ITMS
ITMS: BBTech's inventory management system, from an Excel workflow to a web application
An inventory system that evolved from an operational Excel stock tracker into a web application: I developed the advanced Excel logic, contributed maintenance fixes, merged direct label printing, and conducted the hardware-identity audit.
BBTech's inventory management system for its refurbished-laptop operation, and how it evolved. It began as the BBTech Stock Tracker, an Excel workbook I worked on and maintained: live from July 2025 and developed through a versioned change log, with automatic barcode and group SKUs, a receiving-to-sold pipeline across hardware, software, quality-check and e-commerce stages, VBA macros that log every status change with its time and author, and a written user guide. The team ran the operation on it and submitted it weekly. When BBTech moved the workflow into a web application in 2026, another BBTech developer built it while I was committed to other projects. Since its release I troubleshoot, fix and improve it with the developer. Label printing, already part of the Excel workflow, became a problem I was asked to solve: I built the RPOMS Print Engine independently and am integrating it with ITMS.
Excel formulas and VBA automation; Print Engine direct integration; drawer UI and CSV export; hardware-identity architecture audit
Key Highlights & Practical Impact
Executive Scan- Enhanced the historical BBTech Stock Tracker (Excel): dynamic Group SKU formulas with LET and TEXTJOIN, duplicate barcode validation, and VBA QC transition logs
- The Excel workflow's stage concepts (receiving, hardware, QC, e-commerce, warranty) established the baseline for the later web application
- Merged direct label printing and CSV export into production on main (commit 0f67de6), connecting ITMS to the standalone Print Engine
- Resolved UI defects in the device drawer footer actions and sale timestamp presentation
- Conducted the hardware-identity audit: exposed how generated sequential stock tags (HP1) concealed duplicate refurbishments, establishing the need for SMBIOS hardware binding
Ready to explore the build?
A detailed look at the end-to-end architecture, process workflows, key engineering decisions, live production capabilities, challenges, and results.
This system is proprietary commercial software. Information presented here is scoped for public review without disclosing internal credentials or customer records.
Writing from this work
Why Hardware Identity Matters: How Generated Stock Prefixes Concealed Duplicate Refurbishments in ITMS
An architectural audit of enterprise refurbishment systems: why generating sequential stock prefixes like 'HP1' creates phantom inventory, and how binding to immutable SMBIOS hardware serials provides a tamper-proof audit trail.
Versioning an Operational Spreadsheet Like Software
A stock tracker's Change History sheet as a release log: eight iterations before go-live, a 1.x line after, user-requested versions, and what an in-file changelog cannot give you.
Why My VBA Maps Columns by Header Name, Not Column Number
One workbook held both approaches: event macros with hard-coded column numbers that drifted as columns were added, and an update macro that finds columns by header text. The difference.
Modelling a Multi-Stage Refurbishment Pipeline in Excel
Following one laptop through an Excel stock tracker: a completeness gate at receiving, an automatic hand-off list, status derived from department ticks, e-commerce counts, and EDATE warranties.
What Survives When an Excel Tracker Becomes a Web App
Mapping an Excel stock tracker's sheets, formulas and macros onto the tables of the web system that replaced it: what carried over unchanged, and what had to become explicit.
Writing a User Guide Into the Spreadsheet Itself
A stock tracker's in-workbook guide: a colour legend for formula, drop-down and free-text columns, a sheet-by-sheet purpose list, and how the guide drifted from the formulas it described.
Dependent Drop-Downs With INDIRECT and Named Ranges, and What They Cost to Maintain
A Brand → Model drop-down built with INDIRECT and one named range per brand works well on day one. The two update procedures, orphaned #REF! names and fixed ranges are what it costs later.
Letting Another Web App Print Through an Open Tab: BroadcastChannel, Web Locks and COOP
How a tiny relay page lets another web application print on a Bluetooth printer held by an already-open tab, with one tab answering via a Web Lock and the printer's real result reported back.
Maintaining a Web System I Didn't Build: Small, Scoped Fixes
Three small fixes to a Next.js inventory app another developer built: a lazily loaded Excel library, a duplicate fetch on first load, and a reset-password redirect, kept reviewable.
Chrome Throttled My Bluetooth Printer: Moving Timers Into a Web Worker
Labels slowed from about 4 seconds to 13 or more whenever the print tab was in the background. The cause was Chrome's timer throttling; the fix was a tiny Web Worker that owns the waits.
Adding Label Printing to an Existing Next.js App Without Touching the Printer
The calling side of a print integration: validating SKUs the way the printer app will, passing them in a URL fragment, detecting blocked pop-ups, and refusing to print unsaved changes.
Logging Every Status Change in Excel With VBA to Measure Time per Department
Formula-driven status changes don't fire Worksheet_Change. How a stock tracker logged them with Worksheet_Calculate, timed each stage, and read the log back with SUMIFS and LOOKUP(2,1/…).
Generating Barcode and Group SKUs in Excel From Spec Columns
How an Excel stock tracker built a per-brand serial that rolls past 99, a barcode SKU and a variant group key from spec columns with LET and TEXTJOIN, and where formula IDs break.