Two of the most common techniques for moving data in and out of SAP are BAPI and BDC. They solve similar problems — getting data into SAP or triggering SAP processes from outside — but they work in fundamentally different ways.
If you are learning ABAP or preparing for an interview, understanding the difference between BAPI and BDC is essential. This guide explains both, compares them side by side, and tells you when to use each.
What Is a BAPI?
BAPI stands for Business Application Programming Interface. A BAPI is a standardized, stable method for accessing SAP business objects and processes from external programs or other SAP systems.
Key characteristics of BAPIs:
- Object-oriented design — BAPIs are methods of SAP business objects (like Material, Sales Order, or Purchase Order).
- Stable interfaces — SAP guarantees that BAPI interfaces remain stable across releases, so programs built on them do not break after upgrades.
- Remote-enabled — BAPIs are RFC-enabled function modules, meaning they can be called from external systems (Java, .NET, web services) as well as from ABAP.
- Business logic included — When you call a BAPI, all of SAP’s built-in validations, checks, and business logic run automatically — just as if a user had done the transaction manually.
- Transaction control — BAPIs generally do not commit data themselves; the calling program must issue an explicit
BAPI_TRANSACTION_COMMITto save changes.
A classic example is BAPI_MATERIAL_SAVEDATA, which creates or changes material master data, or BAPI_SALESORDER_CREATEFROMDAT2, which creates a sales order. You pass structured data in, SAP validates it, and you get a return table with messages.
Simple BAPI Call Example
DATA: lt_return TYPE TABLE OF bapiret2.
CALL FUNCTION 'BAPI_MATERIAL_SAVEDATA'
EXPORTING
headdata = ls_headdata
TABLES
return = lt_return.
CALL FUNCTION 'BAPI_TRANSACTION_COMMIT'
EXPORTING
wait = 'X'.The pattern is always similar: call the BAPI, check the return messages for errors, then commit.
What Is BDC?
BDC stands for Batch Data Communication (also called Batch Input). It is SAP’s classic technique for transferring data into the system by simulating user input on screens — essentially replaying the keystrokes and field entries a user would make in a transaction.
BDC works in two ways:
1. Session Method (Batch Input Session)
- Data is collected into a batch input session (a queue) using
BDC_OPEN_GROUP,BDC_INSERT, andBDC_CLOSE_GROUP. - The session is then processed later via transaction SM35, either in the foreground, background, or with error handling.
- Sessions can be reprocessed if errors occur, and detailed logs are kept.
2. Call Transaction Method
- The ABAP program builds a BDCDATA table describing the screens and field values, then calls the transaction directly with
CALL TRANSACTION ... USING bdcdata. - Processing happens immediately in the program run — no SM35 session involved.
- Faster and simpler, but error handling is the program’s own responsibility.
Simple CALL TRANSACTION Example
DATA: lt_bdcdata TYPE TABLE OF bdcdata,
ls_bdcdata TYPE bdcdata.
ls_bdcdata-program = 'SAPMM07M'.
ls_bdcdata-dynpro = '0400'.
ls_bdcdata-dynbegin = 'X'.
APPEND ls_bdcdata TO lt_bdcdata.
ls_bdcdata-fnam = 'MSEG-WERKS'.
ls_bdcdata-fval = '1000'.
APPEND ls_bdcdata TO lt_bdcdata.
CALL TRANSACTION 'MIGO' USING lt_bdcdata MODE 'N'.This mimics a user opening the transaction and typing values into fields.
BAPI vs BDC: Comparison Table
| Aspect | BAPI | BDC |
|---|---|---|
| Approach | Calls a stable API method | Simulates screen input |
| Speed | Fast (direct processing) | Slower (screen-by-screen) |
| Upgrade safety | Very safe — interfaces are stable | Risky — breaks if screens change |
| Error handling | Structured return messages | Screen messages, harder to parse |
| External system access | Yes — RFC-enabled | No — ABAP only |
| Business logic | Full SAP validations run | Full SAP validations run (via screens) |
| Background processing | Easy | Session method supports it via SM35 |
| Availability | Only where SAP provides a BAPI | Works for almost any transaction |
| Learning curve | Moderate (know the BAPI’s parameters) | Steeper (record screens with SHDB) |
When to Use Which
Use BAPI when:
- A BAPI exists for the business object you need (check transaction BAPI or the BAPI Explorer).
- You are integrating an external system (the RFC capability is the deciding factor).
- You want upgrade-safe, maintainable code.
- Performance matters — BAPIs skip the screen layer entirely.
Use BDC when:
- No BAPI or standard function module exists for the transaction.
- You need to replicate an exact user process, including custom screens or user exits tied to screens.
- You are doing a one-time data migration where speed of development matters more than elegance.
- You want the SM35 session’s reprocessing and logging features for error-prone loads.
The general rule of thumb: BAPI first, BDC as the fallback. Modern SAP development also favors other options where available — such as IDocs for EDI-style integration or OData services for Fiori apps — but between these two classic techniques, BAPI is almost always the preferred choice when it exists.
How BDC Recordings Are Created
A practical note for beginners: BDC programs are usually built by recording the transaction first. Transaction SHDB lets you record the screens, fields, and values of a manual transaction run, and then generates the BDCDATA skeleton code for you. You then generalize that code — replacing hardcoded values with variables and looping over your input data.
A Practical Decision Walkthrough
Imagine you need to load 10,000 vendor master records from a legacy system into SAP. How do you choose?
Step 1 — Check for a BAPI. Search the BAPI Explorer (transaction BAPI) for the vendor business object. If a suitable BAPI exists, use it: write an ABAP program that reads your input file, maps each record to the BAPI’s parameters, calls the BAPI in a loop, collects return messages, and commits in packages (for example, every 500 records). This gives you the fastest, most upgrade-safe load.
Step 2 — If no BAPI exists, consider an IDoc or standard migration tool. For master data especially, SAP often provides standard IDoc message types or migration objects that are more robust than screen-based loading.
Step 3 — Fall back to BDC. Record the vendor creation transaction with SHDB, generate the BDCDATA skeleton, and generalize it into a loop over your input file. Use the session method if you want SM35’s logging and reprocessing for a large, error-prone load; use CALL TRANSACTION if you want immediate inline processing and simpler code.
This decision order — BAPI, then standard tools, then BDC — is exactly what experienced interviewers want to hear, because it shows you understand not just the mechanics but the engineering trade-offs.
Frequently Asked Questions
Q1. What is the full form of BAPI and BDC?
BAPI stands for Business Application Programming Interface. BDC stands for Batch Data Communication (also referred to as Batch Input).
Q2. Which is faster, BAPI or BDC?
BAPI is faster because it processes data directly without going through the screen layer. BDC simulates screen-by-screen user input, which adds overhead.
Q3. Can BAPIs be called from non-SAP systems?
Yes. BAPIs are RFC-enabled function modules, so external systems built in Java, .NET, Python, or other languages can call them remotely.
Q4. What is the difference between the BDC session method and CALL TRANSACTION?
The session method stores data in a batch input session processed later via SM35, with built-in logging and reprocessing. CALL TRANSACTION processes the data immediately within the program, which is faster but leaves error handling to the developer.
Q5. Do BAPIs commit data automatically?
No. Most BAPIs do not issue a database commit themselves. The calling program must call BAPI_TRANSACTION_COMMIT after verifying the return messages, or BAPI_TRANSACTION_ROLLBACK if something failed.
Q6. Is BDC still relevant in S/4HANA?
BDC still works, but SAP’s direction favors APIs, OData services, and migration tools. For new developments, check whether a BAPI, OData service, or standard migration object exists before building a BDC.
The Bottom Line
BAPI and BDC are both data-transfer techniques, but they belong to different eras of thinking. BAPI is the clean, stable, API-based approach — fast, upgrade-safe, and callable from anywhere. BDC is the screen-simulation workhorse — slower and more fragile, but able to handle any transaction, including ones with no API.
Learn both, prefer BAPI, and keep BDC in your toolkit for the cases where nothing else fits.
Working with materials data in your BAPI or BDC programs? Our SAP MM tables complete list shows you exactly where material master data lives.