Case study: Mid-market company connects Onesto booking with edi billing in 2 weeks

Digitalization in the mid-market rarely fails because of the idea. It usually fails in the time between decision and impact. That's exactly what a project at a mid-sized technology company in the DACH region illustrated — a company with around 420 employees, roughly 85 of whom travel regularly across sales, service, and project management.

The company had a familiar problem: trips were booked in Onesto, but billing then ran through a separate process. In between lay media breaks, manual transfers, and a high reconciliation burden in finance. On paper, everything worked. In practice, it took too long, was error-prone, and tied up capacity in places that a growing company should have been using more productively.

The starting point was typical for many mid-market CFOs. The company didn't want "yet another tool" — it wanted a seamless process from booking to billing. The goal was to transfer travel data from Onesto into edi without manual input, automate policy mapping, and noticeably reduce processing time in the finance department.

The bottleneck was not software, it was integration logic

The initial analysis identified two routes: classic middleware or a native API integration between Onesto and edi. The middleware option felt familiar, as it is considered standard in many IT landscapes. The catch: the project team estimated around eight weeks for implementation, mapping, testing, and error handling — plus ongoing costs for operations, monitoring, and adjustments.

In the end, the decision was consciously made against the "safe detour" and in favor of the direct API route.

The native integration between Onesto and edi went live in two weeks. That is not just a technical success — it is above all a business one. Going live six weeks earlier means realizing benefits sooner, reducing project risk, and relieving business units faster. In an environment where travel volumes, personnel costs, and compliance requirements are rising, implementation time is not a secondary consideration — it is a genuine competitive advantage.

What the process looked like before

Before the change, employees often had to partially re-enter or supplement booking data from Onesto in the expense report. Finance reviewed receipts, compared travel itineraries, checked policies, and corrected inconsistencies. Particularly with hotel invoices, rebookings, or multi-leg trips, this regularly led to follow-up queries.

The consequences were measurable:

- high manual effort in billing
- delayed month-end closes due to open travel transactions
- avoidable policy violations
- frustration among travelers and within finance

For the CFO, one point was especially critical: the costs arose not only from the process itself, but from the uncertainty within it. Every manual interface increases the error rate, extends throughput times, and makes forecasts less accurate.

The Integration: API-first instead of a middleware layer

Technically, the project was less spectacular than one might expect — and that was precisely its strength. Booking data from Onesto was transferred in a structured way to edi via native APIs. Relevant fields such as traveler, travel date, cost center reference, booking categories, and receipt context were immediately available in edi for billing.

The architecture was lean:

- Onesto as the leading system for travel bookings
- edi as the leading system for billing and downstream processing
- direct API communication without an additional middleware layer
- clear validation rules for mandatory fields and policy logic

The difference from middleware wasn't just speed. Native APIs also reduced technical complexity. Fewer components mean fewer sources of error, less maintenance effort, and lower dependency on external integration resources. In total, based on experience, implementation with native APIs runs around 60 percent faster and total cost of ownership is approximately 40 percent lower than with a middleware solution.

The business impact after just a few weeks

The effect was clear shortly after go-live. The company achieved a time saving of around 30 percent in the integrated booking-and-expense process. Policy violations dropped by 19 percent, because booking and billing data were more consistent and policies were no longer checked only after the fact.

The impact in finance was particularly significant. Processing time per expense report dropped noticeably, follow-up queries to employees decreased, and the month-end close became more predictable. At CFO level, that is not a comfort gain — it is hard economics.

Internally, the company calculated an ROI within less than six months. The reasoning was straightforward: when project costs are kept low, ongoing effort decreases, and productivity rises simultaneously in both finance and among travelers, the calculation quickly tips in favor of integration.

One statement from the responsible finance lead has stayed with me: "We didn't just digitalize a process. We removed a surface of friction." That captures the essence of projects like this. It's not about adding another system — it's about less operational friction.

What other mid-market companies can learn from this

First: integration speed is a strategic lever. Many companies evaluate projects too heavily on feature scope and too little on time-to-value. The question is often not which architecture can theoretically do everything, but which one delivers productive value within two to four weeks.

Second: API-first is not just an IT topic. Direct integrations reduce project scope, lower TCO, and cut down coordination effort between business units, IT, and external partners. Especially in the mid-market, where teams are lean, that is a decisive advantage.

Third: the greatest ROI usually lies in the unspectacular process steps. It's not the big innovation that delivers the first impact — it's the elimination of duplicate data entry, follow-up queries, and corrections.

Three concrete recommendations for decision-makers

1. Prioritize time-to-value over architectural perfection. If a native API integration can map the process stably within two weeks, that is often more economical than a larger middleware solution with a longer lead time.
2. Look at the end-to-end process. Booking and billing must not be planned as separate worlds. The benefit only materializes when data flows through without media breaks.
3. Calculate ROI using process costs, not just license costs. The real savings lie in reduced processing time, fewer errors, and better compliance.

For the company described, the decision in retrospect was not a technological bet but a management decision with a clear focus: implement quickly, avoid complexity, realize impact early. That is precisely where the real digitalization advantage lies for many mid-market companies today.

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