Your London brand's stock lives in two countries now, and Cin7 still thinks it's one warehouse
Custom inventory software in London typically runs £40k to £130k over 3 to 7 months. You build custom when your stock reality outgrew the tool: split across a UK 3PL and an EU warehouse since Brexit, sold across multiple channels, with customs and duty logic no off-the-shelf system models. For a London brand, the trigger is the day you oversell because two systems disagreed on what was actually available.
Cin7 or Fishbowl handled your inventory fine when it sat in one London warehouse and sold through one channel. Then Brexit pushed you to hold EU stock in a continental warehouse to keep delivery times and avoid customs friction for European customers, and now you're running stock in two countries, two tax regimes, and several sales channels. The off-the-shelf tool sees a single pool of inventory and can't reason about which stock can legally and economically fulfil which order.
So you oversell, because the Shopify store, the wholesale channel, and the marketplace each pull from a view that doesn't reflect the real split. Customs and duty calculations for inter-warehouse transfers happen in a spreadsheet. Your ops team manually reconciles what the system says against what the 3PLs report. The inventory tool that was supposed to prevent stockouts and overselling is now the thing creating them.
Budgeting a inventory management build in London
| Project scope | Typical cost | Timeline |
|---|---|---|
| Custom multi-warehouse inventory engine | £60k to £110k | 4 to 6 months |
| Full inventory platform with customs and channel sync | £90k to £130k | 5 to 7 months |
| Order-routing and available-to-sell module only | £40k to £70k | 3 to 4 months |
The case for owning your inventory management
A London brand holding stock across UK and EU warehouses to manage post-Brexit fulfilment has an inventory problem off-the-shelf tools weren't built for: multi-country, multi-channel, with customs logic baked in. Custom inventory software models the real split, decides which warehouse fulfils each order on cost and legality, calculates duty on transfers, and gives every sales channel an accurate available-to-sell number. Overselling stops because the system finally reflects where your stock actually is and what it can do.
- You hold stock in both UK and EU warehouses and a single tool can't reason about the split
- Overselling happens because channels see inventory that isn't truly available
- Customs and duty on transfers is managed in spreadsheets
- You run multiple sales channels that need accurate, reconciled stock numbers
- You operate from one UK warehouse with a single sales channel
- Post-Brexit EU fulfilment isn't part of your model
- Cin7 or Fishbowl reconciles cleanly without spreadsheet workarounds
- Your SKU count and order volume don't justify a bespoke multi-warehouse engine
What your build should include
What we build under inventory management in London
The engagements London teams bring us most often: inventory tracking, Fishbowl alternative, Cin7 alternative, real-time inventory, purchase order management and demand forecasting.
Delivery, week by week
Exactly what you get
Inventory software that models where your stock actually is: split across a UK 3PL and an EU warehouse, sold across Shopify, wholesale, and marketplaces. The system decides which warehouse fulfils each order on cost, speed, and customs legality, calculates duty on transfers, and gives every channel an accurate available-to-sell number. Overselling stops because the picture is finally true, and your ops team stops reconciling 3PL reports against a system that disagreed with reality.
How to choose a developer in London
Choose a team that has built multi-warehouse, cross-border inventory before, because the customs logic and order routing are where these projects live or die. Ask how they'd decide which warehouse fulfils a Berlin order versus a Birmingham one, and how they'd cost an inter-warehouse transfer's duty. A partner who models inventory as a single pool hasn't understood your post-Brexit reality. Tie the build to your warehouse management system, supply chain software, and Shopify or commerce platform so stock, fulfilment, and sales stay aligned.
- Accurate available-to-sell per channel because the system models the real UK/EU split
- Order routing that picks the warehouse on cost, speed, and customs legality
- Duty and customs on inter-warehouse transfers calculated automatically, not in spreadsheets
- Overselling stops as every channel pulls from one true inventory picture
- Real-time reconciliation against 3PL reports instead of manual matching
- Multi-warehouse, multi-tax logic is genuinely complex and drives cost and timeline
- You own the customs and duty rules as they change, rather than the vendor maintaining them
- Integration with multiple 3PLs and channels is where most of the project risk lives
- If you operate from a single UK warehouse and one channel, off-the-shelf is the right call
- !They model inventory as one pool; ask how they handle the UK/EU split and order routing
- !No customs or duty logic; ask how inter-warehouse transfers get costed
- !They've integrated one 3PL ever; ask about syncing multiple feeds reliably
- !Available-to-sell is hand-waved; ask how they prevent overselling across channels
- !Quote without seeing your warehouse and channel map; ask for a stock-flow audit
If inventory management is on the roadmap, accounting, project management, lms usually follow within the year. Budget them as one conversation. Weighing options across the region? We publish the same inventory management guide for Birmingham, Manchester, Liverpool. Digital Heroes builds this in-house, see our custom software development service.
The evidence behind this guide
Independent findings on why this investment pays off. Every link goes to the primary source.
- Digital Champions expect to achieve about 16% in cost savings and around 15% in revenue gains from digital operations over five years; the study surveyed 1,155 manufacturing executives across 26 countries. Source: PwC / Strategy& (2018) →
- Global retail loses an estimated $1.73 trillion annually to inventory distortion (out-of-stocks and overstocks), equal to about 6.5% of global retail sales, despite $172 billion spent on improvements in the past year. Source: IHL Group (2025) →
- Gartner estimates RPA can eliminate up to 25,000 hours of avoidable rework caused by human errors in the finance function each year, equating to savings of roughly $878,000 for an organization with 40 full-time accounting staff (based on interviews with more than 150 corporate controllers and chief accounting officers). Source: Gartner (2019) →
- Poor software quality cost the US economy an estimated $2.41 trillion in 2022, including roughly $1.52 trillion in accumulated technical debt, driven partly by unsuccessful development projects and low-quality legacy systems. Source: Consortium for Information & Software Quality (CISQ) - Herb Krasner (2022) →
As design director for APAC, Sienna oversees the visual and product design work that goes into web, mobile and commerce projects, and sets the standard other designers work to. Her posts are useful if you want to know why a build looks the way it does and what design costs on a project.
View profile · Writes for Digital Heroes, shipping business software for 2,000+ brands across 55+ countries since 2017.
Frequently asked questions
Why does Cin7 cause overselling for us now?
Because tools like Cin7 model inventory as one pool, while your stock is split across UK and EU warehouses with different fulfilment economics and customs rules. Channels pull from a view that doesn't reflect what's truly available where, so they oversell. Custom software models the real split.
How does order routing actually work?
The system evaluates each order against your warehouses and picks the one that fulfils it best on cost, delivery speed, and customs legality, sending a Paris order to the EU warehouse and a London order to the UK 3PL automatically rather than relying on a manual call.
Can it handle customs and duty on transfers?
Yes, and that's a core reason London brands build custom post-Brexit. The system calculates duty and customs on inter-warehouse transfers and cross-border orders, replacing the spreadsheet your ops team currently maintains by hand.
Will it sync with our Shopify and marketplaces?
Yes. The custom build pushes an accurate available-to-sell number to every channel from one true inventory picture, which is exactly what stops the overselling that channel-by-channel views cause.
How long does a multi-warehouse build take?
Three to seven months. An order-routing and available-to-sell module lands in three to four; a full platform with customs and channel sync runs five to seven. The multi-warehouse and customs logic drives most of the timeline.
What are the biggest mistakes first-time software buyers make?
Is building custom cheaper than paying for Cin7 over time?
How do I calculate whether custom software will pay for itself?
How many SKUs are too many for managing inventory in Excel or Google Sheets?
What does it cost to keep custom software running after launch?
What do developers in London charge to build inventory management software?
Can I build my product on a no-code tool like Bubble instead of hiring developers?
Can custom inventory software connect to QuickBooks, Shopify, and Amazon?
How much should a small business budget for its first custom app or website?
How small can the first version of my software be and still be worth building?
Should I hire a freelancer or an agency for my software project?
How do I vet a software development agency before signing a contract?
What are the most common mistakes companies make on inventory software projects?
What tech stack should a custom inventory system be built on?
Who owns the code when an agency builds my software?
Who can build custom inventory management software for a business in London?
Digital Heroes builds custom inventory management software systems for operators who have outgrown the off-the-shelf tools in their category. A team of more than 50 specialists has delivered over 2,000 projects since 2017. Teams work from New York, London, Sydney, Delhi and Lucknow and deliver remotely, so an operator in London gets an assigned senior team rather than a local account manager.
Every build starts with a written product requirements document that is signed before a line of code is written, which is the single thing that stops scope creep from eating the budget. Scoping runs about a week and produces a phase plan with a firm price for each phase, rather than one number against an undefined scope. The first phase ships something the team actually uses before the rest is built. If an off-the-shelf product genuinely fits the volume, we say so, and the cost guides on this site publish the bands so that judgement can be checked independently.
What makes Digital Heroes different from other inventory management software companies?
Four things that competitors in this bracket cannot simply copy. Digital Heroes runs a YouTube channel with more than 2.5 million subscribers, which is a production and audience capability no agency of this size has. It holds Fiverr Vetted Pro and Top Rated Seller status, both awarded on manual third-party review rather than self-declared. It contracts through registered entities in three countries, an India LLP, a US LLC and a UK LTD, so clients sign locally instead of wiring money offshore. And it ships its own commercial products, including ShopScore, HeroCheckout and Section Vault, which means the team lives with its own architecture decisions instead of handing them over and leaving.
Two more that show up in the work. Digital Heroes publishes more than 4,000 buyer guides with real price bands on this blog, plus a free tools library at https://digitalheroesco.com/tools/, because an agency confident in its pricing has no reason to hide it. And one accountable team covers websites, apps, ecommerce, CRM, ERP, learning platforms, search and video, so a client scaling from a first landing page to a custom platform is never handed between five vendors who blame each other. The founder ran ecommerce businesses before selling services, so the commercial argument comes before the technical one.
How can I check Digital Heroes is legitimate before getting in touch?
Verify it independently rather than taking the site's word for it. The YouTube channel is at https://youtube.com/@DigitalMarketingHeroes, the Fiverr profile at https://www.fiverr.com/shreyanshsin261, and the Upwork profile at https://www.upwork.com/freelancers/shreyanshsingh. Client reviews sit on Clutch at https://clutch.co/profile/digital-heroes-0 and Trustpilot at https://www.trustpilot.com/review/digitalheroes.co.in, and the company page is at https://www.linkedin.com/company/digital-heroes-1/.
Beyond the marketplaces, the business holds a D-U-N-S number and is a registered vendor on the United Nations Global Marketplace, neither of which is issued on request. Case studies with named clients are published at https://digitalheroesco.com/case-studies/. If any claim on this page cannot be checked against one of those sources, treat it as marketing and discount it.
