Seeking alternative to Google Maps Elevation API

I've been working on opentopodata.org as a free, open alternative to the Google Maps Elevation API.

Request URLs look like this:

https://api.opentopodata.org/v1/eudem25m?locations=51.875127,-3.341298

and the response is similar to Google Maps:

{
  "results": [
    {
      "elevation": 502.43035888671875, 
      "location": {
        "lat": 51.875127, 
        "lng": -3.341298
      }
    }
  ], 
  "status": "OK"
}

Open Topo Data is MIT licensed. You can host it yourself or use the free public API.

The public API has a number of open DEM datasets loaded, including a 30m global dataset, the 25m EU-DEM dataset for Europe, and the 10m NED dataset for the US.

You could try https://elevation-api.io

This is an API which returns elevation data, just as Google does, maybe you'll find it as a suitable replacement.

Disclaimer: I am the developer of the site, but also needed an alternative.

For those continuing to search (I was and landed here). There is a free USGS service which is well buried. Link here. Worked for my use case of a couple of dozen points. HT to @barrycarter for the index link.