The five things that actually matter
Most inventory platform comparisons compare feature lists. That's the wrong starting point — every serious platform checks 80% of the boxes. What separates a good fit from a costly migration in 18 months is five things, in this priority order:
1. Stock sync latency (non-negotiable)
How long does it take for a sale on eBay to reduce stock on Amazon? On TikTok Shop? On your website? If the answer is anything above 60 seconds, you will oversell during peak periods. Oversell penalties on eBay and Amazon damage account health, which costs more than any software saves.
Ask every vendor:“What's your 95th percentile stock sync latency across channels, measured end-to-end, not just API round-trip time?” If they don't measure it, walk away.
2. Three-year total cost
Month-one pricing is misleading. Calculate what you'll pay over three years at your projected growth, including:
- Per-user fees as your team grows
- Order volume tier upgrades
- Per-order overage charges
- Implementation and migration fees
- Custom integration charges for couriers or marketplaces
- Annual price increases (ask explicitly — most platforms raise 5-10%/year)
Platforms with per-order overage (like MaxInvent's 10p/order) are easier to model than per-user models because your team size is less predictable than your order volume.
3. Courier integrations for your actual carriers
“We integrate with 50+ couriers” sounds impressive. What matters is whether your couriers — Evri, Royal Mail, DPD, Amazon Shipping, Temu if relevant — are native integrations or third-party bridges. Native means the platform fetches rates, buys labels, and tracks parcels directly. Bridge integrations break when APIs change and cost you hours per month.
Specific test: ask for a live demo of buying a shipping label for each of your top 3 couriers. Not a screenshot — a live demo.
4. Data residency and support hours
If you handle B2B customers with data processing agreements, or regulated products (health, children's, age-gated), UK or EU data residency matters legally. For everyone else it's a nice-to-have. UK-based support during UK working hours matters more day-to-day — a 4-hour response from a US vendor when you're dispatching in the UK afternoon is painful.
5. Migration effort (the hidden cost)
A platform that takes 4 weeks to migrate to, but fits perfectly, beats a platform you can switch on overnight that's 80% fit. Migration cost is usually 20-40 hours of your team's time. Factor that into the decision — if the new platform only saves you £200/month, the migration needs to pay back within 6 months or it's not worth it.
The checklist most buyers skip
Before you commit to any platform, confirm these ten things in writing:
- Stock sync latency SLA (target: under 60 seconds, 95th percentile)
- What happens when a marketplace API is down — queue or drop?
- Full pricing at your projected volume, with no discounts applied
- Migration support included vs billable
- Data export format and ease of leaving
- Support response SLA on the plan you're buying
- List of current UK customers willing to take reference calls
- Roadmap commitments for the integrations you need
- Data residency (physical hosting location)
- Uptime SLA and how incidents are communicated
Red flags that should kill a shortlist candidate
- No published pricing page
- Annual contract required before any trial access
- Sales team won't put you in touch with an existing customer
- “Custom integration” quoted for any of your top-3 couriers
- Implementation fee above £3,000 without line-item breakdown
- Support only via email ticketing, no phone or chat
- No incident status page
How we'd run the process
- Week 1: Shortlist 3-4 platforms using publicly available info. Read 20+ reviews on G2, Capterra and Trustpilot for each.
- Week 2: Demo each shortlisted platform. Do not accept scripted demos — insist on entering your own data and doing the workflow you do 100 times a day.
- Week 3-6: Run a real-data trial on the top 1-2 platforms. Flow at least 2 of your channels through each. Track dispatch throughput, error rates, and support response time.
- Week 7: Negotiate. Get a reference call with 2 existing UK customers. Read the contract — the cancellation clause especially.
- Week 8: Sign. Plan the migration for the following 4-6 weeks using the playbook at our migration guide.