Finance & ERP · Integration
Quaderno
Add Quaderno to your product for your customers, and give your AI agents governed access to it.
Quaderno serves its API from a per-account subdomain on quadernoapp.com, so the first call in any integration is the authorization lookup that tells you which host to use for that account; hardcoding one host breaks the moment you add a second customer. The document objects are invoices, credits, expenses, estimates and receipts, each with its own numbering sequence, and once a document is issued the numbering is fixed, so corrections are made by issuing a credit rather than editing the original. There is a separate tax calculation endpoint that returns the applicable rate and jurisdiction for a transaction, which is what most people actually want rather than an invoice write, and it evaluates customer location evidence rather than a single country field. Rate limit headers are returned on every response and are worth honouring, as the limit applies per account. fastn holds each customer's Quaderno key, resolves their account host on connect, and keeps that mapping current as accounts move.
In your product
Embedded for your customers. Per-tenant auth, no per-customer code, maintained by fastn.
Let a customer connect their own Quaderno account so invoices are issued under their numbering and tax settings
Calculate the correct sales tax or VAT rate at checkout using the customer's location evidence
Issue invoices and receipts automatically when a payment settles in your billing system
Post credits for refunds instead of editing issued documents, keeping the audit trail intact
For your AI agents
Governed, audited access for the agents you build, through the MCP server.
Let an agent read invoices and payment status but require approval before issuing or crediting any document
Have an agent answer tax rate questions by calling the calculation endpoint rather than guessing a rate
Audit per tenant which documents an agent viewed or created, with the account host it used
Example prompt
What VAT rate applies to a digital subscription sold to a customer in Ireland, and what have we invoiced them this quarter?
Set up Quaderno in 4 steps
- 01Enable the Quaderno connector from your fastn dashboard.
- 02Have each customer authorise their own Quaderno account, so calls run under their credentials rather than a shared key.
- 03Decide which invoices, payments and vendors your product needs, map those fields, then enable the actions and triggers you want.
- 04Call it from your product and expose it to your agents through the same governed connection.
Why teams use the Quaderno integration
What you get by embedding it with fastn instead of building it yourself.
- Ship a Quaderno integration without building it. Your customers connect their own Quaderno 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 Quaderno update is not your on-call problem.
- One integration serves your product and your agents. The same governed Quaderno 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
NetSuite
QuickBooks
XeroOften used alongside
Tools the same teams tend to run next to Quaderno, across other categories.
Shopify
Stripe
BigCommerce
AfterShipQuaderno integration FAQ
How do I add a Quaderno integration to my product?
Enable the Quaderno connector in your fastn dashboard, then let each customer authenticate their own Quaderno account. fastn handles the OAuth flow, token storage and refresh per tenant, so there is no Quaderno client code in your app and no per-customer branch in your codebase. Setup is 4 steps.
Do my customers each connect their own Quaderno account?
Yes. Every connection is scoped to the individual customer, so each authorises their own Quaderno 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 Quaderno integration?
Yes. The same connection is exposed to your agents through the fastn MCP gateway, with permissions scoped per tenant and every call audited. Let an agent read invoices and payment status but require approval before issuing or crediting any document
Who maintains the Quaderno integration?
fastn does. When Quaderno 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 Quaderno 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 Quaderno 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 Quaderno integration?
A common starting point: let a customer connect their own Quaderno account so invoices are issued under their numbering and tax settings. 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 Quaderno integration cost?
It is included. Pricing is based on connected accounts, not on how many connectors you enable, so adding Quaderno does not change your per-connector cost. You can start free with 3 connected accounts.
Add Quaderno to your product
Start free with 3 connected accounts. No sales call required, and no per-customer integration code.