Verified evidence01
Offline checkout workflow
IndexedDB stores checkout state and queued operations while ERPNext is unavailable
Source · Public GitHub repository
IndexedDBQuasarService Workers
Project archive
Project case study · Full-Stack
Point of Sale (POS)
Offline-first POS client integrated with ERPNext, designed to keep checkout available during connectivity loss and synchronize queued transactions safely after reconnection.
Vue 3QuasarTypeScriptPiniaIndexedDBService WorkersERPNext REST APIsOffline-First Architecture
2026
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Outcome-focused delivery
Designed and implemented an offline-capable retail workflow covering interface behavior, local persistence, synchronization, and ERPNext integration.
Evidence mode · on
Claims come with context
Each outcome shows its source, related capability, and confidence level. Missing operational data stays visibly unavailable.
Supporting context02
Retry-safe synchronization
Queued operations use stable references and controlled retry behavior to reduce repeated ERPNext submissions
Source · Repository implementation and engineering notes
TypeScriptERPNext APIsIdempotency
Supporting context03
Local-first interaction model
Checkout operations use local state before the synchronization process communicates with the backend
Source · Local demonstration environment
Vue 3PiniaOffline-first
Skill → proof
Where each capability shows up
IndexedDBOffline checkout workflow
QuasarOffline checkout workflow
Service WorkersOffline checkout workflow
TypeScriptRetry-safe synchronization
ERPNext APIsRetry-safe synchronization
IdempotencyRetry-safe synchronization
Vue 3Local-first interaction model
PiniaLocal-first interaction model
Offline-firstLocal-first interaction model
01 / Problem
A fragmented workflow slowed the whole system.
Retail checkout cannot depend entirely on continuous internet connectivity. Network latency or connection loss can interrupt sales, delay customers, and leave payment or inventory state incomplete when every action requires an immediate ERPNext request.
02 / Solution
One product model, expressed clearly at every layer.
I designed an offline-first POS client that persists checkout state and queued operations in IndexedDB. Local workflows remain usable without connectivity, and a controlled background process synchronizes pending operations with ERPNext after the connection returns.
Architecture replay
Walk through the system
Select a layer to inspect its responsibility.
Active layer 1
Quasar point-of-sale interface
Quasar point-of-sale interface owns the user-facing workflow and consumes a stable contract.
Responsibility stays explicit at this boundary.
Project media story
The system, seen in use
Artifacts are captioned with the engineering story they support.
Offline checkout
Checkout remains usable while the ERPNext connection is unavailable.
Pending synchronization
Locally persisted operations wait in a controlled queue until connectivity returns.
Recovery workflow
Queued operations synchronize with ERPNext after the connection is restored.
Decision log
Persist transactions before synchronization
- Context
- Checkout needed to remain usable during unstable connectivity
- Decision
- Stored transaction state in IndexedDB and synchronized through a background queue
- Trade-off
- Required conflict resolution and recovery logic but removed the network from the critical checkout path
Decision log
Assign stable operation identifiers
- Context
- Reconnection and request retries could submit the same operation more than once
- Decision
- Created stable identifiers for pending transaction operations
- Trade-off
- Added bookkeeping but supported safer retry behavior
03 / Challenges overcome
Complexity moved behind durable boundaries.
The primary challenge was reconciling local transactions with ERPNext inventory and accounting state without duplicate submissions. The solution required stable operation identifiers, controlled retries, connection-state handling, and clear recovery behavior for failed synchronization.
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