Geo2Tz

Geo2Tz is a minimal, self-hostable HTTP service that returns the IANA time zone identifier for a pair of geographic coordinates (latitude, longitude). It exposes a simple REST-like endpoint and uses prebuilt timezone polygon data to map coordinates to time zones.

Key Features

• Single REST endpoint GET /tz/{lat}/{lon} that returns JSON with coordinates and the matched IANA timezone
• Uses timezone polygon data produced from the timezone-boundary-builder project for accurate boundaries
• Distributed as a single Go binary and official container image, with Docker Compose and Kubernetes examples
• CLI command to update or pin the timezone dataset (update current/latest/specific-version)
• Optional token-based request authorization via environment variables
• Small, production-focused codebase written in Go, suitable for embedding in infrastructure or edge services

Use Cases

• Provide privacy-preserving timezone lookup for mobile or web apps without sending coordinates to third parties
• Add timezone resolution to logging, scheduling, or event-processing pipelines based on geolocated data
• Deploy as an internal microservice for geospatial backends and API gateways

Limitations and Considerations

• Requires downloading and maintaining the timezone polygon dataset; initial dataset can be sizable and needs storage
• Designed for single-coordinate lookups; no built-in batch lookup API or web UI
• Accuracy depends on the underlying timezone-boundary-builder dataset; edge cases near boundaries may require dataset updates

Geo2Tz is focused on a single, well-scoped problem and is suitable when you need a lightweight, self-hosted timezone resolution service. It is intended for deployments where privacy and control over coordinate data are important.