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John Charlie CatedrillaSelected work

Work note

Public Data Systems

Systems where data is the product: modeling, cleaning, and serving datasets so downstream users — developers, analysts, or the public — can actually use them.

This is a representative work note, not a public product case study. It describes the class of problem, the scope of the work, and the engineering practices involved; client identities, product specifics, figures, and implementation details are deliberately withheld to respect confidentiality.

The problem

Publishing data for broad use is different from storing it: the audience is untrusted and first-time, traffic is spiky, and every ambiguity in the schema becomes a support burden downstream.

Scope of the work

  • Model datasets and their access paths: schemas, field definitions, filtering, and pagination.
  • Implement APIs and search interfaces that answer a consumer's actual questions without requiring bulk downloads.
  • Build ingestion and cleaning steps so downstream consumers receive validated data rather than cleanup work.
  • Write usage documentation and examples alongside the data itself.

Engineering considerations

  • Publish the data's shape, not just the data — schemas, field definitions, and update frequency prevent most downstream confusion.
  • Serve stale-but-labeled data over failing, and make freshness explicit instead of silent.
  • Cache deliberately; broad-audience traffic is unauthenticated and arrives in bursts.
  • Validate at ingestion so errors surface where they are cheapest to fix.
  • Design queries for the consumer's question — good filtering and pagination beat full exports.

Capabilities demonstrated

  • Data modeling and schema design
  • API design
  • Search and filtering interfaces
  • Data cleaning and validation pipelines
  • Technical documentation

Technology categories

  • Python data tooling
  • Node.js APIs
  • PostgreSQL
  • React frontends