erpl-pyrfc — a drop-in PyRFC replacement for SAP RFC in Python, with no SAP NW RFC SDK

This repository is the public issue tracker for erpl-pyrfc. The source is not public; the bug tracker is. Open an issue →

pip install erpl-pyrfc

import pyrfc  # the same import, unchanged

conn = pyrfc.Connection(ashost="…", sysnr="00", client="001", user="…", passwd="…")
print(conn.call("STFC_CONNECTION", REQUTEXT="hello")["ECHOTEXT"])

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Why this exists

SAP archived PyRFC in 2024. The wheels were yanked, the repository is read-only, and the last release does not build against current Python. Anyone still calling SAP RFC from Python was left with three bad options: pin an old Python, build a C extension against the SAP NW RFC SDK by hand, or rewrite.

erpl-pyrfc is the fourth option. It claims the pyrfc import namespace and implements the RFC protocol in pure Rust, so the SDK is not needed at all.

	SAP PyRFC 3.3.1	erpl-pyrfc
SAP NW RFC SDK required	yes — S-user download, manual install	no
ICU 50 shared libraries	yes	no
Install	build from source	pip install, prebuilt wheels
Python	≤ 3.12 in practice	3.9 – 3.13+
Platforms	whatever you build	manylinux · musllinux · macOS (x86-64, arm64) · Windows
Maintained	archived 2024	actively developed
import pyrfc	✔	✔ same namespace

No SAP S-user account, no nwrfcsdk tarball, no LD_LIBRARY_PATH, no ICU. One wheel, one pip install.

What works

Everything the archived library did, verified by running the same script under both and diffing the output:

• Client calls — call(), typed and untyped, structures, tables, deep and nested structures
• All ABAP scalar types — including DECFLOAT16/34, INT8, UTCLONG, packed decimals at full precision
• Server mode — register as an RFC destination and receive calls from ABAP
• tRFC and qRFC — transactional and queued units of work
• SNC — Secure Network Communications, snc_qop 1–9
• Throughput — the same seven stats keys, attach/detach, monitors summing several connections
• basXML — SAP's binary serialization, chosen per function module by the server, handled transparently
• Connection pooling, cancellation, error taxonomy and codes

Two things go beyond PyRFC:

• wsRFC — RFC over a WebSocket with X.509 client-certificate sign-on
• mshost_override — for a message server that reports an address only resolvable inside its own network

Deliberately absent: bgRFC background units. Everything else PyRFC exposed is here, including the module-level surface (cancel_connection, RfcFieldType, RfcParameterDirection, RCStatus, UnitState, UnitCallType, TypeDescription, FunctionDescription, ConnectionParameters, language_iso_to_sap, …).

How it is built

The protocol was reverse-engineered clean-room, from packet captures of SAP's own library talking to a real ABAP system — never by reading another implementation's source. Every rule in the specification is evidenced by a capture, and every capture is committed next to the rule it proves.

Read the story:

• A drop-in replacement for the archived PyRFC — what broke, and the migration
• The SAP RFC protocol, byte by byte — NI framing, APPC, the RFC_PRO field sequence
• SAP RFC over WebSockets — wsRFC and certificate sign-on
• Faster SAP ingest without the SDK
• 10M BSEG rows a minute

Reporting a bug

Open an issue here. What helps most:

1. The function module and its interface — RFC_GET_FUNCTION_INTERFACE output, or the SE37 screenshot
2. A minimal script that reproduces it
3. Versions — pyrfc.__version__, Python, OS, and the SAP kernel release
4. What SAP PyRFC did, if you can still run it — a behavioural difference is the most actionable report there is

Please do not paste credentials, hostnames or business data. A redacted trace is worth more than none.

Other SAP tooling from DataZoo

erpl-pyrfc is one piece of a wider set of SAP integration tools:

Project	What it does
erpl	DuckDB extension connecting SAP RFC, ODP and BW to your analytics stack
erpl-web	DuckDB extension for OData, GraphQL and REST — SAP ERP, Ariba, C4C, Dynamics
erpl-rev	SAP RFC server bridging ABAP into DuckDB — the inverse direction
erpl-adt	CLI and MCP server for the SAP ADT REST API — no Eclipse, no JVM
erpl-tunnel	Tunnel SAP RFC and HTTP over SSH, Tailscale or NetBird
flapi	Build APIs on DuckDB for data apps and AI agents

More at erpl.io.

Let's talk

Building on SAP RFC, migrating off PyRFC, or solving this differently? I would genuinely like to compare notes — especially on how people test SAP integrations without a spare system to break.

Connect with me on LinkedIn →

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