Helios is a web app that calculates the optimal seat side — left or right — for any ground journey. Enter your origin, destination, departure time, and sun/shade preference, and Helios works out exactly where to sit at every stage of the trip using solar-position mathematics and great-circle routing.Documentation Index
Fetch the complete documentation index at: https://mintlify.com/V3RNE42/helios/llms.txt
Use this file to discover all available pages before exploring further.
Introduction
Learn what Helios does and how it models your journey
Quickstart
Run Helios locally in under five minutes
Core Algorithm
Understand the sun/shade logic that drives every result
API Reference
Explore the serverless geocoding and timezone endpoints
What Helios solves
When you travel in a vehicle, the sun moves relative to your direction of travel. Depending on whether it is before or after solar noon, and whether you are heading north or south, the sun falls on one side of the vehicle. Helios maps this mathematically so you can plan your seat in advance.Set your preferences
Choose whether you want sun or shade, and whether you can change seats mid-trip.
Key features
Solar-accurate calculations
Uses two independent solar libraries to compute solar noon, sunrise, and sunset at every point along the route.
Multi-day route support
Handles journeys spanning multiple days by iterating through each day’s solar events along the great-circle path.
Time zone awareness
Optionally adjusts all displayed times to the local clock at each point — useful for long cross-zone trips.
Privacy-first API design
The browser never calls third-party APIs directly. All geocoding and timezone lookups go through same-origin Vercel serverless functions that hold keys server-side.