Synchronization App Development for Salon Operations

Client name: Andreas Company: The Pretty Bar Athens Industry: Beauty & wellness / salon operations Objective: Design and deliver a safety-first proof of concept that synchronizes availability between Platform A and Platform B — so reception can reduce manual double-entry, monitor both calendars from one desktop app, and optionally enable guarded live writes when ready. Duration: Multi-phase PoC over several months (Milestones 2–4: sync engine → bidirectional logic → installable desktop app)

The Pretty Bar Athens runs bookings on two platforms that do not talk to each other natively. Reception staff were manually copying availability between Platform A and Platform B — slow, error-prone, and hard to scale.

The client needed more than a script on a developer laptop:

A tool reception could run on Windows without a terminal

Bidirectional sync (Platform A → Platform B and Platform B → Platform A)

No customer PII transferred — only availability blocks

Strong safety guardrails before any live calendar changes

Clear logs and monitoring so staff could trust what the system was doing

With a month of manual cross-platform entries already in the calendars, “turn everything on at once” was not an option. The product had to support monitor-only operation first, then controlled live rollout.

I delivered a phased PoC in three layers:

Reads both platforms via authenticated browser sessions (Playwright + Chrome)

Syncs availability only — start time, duration, staff — not names, phones, or notes

Bidirectional passes with independent safety rules per direction

Stable staff-ID mapping (Platform A staff_member_id ↔ Platform B employeeId)

SQLite ledger for idempotency, duplicate prevention, and loop prevention

Conflict detection — overlapping slots log CONFLICT and skip writes

Dry-run by default; live writes require explicit flags + allowlists

A dark-themed reception dashboard with:

Dashboard — last sync, platform counts, conflicts, staff mappings, trend charts, run breakdown

Sessions — guided Platform A/Platform B login; session health on one screen

Settings — sync direction, window, dry run, live writes, auto-sync interval

Activity log — structured table, raw JSON, ledger view, filters, CSV export

Windows + macOS installers via GitHub Releases (desktop-v0.1.0)

MkDocs documentation site with milestone handoff guides

Guarded live E2E evidence in both directions

22 automated tests covering mapping, ledger, orchestration, and writers

Repository transferred to the client with full history and releases

Sync engine TypeScript, Node.js, Playwright

Desktop app Electron, React, Framer Motion, MUI Charts

Data SQLite (sync ledger), structured JSON logs

Integrations Platform-A Pro API, Platform-B Partners (GraphQL + calendar reads)

Packaging & CI electron-builder, GitHub Actions

Documentation MkDocs Material, hosted docs site

Skills:

API integration

Desktop application development

System design

Technical documentation

CI/CD

Safety-critical workflow design

Client-approved delivery: Andreas tested the app on Windows against live calendars, approved milestones on Contra, and received full repo ownership with installer releases

Safe pilot mode: Reception runs dry run + auto-sync — continuous monitoring with zero calendar writes until allowlists are deliberately configured

Operational visibility: Each sync completes in ~15 seconds with a clear breakdown (creates, skips, conflicts, errors) and exportable CSV logs

Scale handled: Engine processes hundreds of calendar entries per run across 7 mapped staff on both platforms

Conflicts surfaced, not hidden: Overlaps (e.g. from manual duplicate entries) log as CONFLICT for review instead of blind writes

Clear handoff: Client confirmed setup notes were “clear and helpful” for monitor-only rollout; MVP phase planned when investor timing allows