Finance & ERP · Integration
weclapp
Add weclapp to your product for your customers, and give your AI agents governed access to it.
weclapp is a German cloud ERP that puts CRM, order management, inventory and accounting inside one tenant, which is why an integration with it touches more of a business than a single-purpose connector does. The chain runs from an article through a quotation and a sales order to an invoice, with warehouse stock moving underneath it and ledger accounts and open items on the accounting side, so a write in one place has consequences in another. Two things shape the build. Its accounting is a real ledger with an account structure configured per company, so posting is mapped rather than assumed. And in accounting a duplicated document is not a bug report, it is a figure somebody has to explain, so writes carry an idempotency key and a retried call still lands once. fastn holds each tenant's credentials and carries the API changes.
In your product
Embedded for your customers. Per-tenant auth, no per-customer code, maintained by fastn.
Let each customer connect their own weclapp tenant so orders and invoices your product generates land in the system their finance team already uses.
Create a sales order or an invoice from an event in your product, with a retry that cannot post the document twice.
Read article and warehouse stock levels so your product quotes availability from the same numbers the warehouse works to.
Map each company's own ledger accounts and document numbering, because two weclapp tenants are rarely configured the same way.
For your AI agents
Governed, audited access for the agents you build, through the MCP server.
An agent reads open items and reports which invoices are overdue and by how much.
An agent checks stock for an article before it answers a question about availability.
An agent raises a document under governed permissions, and both the tenant and the event that prompted it are recorded.
Example prompt
Which weclapp invoices have gone past due without payment, and how much is riding on them?
Set up weclapp in 4 steps
- 01Enable the weclapp connector in your fastn dashboard.
- 02Have each customer authorise their own weclapp tenant so documents are created in their account.
- 03Map the article, sales order, invoice, stock and ledger account fields your product uses, per tenant.
- 04Call it from your product and expose the same connection to your agents through the MCP gateway.
Why teams use the weclapp integration
What you get by embedding it with fastn instead of building it yourself.
- Ship a weclapp integration without building it. Your customers connect their own weclapp account inside your product and work their invoices, payments and vendors there, with no per-customer code on your side.
- Handle the part that actually costs time: financial writes must be idempotent and reconcilable, because a duplicate is an accounting problem rather than a bug. fastn owns the auth, token refresh, rate limits, pagination and breaking-change fixes, so a weclapp update is not your on-call problem.
- One integration serves your product and your agents. The same governed weclapp connection powers in-product features and gives AI agents scoped, audited access, so you move financial records without hand-keying them between systems without wiring it twice.
Used by these teams
Compare with
Odoo
Xero
NetSuiteOften used alongside
Tools the same teams tend to run next to weclapp, across other categories.
Shopify
Stripe
BigCommerce
AfterShipweclapp integration FAQ
How do I add a weclapp integration to my product?
Enable the weclapp connector in your fastn dashboard, then let each customer authenticate their own weclapp account. fastn handles the OAuth flow, token storage and refresh per tenant, so there is no weclapp client code in your app and no per-customer branch in your codebase. Setup is 4 steps.
Do my customers each connect their own weclapp account?
Yes. Every connection is scoped to the individual customer, so each authorises their own weclapp account and only ever sees their own invoices, payments and vendors. That per-tenant isolation is the point of an embedded integration: you support the long tail of customer setups without maintaining an integration per customer.
Can AI agents use this weclapp integration?
Yes. The same connection is exposed to your agents through the fastn MCP gateway, with permissions scoped per tenant and every call audited. An agent reads open items and reports which invoices are overdue and by how much.
Who maintains the weclapp integration?
fastn does. When weclapp changes an endpoint, deprecates a field or alters its auth, the fix lands in the connector rather than in your backlog, and your customers' connections keep working.
Is the weclapp integration safe for financial writes?
Writes are idempotent, so a retry after a timeout does not post a document twice, and every call is logged per tenant so an entry can be traced back to the event that created it. That matters more in finance than anywhere else, because a duplicate is a number somebody has to explain.
Can it handle each customer's own chart of accounts?
Yes. ERP deployments are configured to the business, so account structures, required fields and fiscal calendars differ per customer. Those are mapped per tenant as configuration, not hard-coded.
What about weclapp rate limits during a first import?
Backfills are throttled deliberately. ERP limits are often account-wide rather than per-integration, so an unthrottled import can exhaust a customer's allowance and disrupt their other integrations.
What can I build with the weclapp integration?
A common starting point: let each customer connect their own weclapp tenant so orders and invoices your product generates land in the system their finance team already uses. Teams also use it for the other use cases listed above, and expose it to agents for governed reads and writes.
How much does the weclapp integration cost?
It is included. Pricing is based on connected accounts, not on how many connectors you enable, so adding weclapp does not change your per-connector cost. You can start free with 3 connected accounts.
Add weclapp to your product
Start free with 3 connected accounts. No sales call required, and no per-customer integration code.