MoneyMonk + Lightning Checkout: Bitcoin for zzp invoices | payinbtc.me

MoneyMonk is written for one person: the Dutch zzp'er who writes hours. The product says so directly, and the feature list follows from it. Urenregistratie and ritten per project, kosten booked where they belong, bonnetjes scanned from the app, free PSD2 bank couplings with ING, Rabobank, ABN AMRO, Knab, Triodos, ASN and bunq, btw-aangifte and ICP-aangifte, and the figures ready for your inkomstenbelasting. Plans run from a free starter year for new entrepreneurs up to 37.50 euros a month, cancellable monthly. It is a good piece of software for a specific job.

The invoice at the end of that chain has one online payment method, and it comes with a condition. To let a client pay a MoneyMonk factuur with iDEAL or Wero, you need a Mollie account, opened separately and connected to MoneyMonk. That works, and Mollie feeds the transactions back in daily. It also means your single online payment option depends on a merchant relationship you maintain with a third party, priced per transaction: 32 cents for iDEAL, 1.80% plus 25 cents for a consumer card issued in the EEA, 3.25% plus 25 cents for one issued outside it. Bitcoin appears nowhere in MoneyMonk or in its integration list.

Lightning Checkout is a Bitcoin payment provider founded in 2022 and part of BTC2B Group, the same group that operates PayInBTC.me. Worth saying at the top: this is not a neutral write-up of an unrelated provider, and you should read the recommendation with that in mind. It works in Dutch and English, routes payments over the Lightning Network for smaller amounts and on-chain for larger ones, consolidates payouts once a day, and states plainly that it has no control over the Bitcoin sent at any point.

The pricing is where this gets interesting for a zzp'er specifically, because your invoices are large. Lightning Checkout charges 1% per transaction, with your total capped at 5,000 sats per month, roughly 5 euros. On a 4,000 euro month of hours, the 1% would be 40 euros and the cap brings it to about 5. PayInBTC.me adds a flat 1,500 sats per invoice, or 2,500 sats a month for unlimited invoices. A percentage that stops climbing is an unusual thing to find on the payment side of a freelance business.

PayInBTC.me connects the two, and the whole setup takes about five minutes. Your MoneyMonk connection is read-only: we read the invoice amount, currency and factuurnummer so the payment page shows the right total, and we cannot touch your uren, your ritten, your bonnetjes or your btw-aangifte. From then on the invoices you choose carry a Bitcoin link next to your iDEAL button, visible in the Klantportaal alongside it.

Why MoneyMonk and Lightning Checkout fit a zzp'er billing hours

Few large invoices are the worst case for percentage pricing, and the best case for a cap

Card rates were designed for many small transactions. A zzp'er is the opposite: a month of hours arrives as one invoice, often somewhere between 2,000 and 8,000 euros, sometimes just one or two of them a month. At Mollie's EEA consumer rate of 1.80% plus 25 cents, a 4,000 euro invoice costs around 72 euros to collect; at the non-EEA rate of 3.25% plus 25 cents, around 130. Lightning Checkout charges 1% with the total capped at 5,000 sats a month, so the same 4,000 euro invoice costs about 5 euros on their side regardless of whether your rate card says 60 an hour or 160. The bigger your invoices get, the further apart those two numbers move.

The cap is monthly, which matters if you invoice more than one client

Read the ceiling carefully, because it is not per payment. Whatever you collect in Bitcoin during a calendar month, Lightning Checkout's share tops out at 5,000 sats in total. One 3,000 euro invoice costs about 5 euros. Three invoices of 3,000 euros in the same month still cost about 5 euros between them. For a zzp'er with two or three clients on parallel retainers, that turns the Bitcoin option from something you offer the one client who asked into something worth offering all of them.

One merchant relationship instead of two

Offering iDEAL on a MoneyMonk invoice means keeping a Mollie account in good standing: its onboarding, its statements, its terms. Adding a Bitcoin option through Lightning Checkout is a single signup with a Lightning address and no ongoing merchant obligations, and it advertises no contract and no cancellation period. Because Lightning Checkout and PayInBTC.me are part of the same group, it is also one place to ask when something looks wrong, rather than each company pointing at the other.

Invoice sizes that sit above the Lightning comfort zone

This pairing has a wrinkle worth understanding rather than glossing over. Lightning is at its best up to a few hundred euros, and a month of billed hours is usually more than that, so most zzp invoices will route on-chain. Lightning Checkout recommends configuring an on-chain wallet with an XPUB above roughly 500 euros for exactly this reason. On-chain confirmation takes minutes rather than seconds, which is still faster than SEPA, and it settles to addresses derived from a key you hold. Set the XPUB up at signup and the rest is automatic.

A monthly fee invoice you can book in one line

Zzp'ers using MoneyMonk usually do their own bookkeeping between projects, so the admin cost of a payment method matters as much as its rate. Lightning Checkout sends a monthly invoice showing its fees with VAT, rather than shaving a percentage off each receipt. That books as one supplier line a month, which is a shorter job than working out what a processor deducted from which payout before the btw-aangifte is due.

How the integration works

Setup takes about five minutes and needs no crypto knowledge beyond somewhere to receive payments. After that, every invoice you flag carries the option automatically.

Create your Lightning Checkout account

Register with Lightning Checkout and give them the Lightning address payments should arrive at, which looks like an email address and comes from any Lightning wallet. Because a month of billed hours usually exceeds a few hundred euros, add the XPUB of an on-chain wallet at the same time so larger invoices settle there. Lightning Checkout confirms the account by email, typically within a day.

Connect MoneyMonk to PayInBTC.me

Sign in to PayInBTC.me, choose MoneyMonk, and authorise the connection to your account. The access is read-only and limited to invoice data: amount, currency, factuurnummer and client name. We cannot create or change a factuur or offerte, touch your urenregistratie, ritten or bonnetjes, reach your bank couplings, or see your btw-aangifte. Unlike the Mollie account behind your iDEAL button, there is no merchant relationship to maintain on our side.

Link your Lightning Checkout account

Add your Lightning Checkout credentials in PayInBTC.me and choose which invoices carry the Bitcoin option. Because the fee ceiling is monthly, offering it to every client costs the same as offering it to one, so there is no reason to be selective beyond your own preference.

Write your hours and invoice as usual

Register uren against the project, generate the factuur from it the way you always do, and send it. The Bitcoin link travels with the invoice next to your iDEAL button and your bank details, and appears in the Klantportaal alongside them. Your layout, numbering, offertes and btw settings are untouched, and clients who prefer iDEAL keep using iDEAL.

Get paid and get notified

Your client opens the link, sees the invoice total converted to Bitcoin at that moment's rate, and pays by scanning a QR code from any wallet. Lightning payments clear in seconds and on-chain payments in minutes. PayInBTC.me emails you when it lands, and you mark the factuur as paid in MoneyMonk.

What a zzp'er gets from this pairing

The fee stops before your rate does

Raise your hourly rate and a percentage-based method quietly takes more from every invoice. Lightning Checkout's 1% stops at 5,000 sats a month, about 5 euros, and PayInBTC.me charges 1,500 sats per invoice or 2,500 sats a month flat. A 2,000 euro month and an 8,000 euro month cost the same to collect.

Several clients for the price of one

The ceiling covers everything you collect in Bitcoin that month, not each payment separately. Two or three clients paying in Bitcoin cost the same in provider fees as one, which is the opposite of how every card rate you have ever paid behaves.

A foreign client stops being an expensive client

A card issued outside the EEA runs at 3.25% plus 25 cents through Mollie, so one client in London or New York can cost more in payment fees than all your Dutch clients combined. Over Bitcoin, where the client sits makes no difference to the cost or the speed.

Cash in hand the same evening

iDEAL and SEPA settle on banking days. A Lightning payment clears within seconds at any hour, including a Friday night or a Sunday, and on-chain payments in minutes. When your cash position is one person's invoices, the difference between hours and days is not academic.

Bitcoin that arrives in your own wallet

Lightning payments go to the address you nominated, and larger on-chain amounts to addresses derived from an XPUB you hold, so nobody else has your keys. Lightning Checkout states it has no control over the Bitcoin sent, and PayInBTC.me never touches funds at all, group relationship or not.

Everything MoneyMonk does for you keeps working

Urenregistratie, ritten, kosten per project, bonnetjes from the app, the free PSD2 bank couplings, the Klantportaal, your btw-aangifte and ICP-aangifte and your inkomstenbelasting figures all carry on unchanged. The connection is read-only, so nothing can be written into your administratie.

What it costs on a typical invoice

Take a 4,000 euro invoice, a normal month of billed hours for a Dutch zzp'er at a mid-range rate. The comparison uses Mollie's published rates, because Mollie is what sits behind the iDEAL button on a MoneyMonk invoice.

Method	Cost on a €4,000 invoice	Notes
iDEAL or Wero, Dutch client	€0.32	A flat fee per transaction through Mollie, and the right answer whenever your client banks in the Netherlands
Consumer card issued in the EEA	About €72.25	1.80% plus €0.25 through Mollie; a commercial or corporate card is 2.90% plus €0.25, which would be about €116.25
Card issued outside the EEA	About €130.25	3.25% plus €0.25 through Mollie, the usual case for a client in the UK, Switzerland or the US
Bitcoin via PayInBTC.me and Lightning Checkout	About €6.50	Lightning Checkout's 1% would be €40, but your total is capped at 5,000 sats per month, about €5, plus a flat 1,500 sats to PayInBTC.me, about €1.50

For a Dutch client, iDEAL at 32 cents is the cheapest thing on this page and nothing here changes that. The comparison worth sitting with is the last two rows. One foreign client paying by card costs you 130 euros on this invoice, roughly a billable hour, and the same payment over Bitcoin costs about six and a half. Then look at what the table cannot show: invoice a second client in Bitcoin that same month and Lightning Checkout's 5 euros does not become 10, because the ceiling is monthly. The card row simply doubles. Repeat that across a year of retainer work and it becomes a number worth a five-minute setup.

Who this fits

Zzp'ers with one or two clients abroad

Developers, designers and consultants billing hours to a client in Germany, the UK or the US. iDEAL does not reach them, so the fallback is a card at 1.80% or 3.25%, or a transfer that turns up when it turns up. This is the case where the Bitcoin option pays for itself on the first invoice.

Freelancers on monthly retainers

The same invoice, the same amount, twelve times a year. A percentage compounds quietly across those twelve, and a fee that stops at 5 euros a month does not. The recurring invoice you already generate from your hours carries the Bitcoin link automatically once it is switched on.

Zzp'ers billing several clients in parallel

If three clients pay you every month, the monthly ceiling is doing the most work for you: their combined Bitcoin payments cost the same in provider fees as a single one. Offering the option across your whole client list costs nothing extra to try.

Zzp'ers who already hold some Bitcoin

If part of what you earn ends up in Bitcoin anyway, being paid in it directly removes the exchange account, its verification and its fees from the loop. How you record and value the holding before your inkomstenbelasting is a question for your accountant, and worth asking early rather than in April.

Getting started

You need a MoneyMonk account and a Lightning Checkout account. Because zzp invoices are usually above a few hundred euros, set up the on-chain XPUB at signup rather than later. PayInBTC.me handles the connection between the two.

Register with Lightning Checkout, give them the Lightning address payments should arrive at, and add the XPUB of the on-chain wallet you want larger invoices to settle to.
Create your PayInBTC.me account and authorise the read-only MoneyMonk connection.
Add your Lightning Checkout details, switch the Bitcoin option on, and send one invoice as a live test before you offer it across your client list.

The first month is free, with three free invoices on pay-per-use, so a real month of hours can go through the setup before you decide whether it stays. Full setup instructions are at docs.payinbtc.me.

Get started free →

Frequently Asked Questions

Does this change how I write hours and invoice in MoneyMonk?

No. You register uren and ritten against your projects and generate the factuur exactly as you do now, with the same layout, numbering, offertes and btw settings. PayInBTC.me adds a Bitcoin payment link to the invoices you choose, next to your iDEAL button and your bank details. Our connection is read-only, so nothing in your administratie is written to by us.

Do I still need my Mollie account?

Only if you want to keep offering iDEAL, and most zzp'ers do because it is 32 cents for a Dutch client. This does not replace Mollie or interfere with it: the Bitcoin link sits next to the iDEAL button rather than instead of it. If Mollie is in your setup mainly for occasional card payments from abroad, that is the part worth reconsidering, because those are the payments costing you 1.80% to 3.25%.

What does Lightning Checkout charge, and what does PayInBTC.me cost per invoice?

Lightning Checkout charges 1% per transaction, with your total capped at 5,000 sats per month, about 5 euros at recent prices. That ceiling covers everything you collect in Bitcoin that month rather than each payment on its own, so a 4,000 euro invoice costs about 5 euros on their side, and a second invoice the same month costs nothing further. PayInBTC.me is 1,500 sats per invoice on pay-per-use, about 1.50 euros, or 2,500 sats a month for unlimited invoices, about 2.50 euros, or 25,000 sats a year. The first month is free, with three free invoices on the pay-per-use plan.

Are Lightning Checkout and PayInBTC.me the same company?

Not the same company, but part of the same group, BTC2B Group. You should know that when you read us recommending them. What it means in practice is that the two products were built to work together and there is one place to ask when something goes wrong. What it does not change is custody: neither company holds your Bitcoin at any point, since payments settle to your own Lightning address or to addresses derived from your XPUB. If you would rather use a provider unconnected to us, the MoneyMonk hub lists thirteen others, and BTCPay Server is open-source software with no company behind it at all.

My invoices are thousands of euros. Is Lightning not for small payments?

Lightning is at its best up to a few hundred euros, which is below a typical month of billed hours, so most of your invoices will route on-chain. That is why Lightning Checkout recommends adding an on-chain wallet with an XPUB above roughly 500 euros. On-chain confirmation takes minutes rather than seconds, still well ahead of a SEPA transfer, and it settles to addresses derived from a key you hold. Configure the XPUB at signup and the routing happens without you choosing per invoice.

Where does the Bitcoin end up, and who holds it in the meantime?

With you. Lightning payments arrive at the Lightning address you registered with Lightning Checkout, and on-chain payments at addresses derived from your XPUB, which lets addresses be generated without anyone else having your keys. Lightning Checkout states it has no control over the Bitcoin sent at any point, and PayInBTC.me never touches funds: we read invoice data and build the payment page.

Will MoneyMonk mark the factuur as paid automatically?

Not today. Our access is read-only, so we cannot write a payment into your administratie. We email you the moment the Bitcoin clears and you mark the factuur as paid yourself, the same handling as a payment that arrives outside your bank koppeling. Automatic reconciliation is on our roadmap and we will call it available when it ships.

I invoice clients outside the Netherlands. Does this still work?

Yes, and those are the invoices this is for. Bitcoin has no supported-country list on the paying side, so a client anywhere with an internet connection can settle a euro invoice, with no international card surcharge and no correspondent bank in the middle. What depends on jurisdiction is your own provider account, so check Lightning Checkout's terms for a Dutch eenmanszaak or BV before you rely on it.

More questions? See our full FAQ →

Accept Bitcoin on MoneyMonk Invoices with Lightning Checkout