OpenIBAN vs BankCheck

Overview

OpenIBAN is a free, open-source IBAN validation service released under the Apache 2.0 license and written in Go. As of March 2026, OpenIBAN has been active for approximately eight years and attracts around 40K monthly visitors. The project is community-driven and built with privacy in mind — it performs no tracking, no logging, and processes all data in memory only. OpenIBAN is completely free with no rate limits, and it can be self-hosted by anyone who wants to run their own validation instance. The service provides enhanced validation (including bank name lookup and checksum verification) for seven countries: Germany, Austria, Switzerland, Belgium, the Netherlands, Czech Republic, and Liechtenstein. For all other IBAN countries, it offers basic structural validation only. OpenIBAN does not support US routing numbers, UK sort codes, SWIFT/BIC codes, or IBAN calculation.

BankCheck is a dedicated bank number validation tool that supports IBANs across 80+ countries, US routing numbers, UK sort codes, and SWIFT/BIC codes. All validation runs client-side in the browser — no data is sent to any server. BankCheck requires no signup, offers a free public REST API with no API key, and includes 890+ bank records across 41 IBAN countries. Where OpenIBAN is a lightweight open-source API for IBAN validation with deep support for a handful of European countries, BankCheck is a broader validation platform covering multiple bank number formats with a full web interface.

Feature Comparison

Where OpenIBAN Excels

OpenIBAN's standout quality is that it is fully open source. The entire codebase is available under the Apache 2.0 license, meaning anyone can audit the validation logic, fork the project, or contribute improvements. For organizations with strict vendor requirements or teams that need to understand exactly how validation works at the code level, this transparency is invaluable. No other major IBAN validation service offers the same level of source code access.

Self-hosting is a direct consequence of being open source, and it is a significant advantage for specific use cases. Companies that cannot send bank data to any external service — whether due to regulatory constraints, internal security policies, or air-gapped infrastructure — can deploy OpenIBAN on their own servers and validate IBANs entirely within their own network. The Go-based architecture is lightweight and efficient, making it straightforward to run as a microservice alongside existing payment infrastructure.

OpenIBAN is also genuinely free with no strings attached. There are no rate limits, no usage tiers, no freemium upsells, and no account requirements. For hobbyist projects, small businesses, or developers experimenting with IBAN validation, the complete absence of commercial friction is refreshing. The project's commitment to privacy — no tracking, no logging, memory-only processing — reflects a principled approach to handling sensitive financial data on the server side.

Where BankCheck Differs

BankCheck's most fundamental difference is client-side validation. While OpenIBAN processes IBANs on a server (even if it does so responsibly with no logging), BankCheck's validation engine runs entirely in your browser. When you check an IBAN on BankCheck, no network request is made at all — the bank number never leaves your device. This is a stronger privacy guarantee than "we don't log it" because the data simply never reaches a server in the first place.

Coverage is another major differentiator. OpenIBAN provides enhanced validation for only seven European countries, with basic structural checks for the rest. BankCheck offers bank data enrichment across 41 IBAN countries with 890+ bank records, and goes well beyond IBANs entirely. You can validate US routing numbers, UK sort codes, and SWIFT/BIC codes in the same interface, with automatic format detection. For teams that handle international payments across different standards, this multi-format support eliminates the need to cobble together separate tools.

BankCheck also provides a full web interface alongside its API. OpenIBAN is primarily an API service — while it has a minimal web page, the product is designed for programmatic use. BankCheck serves both developers (via its free REST API) and non-technical users (via its web app) equally well, with guides, a glossary, transfer corridor information, and an IBAN generator available alongside the core validation tool.

Bottom Line

OpenIBAN and BankCheck are both free, privacy-conscious validation tools, but they make different trade-offs. OpenIBAN is the right choice if you need open-source code you can audit and self-host, particularly if your validation needs are focused on German-speaking and Benelux IBANs where OpenIBAN has deep support. Its Apache 2.0 license and zero-logging architecture make it uniquely suited for on-premises deployment in regulated environments.

BankCheck is the stronger option when you need broader format coverage (IBANs across 80+ countries plus US, UK, and SWIFT formats), client-side validation that keeps data entirely in the browser, or a web interface that non-developers can use. The two tools can work together well — teams might self-host OpenIBAN for internal pipeline validation while using BankCheck for manual checks and formats that OpenIBAN does not support.