Twinfield integration
Twinfield integration: your books ready for your accountant automatically
slimzaak connects directly to Twinfield via OAuth2, the cloud accounting package many accounting firms use to manage multiple clients' books. Once connected, slimzaak automatically syncs your customers, sales invoices, and expenses with Twinfield, including the receipts slimzaak already captured for you with AI scanning. slimzaak doesn't replace Twinfield — it's the invoicing and bookkeeping tool that prepares everything before it lands with your accountant in Twinfield. If you work with an accountant who uses Twinfield, you invoice and scan in slimzaak, and your accountant finds everything neatly waiting.
- 01
Connecting
Your Twinfield administration connected in minutes
You connect slimzaak to Twinfield through a secure OAuth2 integration — you log in to Twinfield and authorize the connection, without ever sharing passwords with slimzaak. If you work with an accountant who manages multiple clients in Twinfield, slimzaak fits right into that workflow: you handle your own invoicing and receipts, while your accountant keeps an overview per client administration in Twinfield.
- Connect via OAuth2, no passwords shared
- Up and running in minutes, no technical knowledge needed
- Fits your accountant's client administrations
- You keep slimzaak as your invoicing and scanning environment
- 02
Syncing
Customers, invoices, and receipts synced to Twinfield automatically
Once the connection is active, slimzaak syncs with Twinfield automatically. Your customers and contacts are added, sales invoices are posted automatically as sales entries, and expenses and receipts — already captured automatically by slimzaak's AI scan — come in as purchase entries. You never have to enter anything twice: whatever you invoice or scan in slimzaak ends up neatly booked in Twinfield.
- Customers and contacts synced automatically
- Sales invoices posted automatically as sales entries
- Expenses and receipts (AI scan) posted automatically as purchase entries
- No double entry between slimzaak and Twinfield
- 03
VAT return
VAT data prepared for you, filing stays in Twinfield
slimzaak prepares your VAT return data in Twinfield, neatly linked to your sales and purchase entries. You or your accountant then file the return yourselves from Twinfield with the Tax Authorities. slimzaak never files anything on its own — control and responsibility always stay with you and your accountant.
- VAT return data prepared in Twinfield
- Filing with the Tax Authorities is done by you or your accountant
- slimzaak never files anything automatically
Btw & OSSFrequently asked questions
How do I connect slimzaak to Twinfield?
You authorize the connection via OAuth2 directly from slimzaak; it's set up in a few minutes and you never need to share passwords. After that, slimzaak automatically syncs your customers, sales invoices, and expenses with Twinfield.
Does slimzaak replace Twinfield?
No. slimzaak is your invoicing and bookkeeping tool: you create invoices and scan receipts with AI, and slimzaak prepares everything in Twinfield. Twinfield remains the accounting package where your accountant runs the final administration.
I work with an accountant who uses Twinfield for multiple clients. Does slimzaak fit that setup?
Yes, that's exactly what this integration is built for. You invoice and scan receipts in slimzaak, and your accountant automatically finds everything ready in your shared Twinfield administration, with nothing to retype by hand.
Does slimzaak file my VAT return with the Tax Authorities?
No. slimzaak prepares the VAT return data in Twinfield, but you — or your accountant — always file the actual return yourselves from Twinfield with the Tax Authorities. slimzaak never files anything on its own.
Connect slimzaak to Twinfield
Start invoicing and scanning receipts in slimzaak, and watch your customers, invoices, and expenses show up automatically in Twinfield for your accountant.
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