Many Swiss SMEs run Bexio or Abacus and use only a fraction of what it offers. Writing invoices, reconciling the bank, a bit of bookkeeping. That works. What is often overlooked: both systems have open interfaces through which you can automate precisely the work that someone still does by hand today. Capturing receipts, copying data between programs, maintaining lists. This article sets out what the two systems can do out of the box, where the limit lies and what is actually achievable through the open interfaces.
What Bexio and Abacus can do out of the box
For smaller businesses, Bexio brings a solid base level of automation. The automatic payment reconciliation is the strongest part: as soon as a payment arrives in the bank account, Bexio marks the matching invoice as paid. For QR invoices, the system also automatically generates posting suggestions in the inbox. The mobile app scans photos of receipts via OCR and pre-fills fields.
An honest assessment matters here: for non-QR PDFs, the receipt lands in the inbox without supplier, date and amount filled in. Fully automatic posting recognition with contact matching, account and VAT assignment, and multi-stage approval sits in the higher Bexio packages. What lies below that is convenience, but not full automation.
Abacus plays in a different league. AI-supported document processing runs via the cloud components DeepBox (digital letterbox) and DeepO (the AI). Supplier invoices arrive by email, upload or scan; the AI reads out structured data, from the supplier address through VAT to individual invoice lines, assigns them to a cost centre or a project according to defined rules and automatically generates a posting along with an approval process. This is considerably closer to genuine straight-through processing.
Bexio or Abacus: a question of complexity, not headcount
The common rule of thumb is: Bexio for small businesses and start-ups, Abacus for mid-sized and larger structures. As a rough direction that holds true, but as the sole criterion it is misleading. What matters is not how many people you employ, but how complex your processes are.
| Criterion | More likely Bexio | More likely Abacus |
|---|---|---|
| Profile | start-ups, smaller SMEs | mid-sized, larger structures |
| Operation | lean, quick to get started | extensive, advisory-intensive |
| Payroll | simple | deeply integrated, demanding |
| Multiple entities / modules | limited | core strength |
| AI document processing | basic, package-dependent | DeepBox / DeepO, extensively developed |
| Interfaces | REST API | AbaConnect (XML/SOAP) plus REST modules |
A trading business with 40 employees and a simple structure can be perfectly happy with Bexio. A service provider with 15 people, but several companies, project-based billing and in-house payroll, will hit limits there more quickly. Before you consider switching, it is worth looking at whether your pain point really is the system, or merely a non-automated process within the system.
What the interfaces make additionally possible
This is the part most people leave unused. Neither system is a closed box.
Bexio offers a REST API. It works over HTTPS, uses JSON as its data format and is secured via OAuth2. Through the API you can read and write, among other things, contacts, invoices, quotations, orders, products, files and accounting data. You set up access in the Bexio developer portal. (A practical side note: anyone still using the old identity provider idp.bexio.com must migrate to auth.bexio.com; the old endpoint was switched off at the end of March 2025.)
Abacus offers several interfaces. Established is AbaConnect for XML import and export, and as a web service on a SOAP basis. Alongside this, Abacus is increasingly developing REST API modules. Together with AI processing via DeepBox, this gives a broad range of options for connecting Abacus to other systems.
What you can achieve with this can be thought of in three stages:
- Connecting without programming: platforms such as Zapier or Make link Bexio with other apps and automate simple trigger-action chains, for example “new order in the shop → create contact in Bexio”. Good for clearly defined, standardised processes.
- Data flows between systems: automatically reconcile master data, receipts or postings between your industry-specific system, online shop, CRM and accounting, without duplicate entry.
- Your own logic: recognise, check, enrich and post receipts according to your rules, where the ready-made building blocks fall short. This is the area in which a bespoke interface scores over standard connectors, because it is more robust, more traceable and designed around your exceptions.
Example flow: from email to receipt in Bexio
To make this concrete, here is a typical process as it can be implemented via the API. A supplier invoice arrives as a PDF in the mailbox. Without automation, what now happens is: download, open, read off the amounts, type them into Bexio, file the receipt. A few minutes per invoice, and over the course of a year that adds up.
Automated, the same path looks like this:
- Receipt. The invoice lands in a defined mailbox or folder.
- Recognition. An AI-supported document recognition reads out supplier, date, amount, VAT and invoice number, including from non-QR PDFs.
- Checking and assignment. The data is matched against your supplier list, account and VAT code are assigned according to your rules, anomalies are flagged.
- Handover. Via the Bexio API, the receipt is created along with structured data and PDF attachment, in the appropriate status.
- Approval. Disputed cases go to a person, the rest runs through.
The decisive point is steps 3 and 5. No one with any sense hands financial postings over blindly to a machine. A serious automation recognises its own uncertainty and presents doubtful cases to a person, rather than hiding them. It is precisely this pattern, AI for the legwork, the human for the decision, that we operate at Vollmer Labs in the form of accounting agents in a production setup at a US fiduciary client. The building blocks for this are proven; for Swiss Bexio installations we adapt them to the respective account assignment and approval logic.
What you must not overlook regarding retention
Automated receipt flows touch on the statutory retention obligation, and that applies regardless of whether you work on paper or digitally. The following points are to be understood as legal facts, not as a technical recommendation:
- Under Art. 958f of the Code of Obligations (CO), accounting records and accounting vouchers, as well as business and audit reports, must be retained for ten years. The period begins at the end of the financial year.
- The Ordinance on the Keeping and Preservation of Books of Account (GeBüV) governs the permissible information carriers. Electronic retention is permitted, provided that integrity (no alterability, manipulation detectable) and availability (legible at all times and capable of being restored in an orderly manner) are ensured.
- For alterable data carriers, the GeBüV requires additional measures such as combined integrity protection and timestamps, so that the retention is regarded as legally compliant.
- The GeBüV in the version of 1 January 2013 remains authoritative. A revision called for by Parliament to ease digital archiving for SMEs has been initiated via the motion “Make digital bookkeeping easier” (adopted in the National Council in 2022), but has not yet entered into force as a revised ordinance.
In practice, for your automation this means: the original PDF must be filed in an audit-proof manner and remain legible for ten years. A receipt that hangs in Bexio as an image, while the original only sat in the mailbox that is emptied after a year, does not reliably meet this requirement. Anyone building receipt flows must factor in the filing from the outset, not after the fact.
If you can cleanly answer these three questions for your business, you are on a good path: which step eats up the most manual time today? Does my system provide a ready-made function for it, a standard connector, or does it need its own interface? And where do the receipts remain stored in a legally compliant way for ten years?