Database-enforced commands
Browser clients cannot write queue tables directly. Every mutation crosses an explicit PostgreSQL function that authorizes the actor and applies one atomic state change.
Real-time product · Queue management
Next
Production v1.0 / 2026One synchronized answer to three questions: who is waiting, who is being served, and who is next.
The product
A small workflow with three distinct audiences.
Paper lists and shouted names create uncertainty for customers and unnecessary coordination for staff.
Next gives customers a stable queue number and position, staff a focused command board, and public displays a privacy-safe view of the active number. All three experiences share persistent state and converge without manual refresh.
- 01Create a queue and receive a one-time staff capability
- 02Let customers join without permanent accounts
- 03Call, complete, skip, pause, reopen, or close from staff view
- 04Keep customer and public displays synchronized safely
Product experience
Purpose-built views, one authoritative queue.
Architecture
Authorization and consistency live with the data.
Next.js serves the interface from Vercel. Supabase provides anonymous authentication, PostgreSQL, RPC access, and filtered Realtime signals. The browser receives public configuration only; privileged credentials never enter the application runtime.
Realtime as invalidation
Realtime messages tell clients that something changed; each client then fetches a revisioned authoritative snapshot and ignores stale responses.
Idempotent transitions
Every command receives a request UUID. Safe replays return the current result while mismatched reuse is rejected before state can diverge.
Privacy by separation
Public displays expose queue numbers only. Optional customer names live in a private table and are available only to authorized staff.
Release evidence
Quality measured across the complete system.
The release was validated at the interface, domain, database, integration, browser, and production layers without counting the focused Realtime subset twice.
- 34
- unit and component checks
- 62
- database authorization checks
- 11
- Supabase integration checks
- 15
- browser workflow checks
- 9
- production smoke checks
The project documentation also records free-tier limits, anonymous identity tradeoffs, recovery constraints, and deployment boundaries instead of presenting a portfolio release as an enterprise service.
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