Connect SnelStart with slimzaak
slimzaak isn't a replacement for SnelStart — it's the invoicing and admin tool that prepares everything before it lands in your bookkeeping. You connect SnelStart to slimzaak with an API key, no fiddly OAuth login screen, just paste in a key and you're done. From there, your customers, sales invoices, expenses, and receipts flow through to SnelStart automatically, with your VAT return sitting ready to file. Many SnelStart users are freelancers and small business owners, exactly the audience slimzaak's Free Freelancer plan is built for: you start invoicing at no cost and let everything flow automatically into your existing SnelStart bookkeeping.
We deliver the bookkeeping entries to your package.
Invoice → slimzaak → SnelStart
- 01
Connecting
Connect with an API key, no OAuth hassle
With most other accounting packages, you log in through an OAuth screen to authorize the connection. SnelStart works differently: you connect slimzaak using an API key from your SnelStart account. In practice that's quicker to set up, and you won't need to keep logging back into SnelStart to keep the connection active.
- Connect using an API key from your SnelStart account, no OAuth login screen required
- Set up once, then the connection stays active
- Runs alongside your existing SnelStart bookkeeping, nothing gets overwritten
- Also works if your accountant manages the SnelStart bookkeeping
- 02
Syncing
Customers, invoices, and expenses land in SnelStart automatically
Once the connection is set up, slimzaak syncs with SnelStart automatically. Your customers and contacts are created there, sales invoices are posted as sales entries, and expenses and receipts — already scanned and read automatically by slimzaak's AI scanning — land as purchase entries. You don't have to retype or import anything yourself.
- Customers and contacts created automatically in SnelStart
- Sales invoices posted automatically as sales entries
- Expenses and receipts, already read by the AI scan, posted as purchase entries
- No more manual retyping or separate imports
- 03
VAT return
VAT return prepared, you or your accountant files it
slimzaak prepares your VAT return data in SnelStart based on your sales and purchase entries. You or your accountant then files the return yourself from SnelStart with the tax authorities. slimzaak never files anything on its own — that always stays with you or your accountant in SnelStart.
- VAT return data automatically prepared in SnelStart
- You or your accountant files with the tax authorities directly from SnelStart
- slimzaak never files a VAT return itself
FactuurFactuur 2026-0455
Sanne Bakker · 17 mei 2026
Btw & OSSFrequently asked questions
How do I connect SnelStart to slimzaak?
Does slimzaak replace my SnelStart bookkeeping?
What exactly gets synced with SnelStart?
Does slimzaak file my VAT return with the tax authorities?
Connect SnelStart and automate your admin
Start invoicing for free in slimzaak and let your customers, invoices, and expenses flow automatically into your existing SnelStart bookkeeping.
Free plan available · No credit card required