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FIG 01 · Inventory Management Software

Custom inventory management software built around your stock

Multi-location stock, barcodes, lot and serial tracking, reorder rules and POS for retailers, wholesalers, D2C brands and small manufacturers outgrowing spreadsheets.

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Stock controller scanning a carton, with stock levels updating on a tablet

FIG 02 · Quick answer

What is custom inventory management software?

Custom inventory management software tracks what you hold, where it is and when to reorder, built around your own products and processes. Elgrith develops inventory systems with multi-location stock, barcode and GTIN scanning, lot and serial tracking and reorder rules, synced with Shopify, Square or Lightspeed POS and your accounting or ERP.

Receiving, counts, sales and accounting from one stock record
Shelf → ledger
Projects delivered since 2015
1,000+
Clients across the USA, UK and India
250+
Your code, repository and IP
100%

FIG 03 · Why it matters

Stock is money sitting still. Seeing it is the job.

The numbers behind stock visibility, from the US Census Bureau’s August 2026 inventories release (15 Oct 2026) and FRED, read on 23 Oct 2026. Next Census release: 17 Nov 2026.

FIG 04 · Decide

Build, buy or extend?

Custom isn’t always the answer. Off-the-shelf tools like inFlow, Cin7 or Zoho Inventory, or an ERP like Odoo, are right for many businesses. This is how we compare the routes with you, before any quote.

Buy an inventory app vs extend an ERP vs build custom inventory software
Buy (inFlow, Cin7, Zoho Inventory or similar)Extend an ERP (Odoo or similar)Build custom
Best forStandard stock flows and one or two sales channelsBusinesses already running that ERP for financeUnusual products, rules or channels that tools fight
Fit to your processYou adapt to the productGood, within the ERP’s data modelBuilt around your stock and your people
Ongoing cost shapeSubscription per user, location or order volumeERP licence plus customisationBuild cost, then hosting and support you control
Code and dataThe vendor’s product; your data under their termsYour customisations; the ERP stays the vendor’sYours
Main riskWorkarounds in spreadsheets when you outgrow itUpgrades breaking heavy customisationRebuilding what a tool already does well

We often extend instead of replace: a custom app for receiving, counts or POS that syncs to the tool or ERP you already pay for.

Comparing subscription prices? Inventory software cost guide

FIG 05 · What you get

What custom inventory software does

Inventory management software development starts with one item master and one stock ledger. Every count, sale, transfer and return is a movement against it, so you can always say how a number got there.

Shelves of labelled cartons, one sealed with blue tape, behind a barcode scanner and a stock tablet
Inventory Management Software Development · built in-house

01

Item master

Products, variants, units of measure, GTINs and your own SKUs, with supplier codes and pack sizes in one place.

02

Locations and bins

Stores, stockrooms, vans and bins as locations, with stock by location and an audit trail for every movement.

03

Receiving and transfers

Goods received against purchase orders, discrepancies flagged, and transfers between locations tracked in transit.

04

Cycle counts

Rolling counts by zone, category or value, with variances approved before they touch the ledger.

05

FIFO, FEFO, lot and serial

First-in-first-out or first-expired-first-out picking, lot and expiry dates, and serial numbers from receipt to sale.

06

Reorder points and safety stock

Reorder rules by item and location from sales history and lead times, with draft purchase orders ready to approve.

07

Returns

Returns graded and put back to stock, quarantine or write-off, with the reason recorded for reporting.

08

Reporting

Stock value, ageing, sell-through, dead stock and shrinkage by location, from your own data.

Deliverables

11

deliverables, in writing

Included in every build, written into your fixed quote before work starts.

FIG 06 · Integrations

Integrations with your store, POS and books

Inventory software is only as good as its sync. We integrate through each platform’s published APIs, using your accounts and access, and pin the API version we build against. We claim no partner status with Shopify, Square, Lightspeed or any other vendor.

  • Online store
  • POS
  • Marketplaces
  • Accounting
  • ERP
  • Suppliers

  • Shopify

    API
    Shopify Admin GraphQL API; 2026-10 is the latest stable version, released 1 Oct 2026 (Shopify docs, checked 23 Oct 2026)
    Data
    Products, inventory levels by location, orders, refunds and webhooks
    E-commerce Development

  • Square

    API
    Square Inventory and Catalog APIs; the latest API version listed is 2026-09-16 (Square changelog, checked 23 Oct 2026)
    Data
    Catalog items, stock counts and adjustments, and in-store sales

  • Lightspeed Retail (X-Series)

    API
    Lightspeed’s published Retail API, using your account’s access
    Data
    Products, outlets, stock levels and sales

  • Accounting

    Data
    Stock value, cost of goods sold, purchase bills and end-of-day sales
    Where
    Xero, QuickBooks, Sage or your accounting system’s API
    Accounting Software Integration

  • ERP

    Data
    Items, purchase orders and stock movements in both directions
    Where
    Your ERP’s published APIs
    ERP Development

  • Warehouse operations

    When
    Pick, pack, waves and dock scheduling across a real warehouse
    Where
    That is logistics software; your inventory core feeds it
    Logistics Software Development

FIG 07 · Identifiers

Barcodes, GTINs and RFID

Get identifiers right and every sync gets easier. GS1 US says GTINs are issued only by GS1 and are 8, 12, 13 or 14 digits long. Your SKU is yours. We store both. We claim no GS1 membership on your behalf: you license your own company prefix.

04principles

  • GTIN vs SKU

    The GTIN identifies the product to the world and marketplaces; your SKU is your internal code. Both live on the item master.

  • GS1 barcodes

    UPC-A and EAN-13 on retail items, GS1-128 on cartons and pallets with lot and expiry data in the barcode.

  • RFID

    RFID tags for fast counts of whole shelves or cartons, where item value justifies the tag cost.

  • Labels

    Shelf, item and carton labels printed from the system, so codes never get typed by hand.

FIG 08 · Point of sale

Custom POS software development

POS software development is mostly about the bad moments: the internet drops, a card is declined, a till is double-tapped. We design for those first, and keep card data out of your systems so PCI DSS scope stays small.

06principles

  • Offline mode and sync

    Sales keep going when the connection drops, and sync stock and payments in order when it returns.

  • Idempotent transactions

    Every sale carries an idempotency key, so a retry never charges twice or deducts stock twice.

  • Hardware

    Receipt printers, scanners, cash drawers and card readers from your payment provider, chosen with you per store.

  • PCI DSS v4.0.1 scoping

    Hosted payment fields, tokenisation or P2PE readers so card data never touches your POS. Your acquirer confirms your SAQ type.

  • Payments

    Card, wallet and split payments through your provider’s SDK.

    Payment gateway integration

  • Choosing accounting software?

    End-of-day sales post to your books. How the main options compare in 2026.

    Xero vs QuickBooks vs Sage

FIG 09 · Mobile

Mobile scanning apps

Counts, receiving and transfers happen on the shop floor, not at a desk. We build scanning apps for phones and rugged handhelds that keep working offline.

05principles

  • Phone camera scanning

    Fast barcode scanning on everyday phones for small teams and stores.

  • Rugged handhelds

    Apps for handhelds with built-in scanners, for high-volume counts and receiving.

  • Offline counts

    Count a stockroom with no signal, then sync and reconcile when back online.

  • iOS and Android

    Native or cross-platform, chosen on scanner hardware and offline needs.

    App development

  • Budgeting the build?

    What drives the cost of custom software in 2026, item by item.

    Custom software cost guide

Running a warehouse, not a stockroom?

Picking waves and dock doors are a different system.

Warehouse operations, fleet and carrier integrations are our logistics software service. Your inventory core can feed it.

Logistics software development

FIG 10 · Process · 6 steps

Count once, pilot one location, then scale

A free call, a fixed written quote, then sprints with a demo every week: discovery, item and location data cleaned up, a pilot in one store or stockroom, and rollout. You own the code, the data and the IP.

Book a call
  1. Step 01

    Free call

    Tell us what you sell, where you hold it, which channels you sell through and where stock numbers go wrong today.

  2. Step 02

    Discovery

    Your items, locations, stock flows, channels and integrations mapped, including the spreadsheets people really use.

  3. Step 03

    Data model and fixed quote

    One item master and stock ledger, plus a written scope and a fixed quote, before any build starts.

  4. Step 04

    Pilot location

    One store, stockroom or channel built in sprints, with a demo every week and test counts on real stock.

  5. Step 05

    Rollout

    More locations and channels, data migrated from old tools, staff trained and a planned cut-over count.

  6. Step 06

    Support and change

    New channels, API version upgrades and new rules, covered under terms agreed in your written scope.

FIG 11 · What you get

Everything included

Written into your fixed quote, so you know exactly what you are paying for before work starts.

11items

  • Written scope and fixed quote
  • Stock flow and integration map
  • Item master and stock ledger data model
  • Inventory web app with locations, counts and reorder rules
  • Shopify, Square, Lightspeed or marketplace sync in scope
  • Accounting or ERP integration
  • Barcode and label printing set-up
  • Mobile scanning app, if in scope
  • Custom POS with payments kept out of PCI scope, if in scope
  • Data migration from your current tools
  • IP assignment: code and data are yours

FIG 12 · Tech & tools

The tools behind the work

Proven, well-supported tools, chosen for your project and set up in accounts your business owns.

  • TypeScript
  • React
  • Next.js
  • Node.js
  • Python
  • PostgreSQL
  • Redis
  • Shopify Admin GraphQL API
  • Square APIs
  • Lightspeed Retail API
  • Webhooks
  • GS1 barcodes
  • Flutter
  • React Native
  • Swift
  • Kotlin

FIG 13 · Who it’s for

Inventory software for businesses that know their stock better than any template.

Retailers, wholesalers, D2C brands and small manufacturers in the US and UK, outgrowing spreadsheets or off-the-shelf tools.

4 audiences

Retailers

One stock number across stores and online.

Multi-store retailers who need stock by location, transfers between shops and a POS that never oversells online.

  • Multi-location stock
  • Store transfers
  • POS and online sync
  • Cycle counts

FIG 14 · Working with us from the USA and UK

Built in New Delhi. Run on your hours.

Every project gets a point of contact in New York or London and an engineering team in New Delhi. Here is how today’s working days line up, live.

Three ways to work together

  1. 01

    Fixed-scope project

    A written scope, one fixed price and a dated plan. Suits websites, apps and MVPs.

  2. 02

    Dedicated team

    Designers and engineers on your roadmap every month, billed monthly.

  3. 03

    White label

    For US and UK agencies: our work, your brand, unbranded deliverables.

Every engagement

  • Fixed quote in USD, GBP or INR after a free 30-minute call
  • NDA before discovery. You own all code, designs and content
  • A working demo every sprint, not status slides
  • Reply within one business day, calls inside your hours
Book a call

Calls on ET or UK hours

FIG 15 · Rules and dates

Inventory and POS rules and versions (checked 23 Oct 2026)

The rules and versions we design inventory and POS software against, checked on 23 Oct 2026 at their publishers’ own pages.

Inventory and POS rules and versions (checked 23 Oct 2026)
Rule or versionWho it affectsDateWhat it means for your software
PCI DSS v4.0.1Any business that stores, processes or transmits card dataPublished Jun 2024; v4.0 retired 31 Dec 2024The current version of the card data security standard; design to keep card data out of scope
PCI DSS future-dated requirementsThe same businessesEffective after 31 Mar 2025 (now in force)Requirements that were best practice until then are now assessed
GS1 GTINBrands selling through retailers and marketplacesCurrent GS1 ruleGTINs come only from GS1, at 8, 12, 13 or 14 digits; store them beside your SKU
Shopify Admin API 2026-10Stores syncing stock with ShopifyReleased 1 Oct 2026; latest stableBuild against a pinned version and plan an upgrade each quarter
Square API 2026-09-16Businesses syncing stock with SquareLatest listed versionPin the version; test changes before upgrading

General guidance from public sources, not legal advice; your counsel confirms what applies to you. Sources: PCI Security Standards Council blog (11 Jun 2024 and 25 Feb 2022), GS1 US, Shopify’s API versioning page and Square’s API changelog. We claim no PCI certification and no GS1 membership.

Making things, not just selling them? Manufacturing software

FAQ

Frequently asked questions

Straight answers about Inventory Management Software Development with Elgrith.

We don’t publish prices, because cost depends on scope: how many locations and channels, lot or serial tracking, which integrations (Shopify, POS, accounting, ERP), whether you need a mobile scanning app or a custom POS, and how much data must move. After a free call you get a written scope and a fixed quote. Our cost guide lists third-party subscription prices for comparison.

FIG 16 · Related

Keep exploring

All services

Free 30-minute call

Know exactly what’s on every shelf.

Tell us where stock numbers go wrong today. After a free call you get a written scope and a fixed quote, starting with one location or one channel.

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