Overlays

Mountaya publishes overlays grouped by purpose: terrain enrichment, weather, surface, and snow. Each is identified by a slug you use in the specification and tile URLs. Every overlay is reached with the same two endpoints, described below.

Overlay	Group	Description
`pois`	Terrain enrichment	Points of interest (huts, peaks, passes, parking, water) rendered as vector features.
`hillshade`	Terrain enrichment	Shaded-relief hillshade derived from the digital elevation model.
`temperature-actual`	Weather	Forecast air temperature.
`temperature-perceived`	Weather	Forecast perceived ("feels-like") temperature.
`temperature-soil`	Weather	Forecast soil-surface temperature.
`visibility`	Weather	Forecast horizontal visibility.
`humidity`	Weather	Forecast relative humidity.
`wind`	Weather	Forecast wind speed and direction.
`steepness`	Surface	Slope steepness classification from 25° to 45°+.
`aspectslope`	Surface	Combined slope aspect and steepness shading.
`snowdepth`	Snow	Modelled snow depth on the ground.
`snowfall-daily`	Snow	Forecast daily snowfall accumulation.
`snowfall-hourly`	Snow	Forecast hourly snowfall accumulation.

Weather and snow overlays accept a timestamp query parameter to select a forecast step; static overlays (pois, hillshade, aspectslope) ignore it.

Authentication

Every Tile API request carries a publishable key (pk_…) with the tiles scope in the X-API-Key header. If your organization enables session enforcement, also send a session token in X-Session-Token. Fetching a specification needs only the publishable key. See authentication for the full model and the query-parameter fallbacks for contexts that cannot set headers.

The specification endpoint

Before rendering an overlay, fetch its specification. It returns the MapLibre sources and layers to register, so you never hand-write source URLs or layer styling.

curl "https://tiles.mountaya.com/v1/overlays/{overlay}/specification" \
  -H "X-API-Key: pk_your_publishable_key"

Replace {overlay} with a slug from the catalog above. The response wraps a data object holding sources. Each source carries:

id

string

The source identifier to register on your map and to reference from each layer.

type

vector | raster

Whether the source serves vector or raster tiles. Raster sources also include a size (the tile pixel size).

tiles

string[]

The {z}/{x}/{y} tile URL templates for the source.

zoom_min

number

The lowest zoom level the source serves.

zoom_max

number

The highest zoom level the source serves.

attribution

string

The attribution string to display for the source's data.

layers

object[]

The layers to draw from the source. Each layer includes its id, type, zoom range, and the paint and layout to apply, so styling comes from the specification rather than your code.

See the quickstart for the loop that turns this response into MapLibre sources and layers, and the Tile API reference for the complete endpoint schema.

The tile URL template

The specification's tiles entries point at the tile endpoint, served on the standard slippy-map template:

https://tiles.mountaya.com/v1/overlays/{overlay}/{z}/{x}/{y}

{z}, {x}, and {y} are the tile zoom, column, and row. Your map renderer fills these in as it requests tiles; you rarely build this URL yourself, since the specification already supplies it. Tile requests carry the same X-API-Key header (and X-Session-Token when required).

The timestamp parameter

Weather and snow overlays are time-varying: they describe a forecast that changes hour to hour. Select a forecast step with an optional timestamp query parameter on the tile request.

curl "https://tiles.mountaya.com/v1/overlays/temperature-actual/9/268/183?timestamp=2026-06-03T14:00:00Z" \
  -H "X-API-Key: pk_your_publishable_key"

timestamp

string

An RFC 3339 instant (for example 2026-06-03T14:00:00Z). The value is normalized to UTC and rounded down to the hour. Accepted range is 3 days in the past to 6 days in the future. Omit it to default to the current hour.

The time-varying overlays are the weather and snow groups: temperature-actual, temperature-perceived, temperature-soil, visibility, humidity, wind, snowdepth, snowfall-daily, and snowfall-hourly. The terrain-enrichment and surface overlays (pois, hillshade, steepness, aspectslope) are static and ignore the parameter.

Refresh tiles when the time changes

Because the timestamp is part of the tile request, moving to a different forecast step is a new set of tiles. Update the source's tile URLs (or re-add the source) when your time selector changes so the map fetches the new step.

Next steps

Integration

Add overlays with MapLibre GL JS, Mapbox GL JS, the MapTiler SDK, or deck.gl.

API Reference

The full Tile API reference, generated from the OpenAPI specification.