The verdict in three sentences
At 9,000 parcels a day, a shipping aggregator charging EUR 0.08 per label costs about EUR 190,000 a year, far more than integrating carrier APIs directly. Each API takes 3 to 6 development days, but the real work is error monitoring: a label that fails at 5 pm holds up a truck. A well-sequenced project, one carrier at a time, exits the aggregator in 3 to 4 months without stopping shipments.
The calculation that triggers the project
Multi-carrier aggregators are ideal to start with: one API, dozens of carriers. Beyond 2,000 to 3,000 parcels a day, the per-label fee becomes the 3PL's largest IT line.
| Daily volume | Aggregator cost at EUR 0.08 | Annual cost (264 days) | Direct integration worth it |
|---|---|---|---|
| 1,000 parcels | EUR 80 | EUR 21,120 | No |
| 3,000 parcels | EUR 240 | EUR 63,360 | Worth studying |
| 5,000 parcels | EUR 400 | EUR 105,600 | Yes |
| 9,000 parcels | EUR 720 | EUR 190,080 | Yes, priority |
| 15,000 parcels | EUR 1,200 | EUR 316,800 | Yes, urgent |
Some aggregators offer volume tiers down to EUR 0.04 or 0.05, but the cost still stays above EUR 95,000 a year at this volume.
The 8 carriers: integration effort
Not all APIs are equal. Some offer modern REST with a sandbox, others SOAP or imposed label formats (ZPL, PDF), with label certification by the carrier before go-live.
| Carrier | API type | Development days | Watch point |
|---|---|---|---|
| PostNL | REST | 4 to 5 | Label certification, mailbox parcels |
| DHL Parcel Benelux | REST | 3 to 4 | ServicePoint selection |
| DPD Netherlands | SOAP and REST | 4 to 5 | Pickup points, product codes |
| GLS Netherlands | REST | 3 to 4 | End-of-day manifest |
| bpost (Belgium) | REST | 4 to 5 | Belgian address formats |
| UPS | REST OAuth | 4 to 5 | Customs documents outside the EU |
| DHL Express | REST | 4 to 6 | Commercial invoices for export |
| Trunkrs (same-day) | REST | 3 to 4 | Cut-off times and time slots |
| Total | 29 to 38 days |
On top come the carrier selection engine (rules by weight, destination, promised delivery time, cost), unified tracking via webhooks or polling, and the monitoring module.
Error monitoring, the real workload
On 9,000 labels, a 0.5% failure rate means 45 parcels blocked every day: invalid address, inconsistent postcode, carrier API down. The platform must:
- retry failed calls automatically with increasing delays;
- switch to a backup carrier if an API stays down for more than 10 minutes;
- show the dock supervisor the list of failed parcels with the cause and a one-click fix;
- text the IT team when errors exceed 50 per hour.
Budget and timeline in 2026
| Option | 2026 order of magnitude | Timeline |
|---|---|---|
| Current aggregator | EUR 190,000 per year | Immediate |
| Dutch IT consultancy, time and materials | EUR 750 to 1,000 per day, 60 to 90 days | 4 to 6 months |
| Kolonell, medium-complexity application | 4,000,000 to 7,000,000 FCFA (EUR 6,100 to 10,670) | 4 to 5 carriers, basic monitoring |
| Kolonell, complex application | 7,000,000 to 15,000,000+ FCFA (EUR 10,670 to 22,870+) | 8 carriers, rules engine, monitoring |
| Kolonell maintenance | 35,000 / 75,000 / 120,000 FCFA per month (EUR 53 / 114 / 183) | Basic, Standard, Premium |
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API changes imposed by carriers (1 to 3 per year per carrier) and new carriers are quoted separately. The recommended plan migrates the two carriers with the most volume first, often PostNL and DHL Parcel at 60% of parcels, then the rest in pairs.
Mini case study
Pieter, CIO of an e-commerce 3PL near Amsterdam, ships 9,000 parcels a day over 264 working days. His aggregator costs 9,000 x 0.08 x 264 = EUR 190,080 a year. He chooses a complex application at the top of the Kolonell range, about EUR 22,870, with Premium maintenance at EUR 183 a month (EUR 2,196 a year) and EUR 6,000 a year set aside for API changes quoted separately. Year-one cost is about EUR 31,000, a net saving of EUR 159,000 in the first year and payback in under 2 months after full migration.
FAQ
Do we have to renegotiate carrier contracts?
No, rate contracts stay the same; only the technical channel changes. You do need API credentials for each account, which takes 1 to 3 weeks.
What happens when a carrier changes its API?
Carriers usually announce changes 3 to 6 months ahead. Maintenance covers monitoring of those notices, and each adaptation takes 1 to 3 days.
Can we keep the aggregator for small carriers?
Yes, a hybrid set-up is common: the 8 main carriers direct, the rest through the aggregator, which then handles only 3 to 5% of volume.
How do we avoid downtime during migration?
By switching one carrier at a time, first on 10% of parcels for a week, then on 100%. The aggregator stays live as a fallback until the end.
Will our current thermal printers work?
Yes, the 203 or 300 dpi ZPL printers already in place handle the label formats of all 8 carriers.
Let's scope your project. We will define direct integration of your carriers, the selection engine and error monitoring with you, with a gradual 3 to 4 month migration that never stops your shipments. Detailed quote within 48 h. WhatsApp +221 77 596 93 33.
Mohamed Bah
Fondateur, Kolonell
Passionate about digital and entrepreneurship in Africa, Mohamed has been helping Sénégalese businesses with their digital transformation since 2020. Founder of Kolonell, he believes every SME deserves a professional and accessible online présence.
