INTEROPERABILITY

What Swiss software can really exchange, vendor by vendor

They all announce an interface. Few say what it contains, and none says what it does not do.

We read the technical documentation of eleven management suites used by Swiss SMEs, on 23 August 2026, and recorded one thing only: what a third party can really get out of them. Here is the table, with its sources. It is worth what the vendors' documentation is worth, it can be checked line by line, and it changes everything when the time comes to choose.

What the survey shows

Swiss compliance is acquired. The QR-bill is present everywhere, eight suites out of eleven appear in the Swissdec register with their certificate number. The ground gives way elsewhere. Only one suite documents webhooks, only one is itself a Peppol access point, and two do not open their interface to non-partners.

SURVEY OF 23.08.2026 IN THE ELEVEN VENDORS' DOCUMENTATION

These figures do not say a piece of software is bad. They say where the work moves. A vendor that publishes no webhook has made an architecture choice, and that choice arrives at your door as a gateway polling in a loop, slower and more costly to keep alive.

Eleven suites, nine columns

Each cell comes from the vendor's documentation, read on 23 August 2026. When the vendor publishes nothing on a point, the cell says not documented, never absent, because absence of proof is not proof of absence.

Interfaces and compliance of eleven management suites used in Switzerland, surveyed in the vendors' documentation on 23 August 2026
Software	Interface for a third party	Type of interface	Webhooks	Access to the key	QR-bill	eBill	Peppol	Swissdec
AbacusAbacus Research AG	yes	REST OAuth 2.0, and AbaConnect in batches	not documented	via a certified partner	yes	yes, SIX network partner	via Descartes STEPcom	certified plus, ELM 5.5
bexiobexio AG, Mobilière group	yes	REST 2.0, OAuth 2.0, personal token	not documented	open	yes	via a Marketplace app	not on the OpenPeppol list	certified, ELM 5.0 to 5.3
Banana Comptabilité PlusBanana.ch SA	partial	local server, read only	not documented	Advanced plan only	yes	announced as not available	not documented	not certified
CrésusEpsitec SA	no public API	text files, CSV, ISO 20022	no	not applicable	yes	yes, for issuing	no published mention	certified basic, ELM 5.0
Infoniqa ONE 50 and ONE 200Infoniqa Schweiz AG, formerly Sage Switzerland	yes	REST JSON, installed at the client's	not documented	open, unassisted installation	yes	documented on the ONE 200 side	absent from the directory	certified basic, ELM 5.0
KLARAePost Service AG, Swiss Post group	yes	REST, 97 entry points	no	open, key per role	yes	yes, via ePost	not documented	certified, ELM 5.0 to 5.3
OdooOdoo S.A., Belgium	yes	XML-RPC, JSON-RPC, JSON-2 in v19	yes	open, except One App Free and Standard	yes	not documented	access point and SMP	certified basic, ELM 5.0 and 5.3
Run my AccountsRun my Accounts AG, Infoniqa group	yes	REST JSON and XML, plus Zapier	not documented	open, personal key	yes	not referenced at SIX	absent from the directory	not documented
SelectLineSelectLine Software GmbH, Swiss subsidiary	yes	REST JSON, Swagger and Postman	not documented	Premium edition, with Mobile Manager	yes	yes	not documented	certified basic, ELM 5.0
smallinvoiceLourens Systems	yes	REST v2, 102 paths	no	open from the Starter plan	yes	via Pingen	absent from the directory	not certified
WinBIZFiducial WinBIZ SA	yes	RPC-style HTTP JSON	not documented	reserved for approved partners	yes	yes	not documented	certified, Swissdec

SOURCES: VENDORS' TECHNICAL DOCUMENTATION, SWISSDEC REGISTER, OPENPEPPOL DIRECTORY AND SIX'S LIST OF EBILL NETWORK PARTNERS

Why the absence of a webhook has a price

A webhook is a message the software sends on its own as soon as an event occurs. Without it, the gateway has to ask in a loop whether something has changed, and it waits on average half its interval before seeing a change.

ONE QUERY EVERY FIFTEEN MINUTES, THAT IS SEVEN AND A HALF MINUTES OF WAITING ON AVERAGE

One query every fifteen minutes makes ninety-six calls per day and per client file, most of them useless. Multiply by the number of resources to watch, add the rate limits vendors apply without always publishing the threshold, and you get the real reason why a link that looked simple takes two days longer than planned.

Three ways to connect two programs, and when each is justified

Through the interface, when it exists and covers the need. It is the clean way. It assumes a key, a known quota and sufficient scope. Several vendors expose only part of their product. smallinvoice documents one hundred and two paths covering sales documents, none concerns creditors or accounting. Infoniqa publishes a serious interface on the finance side; payroll is absent from it.

Through files, when the interface is missing or closes. Crésus has no public API and works through import and export templates in text, CSV and XML ISO 20022. It is not a stopgap. A well-designed file exchange, deposited at a fixed time, checked and logged, holds for years without surprise. It simply requires accepting that information travels in batches and not to the second.

Through the browser, as a last resort. When neither interface nor file exists, an automaton can reproduce a user's gestures. This route breaks at the first screen redesign. We propose it only for a short, documented need, never as a foundation.

What we do with this table

Before writing the slightest line, we open your tools' documentation and check four points. Does the interface exist for a third party. Does it cover the data you need, not only the data the vendor puts forward. Can the key be obtained without a particular status. Does the quota hold the volume you really produce.

When an answer is no, we say so before starting, with the documentation page that establishes it. That avoids the quote promising real-time synchronisation on software that cannot alert. We sell no licences, and the diagnostic is free.

Where these answers come from

Every line of the table can be checked. Here is the documentation page read for each vendor, and the three official registers that are authoritative on compliance. The links open the vendor's or the body's website; they pass through no intermediary.

Vendors' documentation

AbacusREST interfaces portal
bexioREST 2.0 interface documentation
Banana Comptabilité Pluslocal web server and interface
CrésusEpsitec help centre
Infoniqa ONE 50 and ONE 200REST-API section of the online help
KLARAdeveloper portal
Odooexternal API reference
Run my AccountsREST-API support pages
SelectLineAPI online help
smallinvoiceSwagger v2 specification
WinBIZAPI Cloud category of the help centre

Official registers

SURVEY OF 23.08.2026. A VENDOR MAY PUBLISH TOMORROW WHAT IT DID NOT PUBLISH YESTERDAY; WE REVISIT THIS TABLE EVERY QUARTER.

Frequently asked questions

Is there an API for bexio, and is it open?

Yes. bexio publishes a REST interface in version 2.0, authenticated by OAuth 2.0 with OpenID Connect, and offers personal tokens for server-to-server exchanges. Registration is open, without going through partner status. The documentation read on 23 August 2026, however, describes no webhook, which forces polling the interface at regular intervals rather than receiving changes at the moment they occur.

Does Crésus have an API?

No, no public interface intended for third parties. Epsitec's documentation cites only outbound APIs, to PostFinance and to tilbago. Exchanges go through import and export templates in text, CSV and XML ISO 20022. It is not a defect in itself; it is a design constraint that changes how Crésus is connected to the rest of your tools.

Why is the WinBIZ API key not accessible?

The vendor writes that the key is obtained by becoming a partner under its general partnership terms, that a development key identifies a partner, that a production key identifies an application, and that any published application must be validated by Fiducial WinBIZ SA. An SME that wants a gateway written therefore has to go through someone who holds that status.

What is a webhook, and why does its absence cost a lot?

A webhook is a message the software sends on its own as soon as an event occurs, for example a paid invoice. Without a webhook, the gateway has to ask in a loop whether something has changed. It consumes quota, it reacts with a delay equal to its interval, and it costs more to write and to run. Of the eleven suites surveyed, only one documents webhooks.

Which Swiss software can send an invoice via eBill without going through a third party?

Of the eleven surveyed, Abacus, Crésus for issuing, Infoniqa on the ONE 200 side, KLARA via ePost, SelectLine and WinBIZ document a native connection. bexio goes through an app of its Marketplace, smallinvoice through Pingen. Banana announces the function as not available.

Is Peppol becoming mandatory for a Swiss SME?

No general obligation between companies exists in Switzerland to date. The question arises concretely at the moment of submitting an offer to a federal administration, not before. Of the eleven suites surveyed, only one is itself a Peppol access point.

How do you check that a vendor really is Swissdec-certified?

The official register at swissdec.ch publishes the product name, the level, the version of the ELM standard and the certificate number. Software that writes it is Swissdec-compatible without appearing in the register is not certified. We check this register for every tool before writing anything.

Are you a reseller of one of these programs?

We sell no licences. We build the links, we take over the data and we train the teams. The table above gives its sources; every statement can be checked on the website of the vendor concerned.

Where to go next

Let's check what your software can really exchange

Give us the names of your tools. We return the same analysis as above, applied to your case, with the documentation pages that establish it. The diagnostic is free.