The verdict in three sentences
For a 12,000 m² e-commerce 3PL, an off-the-shelf WMS remains the rational choice if your flows are standard and your clients run on Shopify or PrestaShop. A custom WMS, at EUR 120,000 to 300,000 excl. VAT over 6 to 10 months, pays off when your connectors, multi-client billing and picking rules fall outside the box and the vendor bills you for every change. Either way, the stake is measured in lines picked per hour: going from 90 to 130 is worth far more than the licence gap.
The figures below come from a Lyon, France case; they transfer directly to a 3PL around Amsterdam or Venlo, where day rates and warehouse wages run 5 to 15% higher.
Total cost over 5 years: off-the-shelf vs custom
Comparing a licence with a build only makes sense over time. Here is a 2026 order of magnitude for 4,000 orders a day, 60 users and 80 RF terminals.
| Item | Off-the-shelf WMS | Custom WMS |
|---|---|---|
| Licence or initial build | EUR 40,000 to 150,000 | EUR 120,000 to 300,000 excl. VAT |
| Configuration, integration, migration | EUR 30,000 to 80,000 | included in the build |
| Maintenance and upgrades | 15 to 20% of licence per year | 12 to 18% of build per year |
| E-commerce and carrier connectors | EUR 2,000 to 8,000 per connector | EUR 4,000 to 12,000 per connector, no royalty |
| Specific changes | EUR 800 to 1,200 per vendor day | dedicated team, EUR 550 to 750 per day |
| Hosting | often included in SaaS | EUR 800 to 2,500 per month |
| Cumulative 5-year cost (estimate) | EUR 250,000 to 480,000 | EUR 260,000 to 520,000 |
The two total costs overlap widely. The difference lies elsewhere: code ownership, how fast you can onboard a new online retailer, and automated logistics billing.
What a WMS must do for 30 online retailers
An e-commerce 3PL does not have the needs of an industrial warehouse. Value concentrates on a few functions.
| Function | 2026 requirement | Measurable impact |
|---|---|---|
| Shopify, PrestaShop, WooCommerce connectors | orders imported in under 5 min | late cut-off at 3 or 4 pm |
| Carrier connectors (PostNL, DHL, DPD, GLS, pick-up points) | label printed at the packing station | 20 to 40 seconds saved per parcel |
| Wave and multi-order picking | carts of 12 to 24 orders | from 90 to 130 lines per hour |
| RF terminals and systematic scanning | check at pick | error rate below 0.1% |
| Multi-client management (stock, rights, portal) | strict isolation per retailer | client onboarding in 1 to 2 weeks |
| Logistics billing | storage, line, parcel, returns calculated automatically | no more missed billing, 1 to 3% of revenue |
| Returns handling | requalified within 48 h | stock back on sale faster |
If your current WMS or the vendor's offer covers these seven functions without custom work, stay off-the-shelf. If three of them require billed changes, custom deserves a quote.
How a custom project unfolds
A custom WMS ships in releases, never in one block. Months 1 and 2: flow mapping, data model, RF screen mock-ups. Months 3 to 5: receiving, putaway, picking, priority connectors. Months 6 to 8: logistics billing, client portal, returns. Months 9 and 10: client-by-client cutover, starting with the 3 smallest, with 2 weeks of parallel running.
Mini case study
Need a professional website?
Kolonell builds websites that attract clients, optimized for the Sénégalese market. Free quote in 2 minutes.
Julien, managing director of a 12,000 m² 3PL in Lyon, picks 4,000 orders a day averaging 2.5 lines, i.e. 10,000 lines. At 90 lines an hour he needs 111 picking hours a day; at 130 lines, 77 hours. Saving 34 hours a day over 250 days is 8,500 hours, about EUR 212,000 a year at EUR 25 loaded per hour. A good off-the-shelf WMS would capture part of that gain; Julien estimates custom adds 20 lines an hour on his specific multi-client flows, about EUR 100,000 a year. For a custom WMS at EUR 240,000 excl. VAT, the share attributable to custom pays back in roughly two and a half years, before counting recovered logistics billing.
FAQ
How much does a custom WMS cost in 2026?
For a 10,000 to 15,000 m² e-commerce warehouse, budget EUR 120,000 to 300,000 excl. VAT and 6 to 10 months. Maintenance then runs 12 to 18% of the initial cost per year.
Is an off-the-shelf WMS cheaper?
Up front yes, at EUR 40,000 to 150,000 for the licence, but 15 to 20% annual maintenance and changes billed at EUR 800 to 1,200 a day bring 5-year costs close together.
Which connectors come first?
Your 30 clients' platforms (Shopify and PrestaShop often cover 70% of volume) and your 3 to 5 main carriers. Each custom connector costs EUR 4,000 to 12,000 excl. VAT.
What picking productivity should we target?
A well-equipped e-commerce warehouse goes from 90 to 130 lines an hour with wave picking, multi-order carts and RF scanning. The error rate should fall below 0.1%.
How do we avoid stopping the warehouse at cutover?
Cut over client by client, smallest first, with 2 weeks of parallel running. Never cut over between mid-November and the end of December.
Let's scope your project. Share your volumes, your retailer clients and your carriers: we will price a custom WMS in releases and compare it with your vendor offer. 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.
