IBAN Validation for Polars (iban_validation_polars)

A high-performance Polars plugin for validating IBANs (International Bank Account Numbers) and extracting bank/branch identifiers leveraging Polars Multi-threaded feature and performance.

Quick Start

Example:

import polars as pl
from iban_validation_polars import process_ibans
import os

inputfile = r'iban_validation_rs/data/IBAN Examples.txt'
outputfile = r'iban_validation_polars/examples/test_file.csv'

# File generation 
df = pl.read_csv(inputfile).sample(10000000, with_replacement=True)
df.write_csv(outputfile)
print('writing to file complete')

# using the library
df = pl.scan_csv(outputfile)\
    .with_columns(
    validated=process_ibans('IBAN Examples').str.split_exact(',',2)\
        .struct.rename_fields(['valid_ibans', 'bank_id', 'branch_id'])
).unnest('validated').sort(by='IBAN Examples', descending=True)

# show some results
print(df.collect(streaming=True))

# cleanup
os.remove(outputfile)

Features

✅ Fast IBAN validation (Rust-powered)

✅ Bank identifier extraction

✅ Branch identifier extraction

✅ Support for all IBAN countries (SWIFT Registry v99)

✅ Zero-copy operations where possible

Installation

pip install iban-validation-polars

Performance Benchmarks

This polars plugin was the principal objective of this library; the benchmarks here highlight how much faster it is to use the plugin than to call the Python library with map_element (about 100 times faster).

API Reference

process_ibans(column: pl.Expr) -> pl.Expr Validates IBANs and extracts bank/branch information in a single operation. Parameters:

• column: A Polars expression containing IBAN strings in electronic format (no spaces) Electronic format only: No spaces or special characters. Case insensitive: Both uppercase and lowercase accepted when the IBAN definition allows it. Length: 15-34 characters depending on country, as per the registry definition.

Returns:

• pl.Expr: A struct expression containing:
  • validated_iban (str): The valid IBAN if validation passes, empty string if invalid
  • bank_code (str): Bank identifier code (when relevant and valid) otherwise empty
  • branch_code (str): Branch identifier code (when relevant and valid) otherwise empty

Non-registry countries

By default, only the official SWIFT IBAN registry countries validate. Pass allow_non_registry=True to process_ibans to additionally accept 22 IBAN-shaped account numbers that are not in the official registry (community-sourced, weaker guarantees):

df.with_columns(
    validated=process_ibans("ibans", allow_non_registry=True)
    .str.split_exact(",", 2)
    .struct.rename_fields(["valid_ibans", "bank_id", "branch_id"])
).unnest("validated")

allow_non_registry defaults to False, so existing pipelines are unaffected.

Use country_status(column: pl.Expr) -> pl.Expr to classify each IBAN as "registry", "non_registry", or "invalid" without needing to decide allow_non_registry up front - filter or group on the result in pure Polars:

from iban_validation_polars import country_status

df.with_columns(status=country_status("ibans"))

Common Use cases

• Data Cleaning pipeline (see pandera_example.md)
• Data validation report
• Extracting valid IBANs only (filter for non-empty valid IBANs)

Error Handling

This pluging does not raise exception under normal operation.

Credits

Cheers to the pyo3-polars project! It made this library possible.

Changes

• 0.1.30: updated to registry version 103 (a change to Brazil IBAN definition). rust updated to 1.99.0.
• 0.1.29: added opt-in allow_non_registry keyword argument (default False) to process_ibans, plus a new country_status expression classifying IBANs as "registry" / "non_registry" / "invalid".
• 0.1.28: upgraded to polars 0.54.4, rust 1.96.1, update to iban registry version 102 from Jun 2026 (no significant changes for this package)
• 0.1.26: added user_friendly iban validation (handle spaces), added compile time checks, and updated to rust 1.93, dropping python 3.9, adding python 3.14
• 0.1.25: added forbidden checksums in the validation
• 0.1.24: update to the python interface only
• 0.1.23: upgraded to latest Iban register (version 101), only change Portugal (no branch anymore). updated to rust 1.92.0.
• 0.1.22: upgraded to latest Iban register (version 100), only Albania (AL) and Poland (PL) have changes affecting this project. updated to rust 1.91.1.
• 0.1.21: upgraded to polars 0.52.0, rust 1.91, improved internal data structure. Enable modern CPU instruction on x86 (x86-64-v3) and Mac (M1) for python, polars and c packages.
• 0.1.20: technical update upgraded to polars 0.51.0, rust 1.90
• 0.1.19: technical update upgraded to polars 0.50.0, rust 1.89. Improved Polars documentation.
• 0.1.18: technical update upgraded to polars 0.49.1, pyo3 0.25, rust 1.88
• 0.1.17: memory usage reduced.
• 0.1.16: improved performance, added territories for GB and FR, and more tests, added WASM (experimental for now), added fuzzer.
• 0.1.15: improved performance (char to bytes) and improved c wrapper doc.
• 0.1.13: technical update to polars 0.48.1 and pyo3 0.24.
• 0.1.11: eliminated rust dependencies (rust code generated from Python instead of Hash and Serde).
• 0.1.9: improve mod97 perf (reduce memory needed).
• 0.1.8: improve mod97 perf (cpu memory tradeoff).
• 0.1.7: improve performance related to the Iban structure again.
• 0.1.6: improve performance related to the Iban structure.
• 0.1.5: add support for Python 3.13.
• 0.1.4: technical update; updated polars dependency to polars 0.46.0, pyo3-polars 0.20, and py03 0.23.