A medallion pipeline you can actually read

The problem

Medallion architecture gets described a lot more often than it gets shown. I wanted a complete, readable reference where each layer's responsibility is obvious and the whole thing is small enough to hold in your head.

What I did

• ▸Built the full pipeline: ingestion, layering, transformation and the analytics-ready output.
• ▸Defined the contract for each layer so responsibilities do not bleed across boundaries.
• ▸Kept it deliberately small; the point is legibility, not scale.

Architecture

• ▸Bronze is append-only and faithful to the source. No cleaning, no opinions: if you clean here, you can never reproduce what the source actually sent.
• ▸Silver deduplicates, enforces types and applies business rules. This is the layer that decides what 'correct' means.
• ▸Gold aggregates into the shapes a dashboard consumes, so query-time work stays trivial.
• ▸Each layer is a Delta table, which makes the boundaries inspectable and every step re-runnable.

What went wrong first

Results

layers with explicit contracts

3layers with explicit contracts

MIT-licensed and readable end to end

PublicMIT-licensed and readable end to end

A reference implementation is a teaching tool. The value is that someone can read all of it in one sitting and see exactly why each boundary exists.

Stack