IBANTools-Germany: Validator and Generator for German Bank Accounts

This TypeScript/JavaScript library validates IBAN and German bank account numbers. It can be used standalone or as an enhancement of IBAN validators, like IBANTools.

If you need German bank data in your project, e.g., to auto-fill forms when a user enters an IBAN, take a look at the side project BankData-Germany.

Version 1.2403.* includes data from 2024-09-09 to 2024-12-08, as well as from 2024-12-09 to 2025-03-02. Validation will be based on the data that is valid according to your system time (data changes at midnight CET on 2024-12-09).

• Installation
• Usage
• Data Source
• Package Version

Installation

Package Manager

Add it to your project using a package manager like npm or yarn. You should explicitly install the latest version, as the bank data may change multiple times a year.

1$ npm install --save ibantools-germany@latest
2# or
3$ yarn add ibantools-germany@latest

Browser / CDN

If you only want the functions in your browser, you can include the following pre-built file.

1<script src="https://cdn.jsdelivr.net/npm/ibantools-germany/dist/build/browser.js"></script>

Usage

The npm package contains the code for both ESM and CJS. Therefore, in addition to using import as shown in the usage examples below, you can also utilize require.

Validation

You can validate the bank account number and BLZ (Bankleitzahl = bank sort code), a BBAN, or an IBAN. Additionally, you have the option to restrict IBAN validation to only allow German IBANs.

1import { isValidAccountNumberBLZ, isValidBBAN, isValidIBAN } from "ibantools-germany"
2
3isValidAccountNumberBLZ("9290701", "10220500"); // true
4
5isValidBBAN("102205000009290701"); // true
6isValidBBAN("20041010050500013M02606"); // false (valid but not a German BBAN)
7
8isValidIBAN("DE23102205000009290701"); // true
9isValidIBAN("FR1420041010050500013M02606"); // true
10isValidIBAN("FR1420041010050500013M02606", false); // false (only allow German IBAN)

Generation

1import { generateBBAN, generateIBAN } from "ibantools-germany"
2
3generateBBAN("9290701", "10220500"); // 102205000009290701
4generateBBAN("foo", "bar"); // null
5
6generateIBAN("9290701", "10220500"); // DE23102205000009290701
7generateIBAN("foo", "bar"); // null

Browser / CDN

When using the pre-built version, the ibantoolsGermany object is globally defined on the window, containing the functions.

1ibantoolsGermany.generateBBAN("9290701", "10220500");
2ibantoolsGermany.generateIBAN("9290701", "10220500");
3ibantoolsGermany.isValidAccountNumberBLZ("9290701", "10220500");
4ibantoolsGermany.isValidBBAN("102205000009290701");
5ibantoolsGermany.isValidIBAN("DE23102205000009290701");

Data Source

Unfortunately, there isn't a single algorithm to verify all German bank account numbers or BBANs, as each bank employs its own method(s) which can change periodically. To address this, Deutsche Bundesbank publishes updated data every quarter.

These updates can encompass both technical changes, such as modifications in check digit methods, as well as content changes like alterations to BLZ, bank names, and more. Some updates might not contain any relevant changes for this library at all.

Package Version

The version numbers are based on Semantic Versioning with some modifications.

1.2205.3

The first number represents the Major version. If this number increases, there may be updates that are not backward compatible, requiring adjustments to your code. In the above version string, the major version is 1.

The first two digits of the second number indicate the year of the included data and check digit methods. The third and fourth digits increase either with minor version changes that maintain backward compatibility or when new data is included. In the provided version string, the year is 2022, with a few minor updates, possibly including data updates for spring and summer.

The last number is reserved for patches and bug fixes.

Considering that the data could change up to four times a year, it's advisable to use an appropriate version string in your package.json. As breaking changes occur only when the first number changes, specifying something like "1.x" should suffice.