For Swiss companies running Abacus
An Abacus MCP server gives Claude, ChatGPT or Copilot named tools for contacts, open invoices, projects and absences in Abacus ERP. It is built on the Abacus REST API, which authenticates a dedicated Abacus service user. Abacus Research ships no MCP server as of 21 September 2026, so Pexon builds one against your installation.
Why Abacus is hard for agents
01 · Installation
Each customer runs its own Abacus server, with its own base URL, release and entity catalogue. Abacus itself says to check the available APIs on the installation. The tool list is therefore checked against your server and release, not against a generic reference.
02 · Identity
The REST API authenticates a service user with client credentials, not the person asking. A service user cannot log into Abacus and sees what its role allows. Keeping answers inside each person's own rights means the connector has to map the user to their Abacus role before it answers, and that mapping is tested in the blueprint.
03 · Mandants
Multi-mandant installations put the mandant in every URL path. An agent has to know which company a question is about before it can call anything, so mandant routing is part of every tool, not an afterthought.
04 · Legacy
Some modules, such as Ababau, are only reachable through the older AbaConnect SOAP interface. It allows one session per user and one active request at a time, which limits how many questions can run in parallel against those modules.
Checked 21 September 2026
| What we found | |
|---|---|
| Interfaces | Abacus REST API (Entity API) (REST/JSON, docs public): entity endpoints per mandant, with a Swagger UI on the customer's own Abacus server; the endpoint catalogue differs per annual release, so the installation is the reference · Change subscriptions (SubscribeChanges, ConsumeChanges, AcknowledgeChanges) (REST/JSON, docs public): a polling change feed, no webhooks · AbaConnect (SOAP, docs public): legacy web-service interface with username and password sessions, one session per user and one active request at a time; some modules, such as Ababau, are only reachable here |
| Authentication | The REST API uses OAuth 2.0 client credentials with a dedicated service user (client ID and secret) set up in Abacus user management; tokens are valid for about 600 seconds. Service users cannot log into the Abacus interface. AbaConnect uses username and password. |
| Vendor MCP server | No vendor server. No MCP server from Abacus Research; searches for an Abacus MCP server return unrelated projects, and Swiss agencies advertise custom builds. |
| Vendor AI assistant | Abacus Intelligence, since version 2025 and built with Artificialy SA, adds chat and voice commands in AbaMenu (including Swiss German), text generation, DeepO document recognition and the AbaClik AI app inside Abacus. |
| Other connectors | Maesn offers a unified accounting API over Abacus (accounting objects only), PepperShop an e-commerce connector, and Power Partners read-only Power BI reporting; none of them is an agent connector. |
Abacus Research AG (CH). Swiss SMEs, trustees and public administrations; Wikipedia puts the Abacus customer base at about 65,000.
What we build
Built on what Abacus Research AG documents: customers and contacts (subjects), projects, journal entries, customer invoices, supplier bills, payments, absences (from release 2026). Backends named below are documented resources; "confirmed in blueprint" means the vendor documentation sits behind a login and the resource is checked against your release first.
# abacus-mcp-server: tool manifest, draft for blueprint week 1
# Every tool runs as the person asking. Nothing is written without a person confirming.
tools:
find_contact: # name or number -> matching customer or supplier subjects with address data
backend: Abacus REST API, resource confirmed in blueprint
mode: read
get_open_customer_invoices: # customer, due-date range -> open invoices with amount and due date
backend: Abacus REST API, resource confirmed in blueprint
mode: read
get_project_status: # project number -> project master data and booked values
backend: Abacus REST API, resource confirmed in blueprint
mode: read
list_absences: # date range, team -> employee absences
backend: Abacus REST API (release 2026), resource confirmed in blueprint
mode: read
draft_journal_entry: # account, amount, text -> journal entry proposal for a person to confirm before posting
backend: Abacus REST API, resource confirmed in blueprint
mode: propose
audit: every call logged with user, tool, arguments and the Abacus responseThe manifest is the contract. A question that needs an operation not on it gets a new line and a review, not a wider permission.
Abacus holds the records. An assistant without a governed way in answers from whatever someone pasted into the chat. The connector is the governed way in: named operations, the person's own permissions, every call logged.
When this is the wrong page
If your users work inside Abacus and want chat, voice commands or document recognition there, Abacus Intelligence is the shorter path and Abacus maintains it. A connector is right when the assistant lives in Claude, ChatGPT or Copilot, or has to combine Abacus with another system.
Two weeks, €4,900 fixed price. Week one agrees the tool list with your Abacus owners and checks every backend against your release and licence. Week two tests whether a person's own Abacus permissions reach through the connector. You keep the manifest and a costed build plan, whoever builds it. All prices are net and exclude VAT.
What we need from you: a named Abacus administrator, a test or sandbox system we may call, and one business owner who can say which questions the assistant should answer first. The first production connector is usually a use-case pilot from €15,000; it runs in your environment, and the code is yours.
Not as of 21 September 2026. Abacus Research offers Abacus Intelligence inside the product, with chat and voice commands in AbaMenu, and a REST API on each customer's Abacus server. An MCP server for assistants outside Abacus has to be built against that API.
Possibly. The REST API needs a service user set up in Abacus user management, and whether that service user counts against your user licences, or whether REST access has to be enabled for your installation, is a question to check with Abacus Research. The blueprint answers it before any build starts.
No. The Abacus REST API runs as a service user, so the connector scopes that user to the agreed mandants and entities and checks each person's Abacus role before it answers. Two users asking the same question can get two different answers, and that is tested before go-live.
The two-week Readiness Blueprint is fixed at €4,900: agreed tool list, backends checked against your release, identity tested end to end, costed build plan. The production connector is usually a use-case pilot from €15,000. Prices are net, excluding VAT.
Next step
Thirty minutes with the engineer who would build the connector, with your Abacus administrator in the room if you like.