Clockin creates invoices in the accounting system each customer already runs.
Clockin's users log their hours on a building site, on a care round or behind a counter. What has to happen next is office work: the tracked time has to become an invoice, and it has to become one inside the accounting system that customer already books in.
Clockin made its integrations a reason customers come to it
“We use Maesn to successfully leverage integrations and partnerships as a key driver for lead generation and expansion into new markets and customer segments. By connecting Clockin to our customers' accounting systems, project data flows directly into their existing tools, ensuring a smooth, reliable data exchange with the systems they already use.”
Who Clockin is, and where Maesn sits in it
- Website
- clockin.de
- About Clockin
- Founded in Münster in 2018. More than 8.500 businesses across more than 50 industries run on clockin, and in September 2025 the company raised a 10 million EUR Series A led by Newion and NRW.Venture.Source: clockin.de
- Use case
- Project-related invoices out of tracked working hours. The study names what has to travel with them: customer data, line items, prices with VAT and order numbers. The workflow itself, independent of any one customer, is on the invoice creation page.
- Previous solution
- Manual creation of invoices in the accounting system.
- Accounting systems
- Sage Active, Lexware Office and sevdesk
- Endpoints
- Post InvoiceGet CustomersGet Suppliers
The accounting system changes with every customer Clockin adds
Clockin sells to small and mid-sized businesses, and each one books in whatever accounting product it already had. How many systems Clockin has to reach is set by its customers, not by its own size.
The published study gives the reason in one line: such a wide variety of tools in use, from Sage to international platforms, that building the integrations in-house was unrealistic. That variety is a property of the customer base rather than a phase Clockin could grow out of. Its own site counts more than 50 industries, from trade businesses and care services to physio practices and restaurants, and the accounting product was in place in each of them before Clockin was: the previous solution the study names is a person keying the invoice into it by hand.
The shape of the problem is the opposite of an enterprise one. Instead of a few large installations there are many small ones, and every business that switches the integration on is its own account in its own accounting system, with its own consent to obtain and its own connection to keep working. Unified authentication is the part of Maesn that carries that, so growing the number of connected businesses does not grow the number of things Clockin has to operate.
Clockin looked at building and maintaining the relevant integrations itself and called it unrealistic. The study names the three things it would have cost:
- Significant resources to develop and maintain them
- Product development slowed down
- The team distracted from its core focus
One connection, and every new accounting system comes with it
Two reads to find out who the invoice is made out to, one write to put it where it will be booked. The same three calls against every connected system, through one API.
What comes out of the write is a draft, and the study is precise about that: workflows to create draft invoices based on project data. The document arrives where it will be checked and sent, in the system the business already runs its billing in, so the tracked hours turn into an invoice without anybody retyping them and without Clockin taking over the part its customer is liable for.
What makes those three calls the same three everywhere is the layer underneath. Every accounting system names and shapes a customer, a supplier and an invoice line differently, and the common data model resolves that before any of it reaches Clockin's code. Clockin writes the invoice once, and it writes it the same way whether the business behind it books in Sage Active, in Lexware Office or in sevdesk.
In two weeks the integrations brought in 800+ inbound leads
The figure is the study's own headline, and it is the only hard outcome number Maesn publishes about any of the four written-up customers.
The study puts the other half of it in Clockin's own terms: the team can now focus fully on delivering value to customers and accelerating go-to-market. And Fabian Ebbert names the integrations as a driver for lead generation and for expansion into new markets, which is the same thing the figure above measures, said as a strategy rather than as a result.
The part that decides whether that repeats is coverage, and it can be measured rather than promised. Across the 29 connected accounting systems, ten are marked as accepting an invoice you write, and every one of those ten also reads customers and suppliers. Clockin's three published endpoints are therefore complete on all ten, and the three systems it named are three of them. The study publishes which three came first, not why, and the coverage says only what the remaining seven would take: the same three calls, nothing new to build.
Reading the counterparty before writing the invoice is a workflow of its own, and it is the same one wherever a product has to keep its own records lined up with an accounting system: customer and supplier data sync covers it on its own terms. The published outcome here is a demand number rather than an engineering one, which is why this study is the one go-to-market teams are pointed at.
Common questions
Which accounting systems does Clockin connect to through Maesn?
What does the integration actually call?
Why a draft invoice rather than a finished one?
Where does the figure of 800 inbound leads come from?
Did Clockin consider building the integrations itself?
Can another product that bills tracked work use the same setup?
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