Capstan Cloud

Capstan Cloud is a multi-tenant SaaS platform that replaces paper forms and spreadsheets in manufacturing environments with dynamic digital data entry, automated reporting, and threshold-based alerts. Each manufacturing organization gets a fully isolated tenant with its own subdomain, configurable forms, and reporting workflows — no code changes required.

Technical Approach

The core innovation is a dynamic forms engine backed by PostgreSQL JSONB. Admins define form schemas through the UI — selecting from 14 field types including computed fields with formula evaluation, conditional visibility rules, and lookup references to tenant-specific machines, products, and customers. Submissions store data as field-value pairs in JSONB, enabling flexible querying and aggregation without schema migrations.

The reporting system uses a plugin registry architecture with composable section types — cover pages, data tables, summary statistics, trend charts, bar charts, pie charts, box-whisker plots, and barcodes. Reports are generated on the fly from live data using ReportLab, with tenant branding applied automatically. Celery workers handle async report generation, alert evaluation, and scheduled email delivery with priority queuing.

A Tauri desktop application provides offline capability for shops with unreliable connectivity. It maintains a local SQLite database that syncs with the cloud when back online, ensuring production data entry is never blocked by network issues.

Key Decisions

FastAPI backend for async performance on data-heavy operations. JSONB over entity-attribute-value tables for simpler querying with PostgreSQL indexing support. Application-level tenant isolation with a TenantMixin pattern rather than row-level security or schema-per-tenant — trading database-enforced isolation for operational simplicity at the current scale. Tauri over Electron for the desktop client to minimize resource usage on shop floor machines.