maesn

maesn is a unified API for accounting and ERP systems. A software company integrates once and reaches more than 30 European systems through normalised data models, a single authentication flow, real-time webhooks and shared logging, instead of building and maintaining a separate connector for each one. The company emphasises depth as well as breadth, arguing that a unified API is only useful if it exposes the fields customers actually need rather than a lowest common denominator across systems.

Why it is in a partner tech directory

The same reason as the other tools in this category. Technology partnerships stall at the integration, and a partnerships team that has agreed to connect with a dozen accounting systems needs those connectors to exist. Unified APIs remove that engineering dependency, which makes them partner infrastructure even though the buyer is usually a product or engineering leader.

What separates it from other unified APIs

Geography, which in this market is the whole argument. The well-known unified accounting APIs are built primarily around QuickBooks, Xero and NetSuite and treat the European long tail as an afterthought. maesn is built the other way round, covering systems such as DATEV, Lexware, Sage, Exact Online and Microsoft Dynamics 365 Business Central. DATEV in particular is close to unavoidable for German SMB accounting and is not well served by the global vendors, so for a software company selling into Germany or the wider DACH region this is often less a preference than the only practical route.

That focus comes with the corresponding limitation. A company whose customers are mostly on North American systems will find the coverage mismatched, and should look at the global unified API vendors instead.

The compliance position reinforces the same point. The company states that the product is built and hosted in Germany and holds ISO certification alongside GDPR compliance, which matters to exactly the buyers its coverage targets.

Who it fits

Software companies selling into Germany, Austria, Switzerland and the wider European market that need accounting or ERP integrations, and whose customers run local systems rather than the global ones.

Ownership and company background

Founded in 2022 and based in Düsseldorf, Germany. No funding rounds could be confirmed from a credible source in this pass. The company published content regularly through mid-2026, so the product is actively maintained.

Pricing

The company maintains a pricing page describing a structure that scales with usage, but figures were not captured in this review. Check the page directly rather than relying on a quoted rate.

Integrations

More than 30 European accounting and ERP systems, including DATEV, Lexware, Sage, Exact Online and Microsoft Dynamics 365 Business Central. SDKs are offered across several programming languages.