Exceed 23 waypoint per request limit on Google Directions API (Business/Work level)

function initMap() {
    var service = new google.maps.DirectionsService;
    var map = new google.maps.Map(document.getElementById('map'));

    // list of points
    var stations = [
        {lat: 48.9812840, lng: 21.2171920, name: 'Station 1'},
        {lat: 48.9832841, lng: 21.2176398, name: 'Station 2'},
        {lat: 48.9856443, lng: 21.2209088, name: 'Station 3'},
        {lat: 48.9861461, lng: 21.2261563, name: 'Station 4'},
        {lat: 48.9874682, lng: 21.2294855, name: 'Station 5'},
        {lat: 48.9909244, lng: 21.2295512, name: 'Station 6'},
        {lat: 48.9928871, lng: 21.2292352, name: 'Station 7'},
        {lat: 48.9921334, lng: 21.2246742, name: 'Station 8'},
        {lat: 48.9943196, lng: 21.2234792, name: 'Station 9'},
        {lat: 48.9966345, lng: 21.2221262, name: 'Station 10'},
        {lat: 48.9981191, lng: 21.2271386, name: 'Station 11'},
        {lat: 49.0009168, lng: 21.2359527, name: 'Station 12'},
        {lat: 49.0017950, lng: 21.2392890, name: 'Station 13'},
        {lat: 48.9991912, lng: 21.2398272, name: 'Station 14'},
        {lat: 48.9959850, lng: 21.2418410, name: 'Station 15'},
        {lat: 48.9931772, lng: 21.2453901, name: 'Station 16'},
        {lat: 48.9963512, lng: 21.2525850, name: 'Station 17'},
        {lat: 48.9985134, lng: 21.2508423, name: 'Station 18'},
        {lat: 49.0085000, lng: 21.2508000, name: 'Station 19'},
        {lat: 49.0093000, lng: 21.2528000, name: 'Station 20'},
        {lat: 49.0103000, lng: 21.2560000, name: 'Station 21'},
        {lat: 49.0112000, lng: 21.2590000, name: 'Station 22'},
        {lat: 49.0124000, lng: 21.2620000, name: 'Station 23'},
        {lat: 49.0135000, lng: 21.2650000, name: 'Station 24'},
        {lat: 49.0149000, lng: 21.2680000, name: 'Station 25'},
        {lat: 49.0171000, lng: 21.2710000, name: 'Station 26'},
        {lat: 49.0198000, lng: 21.2740000, name: 'Station 27'},
        {lat: 49.0305000, lng: 21.3000000, name: 'Station 28'},
    ];
    
    // Zoom and center map automatically by stations (each station will be in visible map area)
    var lngs = stations.map(function(station) { return station.lng; });
    var lats = stations.map(function(station) { return station.lat; });
    map.fitBounds({
        west: Math.min.apply(null, lngs),
        east: Math.max.apply(null, lngs),
        north: Math.min.apply(null, lats),
        south: Math.max.apply(null, lats),
    });
    
    // Show stations on the map as markers
    for (var i = 0; i < stations.length; i++) {
        if (!stations[i].name)
            continue;
        new google.maps.Marker({
            position: stations[i],
            map: map,
            title: stations[i].name
        });
    }

    // Divide route to several parts because max stations limit is 25 (23 waypoints + 1 origin + 1 destination)
    for (var i = 0, parts = [], max = 8 - 1; i < stations.length; i = i + max)
        parts.push(stations.slice(i, i + max + 1));

    // Callback function to process service results
    var service_callback = function(response, status) {
        if (status != 'OK') {
            console.log('Directions request failed due to ' + status);
            return;
        }
        var renderer = new google.maps.DirectionsRenderer;
        renderer.setMap(map);
        renderer.setOptions({ suppressMarkers: true, preserveViewport: true });
        renderer.setDirections(response);
    };
        
    // Send requests to service to get route (for stations count <= 25 only one request will be sent)
    for (var i = 0; i < parts.length; i++) {
        // Waypoints does not include first station (origin) and last station (destination)
        var waypoints = [];
        for (var j = 1; j < parts[i].length - 1; j++)
            waypoints.push({location: parts[i][j], stopover: false});
        // Service options
        var service_options = {
            origin: parts[i][0],
            destination: parts[i][parts[i].length - 1],
            waypoints: waypoints,
            travelMode: 'WALKING'
        };
        // Send request
        service.route(service_options, service_callback);
    }
  }

html, body {
    height: 100%;
    margin: 0;
    padding: 0;
}
#map {
    height: 100%;     
    width: 100%;
    height: 100%;
}

<div id="map"></div>

<!-- without API KEY set variable "max" to 8 -->
<script async defer src="https://maps.googleapis.com/maps/api/js?callback=initMap"></script>

<!-- with API KEY set variable "max" to 25 -->
<!-- <script async defer src="https://maps.googleapis.com/maps/api/js?callback=initMap&key=YOUR_API_KEY"></script>-->

With following code you can use as many waypoints as you need and you will never get error MAX_WAYPOINTS_EXCEEDED. Do not forget to replace "YOUR_API_KEY" to your API KEY or remove &key=YOUR_API_KEY from google API URL and set variable "max" to 8 (max = 25 when using API KEY, max = 8 when not using API KEY).

<style>
html, body { height: 100%; margin: 0; padding: 0; }
#map { height: 100%; width: 100%; height: 100%; }
</style>
<div id="map"></div>
<script>
  function initMap() {
    var service = new google.maps.DirectionsService;
    var map = new google.maps.Map(document.getElementById('map'));

    // list of points
    var stations = [
        {lat: 48.9812840, lng: 21.2171920, name: 'Station 1'},
        {lat: 48.9832841, lng: 21.2176398, name: 'Station 2'},
        {lat: 48.9856443, lng: 21.2209088, name: 'Station 3'},
        {lat: 48.9861461, lng: 21.2261563, name: 'Station 4'},
        {lat: 48.9874682, lng: 21.2294855, name: 'Station 5'},
        {lat: 48.9909244, lng: 21.2295512, name: 'Station 6'},
        {lat: 48.9928871, lng: 21.2292352, name: 'Station 7'},
        {lat: 48.9921334, lng: 21.2246742, name: 'Station 8'},
        {lat: 48.9943196, lng: 21.2234792, name: 'Station 9'},
        {lat: 48.9966345, lng: 21.2221262, name: 'Station 10'},
        {lat: 48.9981191, lng: 21.2271386, name: 'Station 11'},
        {lat: 49.0009168, lng: 21.2359527, name: 'Station 12'},
        {lat: 49.0017950, lng: 21.2392890, name: 'Station 13'},
        {lat: 48.9991912, lng: 21.2398272, name: 'Station 14'},
        {lat: 48.9959850, lng: 21.2418410, name: 'Station 15'},
        {lat: 48.9931772, lng: 21.2453901, name: 'Station 16'},
        {lat: 48.9963512, lng: 21.2525850, name: 'Station 17'},
        {lat: 48.9985134, lng: 21.2508423, name: 'Station 18'},
        {lat: 49.0085000, lng: 21.2508000, name: 'Station 19'},
        {lat: 49.0093000, lng: 21.2528000, name: 'Station 20'},
        {lat: 49.0103000, lng: 21.2560000, name: 'Station 21'},
        {lat: 49.0112000, lng: 21.2590000, name: 'Station 22'},
        {lat: 49.0124000, lng: 21.2620000, name: 'Station 23'},
        {lat: 49.0135000, lng: 21.2650000, name: 'Station 24'},
        {lat: 49.0149000, lng: 21.2680000, name: 'Station 25'},
        {lat: 49.0171000, lng: 21.2710000, name: 'Station 26'},
        {lat: 49.0198000, lng: 21.2740000, name: 'Station 27'},
        {lat: 49.0305000, lng: 21.3000000, name: 'Station 28'},
        // ... as many other stations as you need
    ];

    // Zoom and center map automatically by stations (each station will be in visible map area)
    var lngs = stations.map(function(station) { return station.lng; });
    var lats = stations.map(function(station) { return station.lat; });
    map.fitBounds({
        west: Math.min.apply(null, lngs),
        east: Math.max.apply(null, lngs),
        north: Math.min.apply(null, lats),
        south: Math.max.apply(null, lats),
    });

    // Show stations on the map as markers
    for (var i = 0; i < stations.length; i++) {
        new google.maps.Marker({
            position: stations[i],
            map: map,
            title: stations[i].name
        });
    }

    // Divide route to several parts because max stations limit is 25 (23 waypoints + 1 origin + 1 destination)
    for (var i = 0, parts = [], max = 25 - 1; i < stations.length; i = i + max)
        parts.push(stations.slice(i, i + max + 1));

    // Service callback to process service results
    var service_callback = function(response, status) {
        if (status != 'OK') {
            console.log('Directions request failed due to ' + status);
            return;
        }
        var renderer = new google.maps.DirectionsRenderer;
        renderer.setMap(map);
        renderer.setOptions({ suppressMarkers: true, preserveViewport: true });
        renderer.setDirections(response);
    };

    // Send requests to service to get route (for stations count <= 25 only one request will be sent)
    for (var i = 0; i < parts.length; i++) {
        // Waypoints does not include first station (origin) and last station (destination)
        var waypoints = [];
        for (var j = 1; j < parts[i].length - 1; j++)
            waypoints.push({location: parts[i][j], stopover: false});
        // Service options
        var service_options = {
            origin: parts[i][0],
            destination: parts[i][parts[i].length - 1],
            waypoints: waypoints,
            travelMode: 'WALKING'
        };
        // Send request
        service.route(service_options, service_callback);
    }
  }
</script>
<script async defer src="https://maps.googleapis.com/maps/api/js?key=YOUR_API_KEY&callback=initMap"></script>

fiddle with show/hide line buttons

You are correct the premier pricing is rather expensive starting at $10,000, last time I spoke with a google rep on the phone.

I found a workaround that I put into place to in a way bypasss the 8 waypoints limitation. I was able to make it work.

I did this by receiving my waypoints and breaking them up into different routes but drawing them together as the same route.

Example being if there were 30 waypoints needed I would draw 4 lines, but with the same color etc. So, basically you cut the waypoints into different routes calling the directions renderer each time as if it was a different route. The key is after the first route that the next route has to start with the last waypoint of the previous route (this makes sure that the route lines are connected to each other)

It works but you need to write a lot more code than what you would if you had a premier account, and you are calling for directions a lot more in this instance.

I have searched and thought about other ways to do this without having a premier account and have failed.

Although, I when speaking with google they did say that they intended on creating a tiered structure of payment for customers with different wants/needs. For instance, if a customer just needed more waypts and not a bunch more direction requests.

Hope this helps, as it worked for me in a practice application.