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BuchhaltungsButler is a cloud accounting automation platform widely used by SMEs and accounting firms in Germany and Austria. It focuses on receipt capture, automated booking, and tax reporting, with native support for German chart of accounts standards SKR03 and SKR04. The API is available from the Buchhaltung Pro plan onwards.
Integrate BuchhaltungsButler alongside dozens of other accounting and ERP systems through Maesn Unified API.
Basic Auth Without OAuth: Per-Tenant Credential Storage Gone
BuchhaltungsButler authenticates via HTTP Basic Auth using a per-account API Client and API Secret, with no OAuth flow or automated token exchange. For multi-tenant SaaS products, this means collecting, encrypting, and managing credentials per customer yourself.
Maesn wraps this entirely: your customers connect once through a standard auth flow, and you never store raw credentials yourself.
SKR03 and SKR04: Tenant-Specific Account Codes Resolved Automatically
BuchhaltungsButler uses SKR03 and SKR04 as its primary chart of accounts structures. Posting entries or receipts requires correct account codes that vary per tenant and per chart of accounts version.
Maesn resolves the correct account codes per tenant automatically during onboarding. Your code never touches raw SKR lookups or conditional account mapping logic.
API on Paid Plan Only: No Surprise Failures Mid-Onboarding
The BuchhaltungsButler API is only available on the Buchhaltung Pro plan. Free plan and lower-tier customers cannot connect via API.
Maesn's onboarding documentation makes this requirement clear upfront, so your customers are guided correctly from the start.
"Adding Qonto to our existing integrations was a piece of cake with Maesn. It is a game changer for our customers with all the integration cababilites!"
Juri Preis
CEO @ Smarta
Learn more about BuchhaltungsButler API Integration
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Why companies choose Maesn
3 Reasons Why It Is Better To Integrate BuchhaltungsButler API With Maesn
Secure & Compliant
We have a strong relationship to BuchhaltungsButler. This ensures that the Maesn API is always up-to-date and any maintenance is covered on our end.
Common Data Model
We provide a clean, unified data model that abstracts away system-specific quirks, so teams can build reliable integrations without dealing with ERP-specific complexity or workaround-heavy implementations.
BuchhaltungsButler Sandbox
We provide you with everything you need, so you can focus on what counts.
BuchhaltungsButler is a cloud accounting automation platform for SMEs and accounting firms in Germany and Austria. It focuses on receipt capture, automated booking, and tax reporting. The API covers receipts, transactions, invoices, postings, and account management, and is available from the Buchhaltung Pro plan.
The main challenges are managing HTTP Basic Auth credentials per tenant without an OAuth flow, mapping German chart of accounts structures (SKR03 and SKR04) per tenant before posting transactions, handling the plan restriction that limits API access to Buchhaltung Pro users, and ensuring German GoBD compliance in how documents and postings are structured.
BuchhaltungsButler uses HTTP Basic Auth with a per-account API Client and API Secret rather than OAuth 2.0. This simplifies single-tenant setups but requires multi-tenant SaaS products to collect, store, and manage credentials per customer without an automated authorization flow.
SKR03 and SKR04 are the two standard German charts of accounts. SKR03 is used primarily by service companies; SKR04 is used primarily by industrial companies. In BuchhaltungsButler, all posting entries reference account codes from the tenant's configured chart of accounts. Using the wrong account code produces incorrect bookings. Maesn handles this mapping per tenant automatically.
A direct integration requires managing Basic Auth credentials per tenant, mapping SKR03 or SKR04 account codes per customer, handling plan restrictions in your onboarding flow, and understanding German GoBD document requirements. Maesn handles all of this through a single unified API.
Frequently Asked Questions About BuchhaltungsButler Integration
