diff --git a/docs/release-notes.md b/docs/release-notes.md
index 7a052af99..828ef200e 100644
--- a/docs/release-notes.md
+++ b/docs/release-notes.md
@@ -47,6 +47,9 @@
     * `CustomLocations` entries which use the new [unique string ID](https://stardewvalleywiki.com/Modding:Common_data_field_types#Unique_string_ID) format;
     * `AddWarps` warps when a location name contains a dot.
 
+* For the web API:
+  * The [anonymized metrics for update check requests](technical/web.md#modsmetrics) now counts requests by SMAPI and game version.
+
 ## 4.0.8
 Released 21 April 2024 for Stardew Valley 1.6.4 or later.
 
@@ -165,6 +168,7 @@ Released 19 March 2024 for Stardew Valley 1.6.0 or later. See [release highlight
 
 * For the web UI:
   * Updated JSON validator for Content Patcher 2.0.0.
+  * Added [anonymized metrics for update check requests](technical/web.md#modsmetrics).
   * Fixed uploaded log/JSON file expiry alway shown as renewed.
   * Fixed update check for mods with a prerelease version tag not recognized by the ModDrop API. SMAPI now parses the version itself if needed.
 
diff --git a/docs/technical/web.md b/docs/technical/web.md
index fefe15353..4b99436b7 100644
--- a/docs/technical/web.md
+++ b/docs/technical/web.md
@@ -189,7 +189,7 @@ may be useful to external tools.
 
 Example request:
 ```js
-POST https://smapi.io/api/v3.0/mods
+POST https://smapi.io/api/v4.0.0/mods
 {
    "mods": [
       {
@@ -199,8 +199,8 @@ POST https://smapi.io/api/v3.0/mods
          "isBroken": false
       }
    ],
-   "apiVersion": "3.0.0",
-   "gameVersion": "1.4.0",
+   "apiVersion": "4.0.0",
+   "gameVersion": "1.6.9",
    "platform": "Windows",
    "includeExtendedMetadata": true
 }
@@ -329,7 +329,7 @@ deployed or restarted.
 
 Example request:
 ```js
-GET https://smapi.io/api/v3.0/mods/metrics
+GET https://smapi.io/api/v4.0.0/mods/metrics
 ```
 
 ## Short URLs
diff --git a/src/SMAPI.Web/Controllers/ModsApiController.cs b/src/SMAPI.Web/Controllers/ModsApiController.cs
index 64c95dacf..844c7efba 100644
--- a/src/SMAPI.Web/Controllers/ModsApiController.cs
+++ b/src/SMAPI.Web/Controllers/ModsApiController.cs
@@ -83,7 +83,7 @@ public ModsApiController(IWebHostEnvironment environment, IWikiCacheRepository w
         public async Task<IEnumerable<ModEntryModel>> PostAsync([FromBody] ModSearchModel? model, [FromRoute] string version)
         {
             ApiMetricsModel metrics = MetricsManager.GetMetricsForNow();
-            metrics.TrackRequest();
+            metrics.TrackRequest(model?.ApiVersion, model?.GameVersion);
 
             if (model?.Mods == null)
                 return Array.Empty<ModEntryModel>();
diff --git a/src/SMAPI.Web/Framework/Metrics/ApiMetricsModel.cs b/src/SMAPI.Web/Framework/Metrics/ApiMetricsModel.cs
index e3d68c806..310b9d335 100644
--- a/src/SMAPI.Web/Framework/Metrics/ApiMetricsModel.cs
+++ b/src/SMAPI.Web/Framework/Metrics/ApiMetricsModel.cs
@@ -1,3 +1,4 @@
+using System;
 using System.Collections.Generic;
 using StardewModdingAPI.Toolkit.Framework.UpdateData;
 
@@ -15,14 +16,28 @@ internal class ApiMetricsModel
         /// <summary>The metrics by mod site.</summary>
         public Dictionary<ModSiteKey, MetricsModel> Sites { get; } = new();
 
+        /// <summary>The number of update-check requests by SMAPI version.</summary>
+        public Dictionary<string, long> ByApiVersion { get; } = new(StringComparer.OrdinalIgnoreCase);
+
+        /// <summary>The number of update-check requests by game version.</summary>
+        public Dictionary<string, long> ByGameVersion { get; } = new(StringComparer.OrdinalIgnoreCase);
+
 
         /*********
         ** Public methods
         *********/
         /// <summary>Track an update-check request received by the API.</summary>
-        public void TrackRequest()
+        /// <param name="apiVersion">The SMAPI version installed by the player.</param>
+        /// <param name="gameVersion">The game version installed by the player.</param>
+        public void TrackRequest(ISemanticVersion? apiVersion, ISemanticVersion? gameVersion)
         {
             this.ApiRequests++;
+
+            string apiVersionStr = apiVersion?.ToString() ?? "<none specified>";
+            string gameVersionStr = gameVersion?.ToString() ?? "<none specified>";
+
+            this.ByApiVersion[apiVersionStr] = this.ByApiVersion.GetValueOrDefault(apiVersionStr) + 1;
+            this.ByGameVersion[gameVersionStr] = this.ByGameVersion.GetValueOrDefault(gameVersionStr) + 1;
         }
 
         /// <summary>Track the update-check result for a specific update key.</summary>
diff --git a/src/SMAPI.Web/Framework/Metrics/MetricsManager.cs b/src/SMAPI.Web/Framework/Metrics/MetricsManager.cs
index 0189e12e1..1dc32391f 100644
--- a/src/SMAPI.Web/Framework/Metrics/MetricsManager.cs
+++ b/src/SMAPI.Web/Framework/Metrics/MetricsManager.cs
@@ -47,6 +47,8 @@ public static MetricsSummary GetSummary(ModUpdateCheckConfig config)
             var totals = new MetricsModel();
             var bySite = new Dictionary<ModSiteKey, MetricsModel>();
             var byDate = new Dictionary<string, ApiMetricsModel>();
+            var byApiVersion = new Dictionary<string, long>(StringComparer.OrdinalIgnoreCase);
+            var byGameVersion = new Dictionary<string, long>(StringComparer.OrdinalIgnoreCase);
             foreach ((string hourlyKey, ApiMetricsModel hourly) in MetricsManager.Metrics)
             {
                 // totals
@@ -68,6 +70,12 @@ public static MetricsSummary GetSummary(ModUpdateCheckConfig config)
                 if (!byDate.TryGetValue(dailyKey, out ApiMetricsModel? daily))
                     byDate[dailyKey] = daily = new ApiMetricsModel();
 
+                // by version
+                foreach ((string apiVersion, long count) in hourly.ByApiVersion)
+                    byApiVersion[apiVersion] = byApiVersion.GetValueOrDefault(apiVersion) + count;
+                foreach ((string gameVersion, long count) in hourly.ByGameVersion)
+                    byGameVersion[gameVersion] = byGameVersion.GetValueOrDefault(gameVersion) + count;
+
                 daily.AggregateFrom(hourly);
             }
 
@@ -80,6 +88,8 @@ public static MetricsSummary GetSummary(ModUpdateCheckConfig config)
                 TotalCacheHits: totals.CacheHits,
                 TotalSuccessCacheMisses: totals.SuccessCacheMisses,
                 TotalErrorCacheMisses: totals.ErrorCacheMisses,
+                ByApiVersion: byApiVersion,
+                ByGameVersion: byGameVersion,
                 BySite: bySite,
                 ByDate: byDate
             );
diff --git a/src/SMAPI.Web/Framework/Metrics/MetricsSummary.cs b/src/SMAPI.Web/Framework/Metrics/MetricsSummary.cs
index 847b88049..954bb3067 100644
--- a/src/SMAPI.Web/Framework/Metrics/MetricsSummary.cs
+++ b/src/SMAPI.Web/Framework/Metrics/MetricsSummary.cs
@@ -13,6 +13,8 @@ namespace StardewModdingAPI.Web.Framework.Metrics
     /// <param name="TotalCacheHits">The number of times an update key returned data from the cache.</param>
     /// <param name="TotalSuccessCacheMisses">The number of times an update key successfully fetched data from a remote mod site.</param>
     /// <param name="TotalErrorCacheMisses">The number of times an update key could not fetch data from a remote mod site (e.g. mod page didn't exist or mod site returned an API error).</param>
+    /// <param name="ByApiVersion">The number of update-check request by SMAPI version.</param>
+    /// <param name="ByGameVersion">The number of update-check request by game version.</param>
     /// <param name="BySite">The metrics grouped by site.</param>
     /// <param name="ByDate">The metrics grouped by UTC date.</param>
     internal record MetricsSummary(
@@ -24,6 +26,8 @@ internal record MetricsSummary(
         int TotalCacheHits,
         int TotalSuccessCacheMisses,
         int TotalErrorCacheMisses,
+        IDictionary<string, long> ByApiVersion,
+        IDictionary<string, long> ByGameVersion,
         IDictionary<ModSiteKey, MetricsModel> BySite,
         IDictionary<string, ApiMetricsModel> ByDate
     );