Beyond the belt: How smart sorting moves the business

Ask anyone who’s lived through peak season, and they’ll tell you: smart sorting makes or breaks your capacity.

And it’s never just about the machine. Behind every upgraded conveyor, shoe sorter, or fleet of warehouse robots, there’s a deeper story — of careful calibration, tight margins, and teams tweaking every corner of the process to make it work.

This month, we go behind the belt to explore what actually changes when you get sorting right. Read on for a deep dive into sorting systems with D Express, an express courier service delivering 65,000 parcels a day, and global examples that show what happens when people, process, and tech align.

From manual to machine: Inside D Express’ sorting evolution

D Express is one of the leading express courier services in Serbia, delivering over 65,000 parcels a day across the country, with a fleet of some 800 vehicles and 1,200 employees. Having introduced parcel lockers in Serbia back in 2020, the company has steadily evolved its operations through its data-informed approach, reshaping how parcel delivery works in the country.

We spoke with Milan Stojković, IT Director at D Express, who walked us through how the company went from manual sorting to automation, and how this allowed them to scale their operations efficiently.

Before automation however, sorting at D Express was a fully manual operation. Pallet positions were laid out, and workers sorted parcels by hand according to destination. As the number of delivery centers grew, so did the complexity, and the walking.

“For example, if you have six centers, that’s six pallet stations. With 25 centers, that’s 25 stations. Every movement added up. People would be slower, and mistakes would happen”, says Milan.

The inefficiency pushed the team to explore ways to speed things up — and eventually automate.

The conveyor changed everything, but didn’t solve it all

The first leap forward was installing a conveyor belt system. It wasn’t yet a fully automated solution, but it eliminated the need for manual carrying. The initial belt was around 80 meters long (two loops of 40m each), much like those used at airports.

“It already saved us time and accelerated the process, but it also created pressure on the workers at the exits. They had to track every package and pick out the ones for their region. At first, it was manageable, but when a dozen parcels came through at once, it got hectic.”

The conveyor did bring speed, but it also introduced new operational bottlenecks. That’s when the team began looking for a more intelligent, automated solution.

When shoe sorters entered the picture

The conveyor introduced a structured process, but exceptions began to surface: non-conveyable parcels, i.e. parcels that can't go on the belt and require special handling, consuming extra time and resources.

“A lamp is the best example. It’s not heavy or tall, but you can’t place it flat on the conveyor or stack it neatly on a pallet. It ends up on top of everything in the truck. And then, instead of unloading a truck in 45 minutes, you first have to remove all the top-loaded odd items, and only then get to the pallets.”

That realization led to two questions — what percentage of parcels are “non-standard” and how much are they costing the D Express team in time and labor?‍

“If 5% of parcels require special handling, and we find they take as much time as 20% of standard parcels, then we know they cost disproportionately more. That’s how we started calculating special handling costs.”

For full automation, the team looked for something proven, reliable, and scalable, and so chose a shoe sorter.

“We went with a manufacturer that already had thousands of installations worldwide. We were confident enough in their system that we didn’t even need to test it.”

The investment wasn’t small, but the returns were clear: sorting capacity jumped to 5,000 parcels per hour, error rates dropped, and staffing levels stayed the same, even as parcel volumes rose.

This is an excerpt from the 3rd edition of the First-Hand Last-Mile newsletter. To continue reading, please subscribe.