Data Sources and Methodology
Full transparency on dataset provenance, normalization rules, and quality checks used to publish postal code data at global scale.
Current Repository Facts
These figures are computed from the current production dataset snapshot (version 2026.3), last verified on 2026-03-19.
Source Aggregation Model
Postalcodes.info is a multi-source aggregator. Inputs are consolidated from official publications, open government data, and established public gazetteers where available.
Primary Geospatial Backbone
The repository uses normalized WGS84 coordinates and administrative hierarchies aligned to ISO-style country coding. This creates a stable schema across countries with very different native source formats.
Country-Specific Inputs
For countries with published postal references, upstream updates are merged into the canonical schema and validated before release. For each record, coordinates are treated as approximate administrative centroids, not parcel-level survey points.
Normalization and Validation Pipeline
Schema standardization
Local source formats are normalized into a single repository schema (country code, postal code, place name, admin levels, latitude, longitude). This reduces downstream ETL friction for users consuming multi-country data.
Current quality check results
- Geocoded row coverage: 100.00% of published rows include latitude and longitude.
- Out-of-range coordinates: 0 rows currently fall outside valid WGS84 bounds.
- Admin level coverage: L1 present in 78.74% of rows; L2 present in 72.21% of rows.
Known limitations and practical usage notes
- Coordinates represent approximate locality centroids and are not suitable for rooftop geocoding.
- Postal semantics vary by country (format, granularity, and retirement cadence), so local verification is recommended for critical workflows.
- Operational change logs and rebuild notes are published in /updates.
- For licensing context and attribution obligations, see /licensing.