Scope your booking system around the availability model

The availability model does most of the work: the inventory of what can be reserved (seats, slots, facilities, appointments), the rules that govern it (lead times, cancellation windows, overlapping holds), and the concurrency handling that stops double-booking under load. The document scopes those alongside the visible parts — search, checkout, confirmations — because the visible parts are rarely where booking builds run into trouble.

Usually when the booking rules are the business: complex availability logic, multi-resource reservations, dynamic pricing, or deep integration with your own operations that configurable scheduling tools cannot express. If your description fits a standard appointment grid, the document will not pretend otherwise — a custom scope is only worth building when the rules outgrow what you can configure.

An executive summary, the proposed architecture direction, functional scope, top delivery risks, and a milestone sketch — the same structure our paid scoping work follows, generated from your description and formatted as a shareable PDF.

The pipeline drafts against real DBB Software delivery content — case studies, service pages, published engineering material — and a verification pass flags anything it cannot trace. T-shirt effort tiers come from our delivery history; dollar figures only ever come from our published rate band, never from the model.

Yes. The preview needs no email at all; the full PDF costs one email address. We make the document genuinely useful because some readers will want the fixed-bid version afterwards — that is the whole business model, no tricks.

The free Scope Document is the full, AI-generated scope of your project — architecture, risks, milestones, and the open questions to firm up — drafted in minutes and emailed to you. The $1,777 Discovery Sprint is for when you need a number you can sign: 2-3 weeks with a senior architect, a deeper human-authored SDD, and a fixed bid within ±15%.

The same ones professional engineering teams use, not a generic template: arc42 for the architecture structure, IEEE 1016 for the design specification, the C4 model for diagrams, and ISO/IEC/IEEE 29148 for requirements. Requirements are prioritised with MoSCoW, decisions are captured as Architecture Decision Records (ADRs), and the paid Sprint deliverable adds a PMI-style Work Breakdown Structure plus agile delivery artefacts (Sprint 0, RACI, Definition of Done).

A current, mainstream, production-proven stack chosen for your specific build — for a typical data-heavy web/SaaS product that means Next.js 16 / React 19 on the front end, a Node.js (NestJS) or Python (FastAPI) back end, PostgreSQL 17, Redis, and cloud infrastructure on AWS/GCP/Azure or Vercel, with Auth0 for identity. Every choice is documented as an ADR with the alternatives we weighed and why, so nothing is a black box. We track current stable releases, so recommendations stay up to date.

Yes — rendered diagrams, not hand-waving: a system-architecture (C4-style) view, a data-flow diagram, key sequence diagrams, an entity-relationship (ERD) data model, and — in the Sprint deliverable — a deployment topology and a delivery roadmap. They are generated from your scope and laid out as proper figures.

A short, standardised record of one significant technical decision — its context, the options considered, the choice, and the consequences (the pattern popularised by Michael Nygard). They make the reasoning auditable and let a new engineer understand why the system is built the way it is. Each scope document includes the ADRs that matter for your build.

The free document sizes the work in calibrated t-shirt effort tiers and flags the cost drivers. The paid Discovery Sprint goes further: a Work Breakdown Structure with an effort band per workstream, a basis-of-estimate (drivers, assumptions, contingency), and a fixed bid within ±15% — the artefacts a finance owner needs to set a number, not a vibe.

That is the point of the Discovery Sprint deliverable: alongside the architecture and requirements it includes a sprint-by-sprint delivery plan, a Sprint 0 / mobilization checklist (environments, CI/CD, access), a RACI matrix, a Definition of Done, and a change-control process — everything needed to kick off cleanly. The free document gives the architecture and scope direction to brief a team.

Compliance is treated as a first-class concern: a data-handling table (data class, lawful basis, retention, residency), security and privacy non-functional requirements, and — where relevant — readiness against regimes like UK/EU GDPR, HIPAA, NHS DSP Toolkit, and SOC 2. For regulated builds the architecture is designed to the strictest detected regime by default.