Solution
POS Software Development
Offline-first checkout, card processing, and inventory sync built for retailers and restaurants outgrowing an off-the-shelf terminal.
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A point-of-sale system fails at the worst possible moment: mid-transaction, when the internet connection drops and a customer is standing at the counter with a full cart. POS software development mostly comes down to designing for that moment from the start, so a sale completes and syncs later, rather than treating a lost connection as an edge case that gets patched in after launch.
We build POS systems for retailers and restaurants whose transaction volume or inventory complexity has outgrown Toast, Square, or Lightspeed, or whose data needs to integrate directly with a proprietary inventory or ERP system those platforms were never built to reach. Card processing routes through a terminal SDK from Stripe Terminal or Adyen, so card data never touches the business's own servers, which keeps most of the system out of PCI DSS scope entirely.
Scope
Core features
Offline-first sales processing
Transactions complete and queue locally when connectivity drops, syncing automatically once the connection returns, so a lost signal never stops a sale at the counter.
Card payment processing
Tap, chip, and swipe through a terminal SDK such as Stripe Terminal or Adyen, keeping raw card data off the business's own servers.
Real-time inventory sync
Stock levels update across every register and location the moment an item sells, rather than at end of day.
Receipt generation
Printed, emailed, or texted receipts, generated the same way regardless of whether the transaction was processed offline or online.
Multi-jurisdiction tax calculation
Tax rates and exemptions apply correctly across states or countries for businesses selling in more than one jurisdiction.
Split payments and multiple tender types
Cash, card, and gift card combined on a single transaction without the register losing track of what is still owed.
Employee permissions and shift management
Cashier-level permissions and shift tracking tied to who actually processed each transaction.
Discounts and promotions at checkout
Pricing rules apply automatically at the register rather than requiring a manager override for every promotional sale.
Returns and exchanges
Tied back to the original transaction record, so a return updates inventory and the original sale's history correctly rather than creating an orphaned record.
Architecture
Decisions that shape the build
Offline-first architecture and conflict handling
A local transaction queue needs a clear rule for what happens when the same inventory item sells on two offline terminals before either syncs, so the system resolves the conflict explicitly rather than silently overselling stock.
PCI DSS scope reduction through terminal SDKs
Routing card data through a terminal SDK like Stripe Terminal or Adyen, rather than capturing it in the business's own software, keeps most of the POS system outside PCI DSS scope and usually qualifies the business for a simpler self-assessment questionnaire.
Hardware selection and compatibility
Card readers, receipt printers, and barcode scanners vary in what they support out of the box, and the choice of payment terminal SDK often narrows which hardware options are actually compatible.
Real-time inventory sync across locations
Selling the same item from stock shared across locations needs inventory updates fast enough that two registers don't both sell the last unit, particularly during a busy period when sync delays matter most.
Multi-jurisdiction tax rules
Businesses selling across state or country lines need tax rates and exemption rules that apply automatically per transaction, rather than a single fixed rate that only works for one location.
Build vs buy
When to build and when to buy
Toast, Square, and Lightspeed cover standard retail and restaurant checkout well, and their per-terminal or per-transaction pricing usually makes sense for a single-location or standard multi-location business without unusual integration needs.
Custom development is worth it when the POS needs to integrate tightly with a proprietary inventory or ERP system those platforms cannot reach, when transaction volume makes per-transaction fees expensive at scale, or when a business is building POS software as its own product.
Delivery
How delivery is phased
Map transaction flows and integration points
We document how sales, returns, and inventory actually move today, along with which payment processor and inventory or ERP system the POS needs to connect to.
Build the offline-first transaction engine
The core transaction queue and payment terminal integration get built and tested against real connectivity loss, since offline reliability is the foundation everything else depends on.
Build inventory sync, tax, and reporting
Real-time inventory sync, multi-jurisdiction tax rules, and reporting get layered on next. This typically takes several weeks depending on how many locations and integrations are involved.
Pilot on a subset of terminals and launch
A portion of registers or locations runs on the new system before a full rollout, since edge cases in offline sync and tax rules surface faster under real transaction volume.
Technology
Typical stack
FAQ
POS System Development FAQs
How does offline-first POS handle a transaction with no internet connection?
The sale completes and stores locally on the device, then syncs to the central system automatically once connectivity returns. Inventory and reporting reflect the transaction the moment it happened, not the moment it synced, with conflict handling for anything that changed on both sides in the meantime.
Can a custom POS reduce our PCI DSS compliance scope?
Yes. Routing card data through a terminal SDK like Stripe Terminal or Adyen, rather than capturing it in your own software, keeps most of the system outside PCI DSS scope and typically qualifies the business for a simpler self-assessment questionnaire.
Should we use Stripe Terminal or Adyen for card payments?
Both route card data away from your own servers and reduce PCI DSS scope similarly. The better fit usually comes down to which regions and card networks the business needs to support and which one integrates more directly with the payment processor already handling online sales.
Can inventory sync in real time across multiple store locations?
Yes. Stock levels update the moment an item sells at any register or location, which matters most for businesses selling from shared stock across a small footprint of locations where overselling the last unit is a real risk.
Should we build custom POS or use Toast or Square?
Toast and Square cover standard retail and restaurant checkout well and are usually the faster, cheaper option. Custom development makes sense when the POS needs to integrate tightly with a proprietary inventory or ERP system, or when transaction volume makes per-transaction platform fees expensive at scale.
Services
Services involved
- Custom Software DevelopmentWe build software around the processes your business already runs on, so operations stop depending on spreadsheets, workarounds and tools that were never built for your workflow.
- Backend DevelopmentWe build the server-side systems underneath your product: data models, business logic, queues and the infrastructure that keeps them fast under load.
- API DevelopmentWe design, build, document and version REST and GraphQL APIs that partners can integrate against without calling your engineers first.
- Mobile App DevelopmentWe build native and cross-platform mobile apps, handle App Store and Play Store submission, and design for the offline gaps and device permissions a phone actually has to deal with.
By industry
POS System Development built for specific industries
- Restaurant POS SoftwareFloor plan, course timing, and tip distribution built into the POS itself, not tracked on a whiteboard next to the register.
- Retail POS Software DevelopmentA register that knows about the online order, the loyalty balance, and the return policy, not just the item in the customer's hand.
Industries
Industries that commission this
Insights
Planning guides
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