‘A’)

• Behavior: Immediately terminates processing. Displays a popup dialog window with a stop icon.
• Database Reaction: Automatically triggers a database ROLLBACK WORK. All unsaved changes in the current transaction are discarded.
• Use Case: Fatal technical errors where continuing processing would corrupt data (e.g., database connection lost, critical configuration missing).

MESSAGE a002(z_sales_msg).

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3. Warning Message (Type ‘W’)

• Behavior: Displays a warning message in yellow at the bottom status bar.
• User Reaction: The user can acknowledge the warning by pressing Enter to bypass it and continue processing.
• Use Case: Non-fatal conditions (e.g., “Stock is low, but order can still be saved”).

MESSAGE w002(z_sales_msg).

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4. Information Message (Type ‘I’)

• Behavior: Displays a modal popup window containing the message text with an OK button.
• Processing: Once the user clicks OK (or presses Enter), processing continues automatically from the exact line where it paused.

MESSAGE i003(z_sales_msg) WITH lv_vbeln lv_item_count.

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5. Success / Status Message (Type ‘S’)

• Behavior: Displays a green success message at the bottom status bar on the next screen.
• Processing: Does NOT pause execution. Processing continues without interruption.

MESSAGE s003(z_sales_msg) WITH lv_vbeln lv_item_count.

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6. Exit / Short Dump Message (Type ‘X’)

• Behavior: Forces an immediate ABAP runtime error (Short Dump MESSAGE_TYPE_X).
• Use Case: Internal assertion failures that should never happen in production code.

MESSAGE x000(z_sales_msg).

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Message Type Behavior Matrix

Message Type	Status Bar Color	Pauses Program?	Triggers Rollback?	Can User Bypass?
S (Success)	Green	No	No	N/A
I (Information)	Popup Dialog	Pauses until OK	No	Yes (click OK)
W (Warning)	Yellow	Pauses input	No	Yes (press Enter)
E (Error)	Red	Stops screen flow	No	Must fix input
A (Abort)	Popup + Cancel	Terminates	Yes (Rollback)	No
X (Short Dump)	Crash Dump	Crashes program	Yes (Rollback)	No

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How to Syntax and Issue Messages in Code

ABAP offers several ways to write the MESSAGE statement depending on your setup.

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Method 1: Specifying Message Class at REPORT Level

If you declare your message class at the very top of your program, you don’t need to repeat the class name in every MESSAGE call.

REPORT z_sales_processing MESSAGE-ID z_sales_msg.

DATA: lv_kunnr TYPE kunnr VALUE '0000100045'.

" Uses message 001 from Z_SALES_MSG automatically
MESSAGE e001 WITH lv_kunnr.

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Method 2: Inline Message Class Declaration

You can specify the message type, number, and message class directly in a single string syntax:

DATA: lv_vbeln TYPE vbeln VALUE '0090000100',
      lv_count TYPE i VALUE 5.

" Syntax: MESSAGE <type><number>(<message_class>) WITH <var1> <var2> ...
MESSAGE s003(z_sales_msg) WITH lv_vbeln lv_count.

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Method 3: Dynamic Placeholders (WITH Addition)

You can pass up to 4 variables to fill placeholders &1, &2, &3, &4 inside a message text using the WITH keyword.

Suppose message 001 in class Z_MM is defined as:

Purchase Order &1 created for Vendor &2 in Plant &3.

In your ABAP program:

DATA: lv_ebeln TYPE ebeln VALUE '4500000123',
      lv_lifnr TYPE lifnr VALUE 'VEND_100',
      lv_werks TYPE werks_ext VALUE 'PL01'.

MESSAGE s001(z_mm) WITH lv_ebeln lv_lifnr lv_werks.

At runtime, SAP replaces &1 with 4500000123, &2 with VEND_100, and &3 with PL01.

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System Fields for Messages: SY-MSGID, SY-MSGNO, SY-MSGTY, SY-MSGV1

Whenever a MESSAGE statement executes, or whenever a BAPI/Function Module returns a message, SAP automatically populates four system variables in memory:

System Field	What it contains	Example Value
sy-msgid	Message Class ID	'Z_SALES_MSG'
sy-msgno	3-Digit Message Number	'001'
sy-msgty	Message Type (‘E’, ‘S’, ‘W’, etc.)	'E'
sy-msgv1	Content of 1st placeholder (&1)	'0000100045'
sy-msgv2	Content of 2nd placeholder (&2)	'PL01'
sy-msgv3	Content of 3rd placeholder (&3)	''
sy-msgv4	Content of 4th placeholder (&4)	''

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Raising Messages into System Fields without Displaying (INTO Addition)

Sometimes you want to format a message and capture its text inside a string variable without showing it on screen (e.g., when building an API log or writing to an error file).

Use MESSAGE ... INTO <variable>:

DATA: lv_formatted_text TYPE string.

MESSAGE e001(z_sales_msg) WITH '00100045' INTO lv_formatted_text.

" Program does NOT stop. The formatted string is saved in lv_formatted_text.
" System fields sy-msgid, sy-msgno, sy-msgv1 are also populated!
WRITE: / 'Captured Error:', lv_formatted_text.

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Message Handling in Function Modules and Exceptions

When calling function modules (via CALL FUNCTION), function modules can raise exception messages using RAISING or MESSAGE ... RAISING.

CALL FUNCTION 'Z_CALCULATE_TAX'
  EXPORTING
    im_amount             = lv_amount
  EXCEPTIONS
    invalid_amount        = 1
    tax_code_missing      = 2
    OTHERS                = 3.

IF sy-subrc <> 0.
  " Function module raised a message and set system fields sy-msgid, sy-msgno!
  MESSAGE ID sy-msgid TYPE 'E' NUMBER sy-msgno
          WITH sy-msgv1 sy-msgv2 sy-msgv3 sy-msgv4.
ENDIF.

This pattern catches the message emitted inside the function module and re-issues it cleanly in your main program.

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Quick Checkpoint — Test your understanding

Question 1: What is the difference between Message Type ‘E’ (Error) and Message Type ‘A’ (Abort)?

Answer: Type ‘E’ stops screen processing and forces the user to correct input on the screen. Type ‘A’ immediately terminates the program with a popup dialog and triggers an automatic database ROLLBACK WORK to undo all uncommitted changes.

Question 2: Which system fields store the message class name and message number after a message executes?

Answer: sy-msgid stores the Message Class name, and sy-msgno stores the 3-digit Message Number.

Question 3: How do you capture a message’s formatted text into a local string variable without displaying any notification to the user?

Answer: Use the INTO addition: MESSAGE e001(z_class) WITH var1 INTO lv_text.

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Common mistakes to avoid

Mistake 1: Hardcoding text strings directly in the MESSAGE statement. Writing MESSAGE 'Vendor does not exist' TYPE 'E'. is bad practice. Hardcoded text strings cannot be translated into other languages (German, French, Japanese) and lack central management. Always create a message class in SE91.

Mistake 2: Using Message Type ‘E’ inside background batch jobs without checking. In background jobs (SM37), an Error message (‘E’) terminates the current step. Make sure your background jobs handle errors gracefully using logs or custom return tables rather than crashing the job step unexpectedly.

Mistake 3: Forgetting that SY-MSGV1 to SY-MSGV4 are overwritten. Whenever ANY message executes in SAP, sy-msgv1 through sy-msgv4 get overwritten immediately. If you need those placeholder values later in your code, copy them to local variables immediately after the call.

" WRONG: Using sy-msgv1 several lines later after another function call
MESSAGE e001(z_msg) WITH '100'.
CALL FUNCTION 'SOMETHING_ELSE'. " <-- This overwrites sy-msgv1!
WRITE: sy-msgv1. " <-- Wrong value!

" RIGHT: Store immediately
MESSAGE e001(z_msg) WITH '100' INTO DATA(lv_dummy).
DATA(lv_saved_var1) = sy-msgv1.

Mistake 4: Not providing all 4 placeholders when re-issuing MESSAGE ID. When re-raising a captured message using MESSAGE ID sy-msgid TYPE sy-msgty NUMBER sy-msgno WITH sy-msgv1 sy-msgv2 sy-msgv3 sy-msgv4, always include all four placeholder variables. If you omit sy-msgv2, placeholder &2 will render as blank.

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Summary

Message handling is a core pillar of clean SAP development architecture.

By centralizing message texts in transaction SE91, using appropriate message types (E, A, W, I, S, X), and leveraging system fields (sy-msgid, sy-msgno, sy-msgv1), you build application programs that are multi-lingual, robust in background jobs, and easy to maintain across enterprise landscapes.

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Related reads on this site:

• SAP ABAP Debugging Guide — stepping through code and inspecting system fields
• Function Modules in ABAP — handling exceptions and importing/exporting parameters
• SAP ABAP IF-ELSE and CASE Statements — conditional evaluation before raising messages