diff --git a/service/src/main/java/org/whispersystems/textsecuregcm/controllers/ChallengeController.java b/service/src/main/java/org/whispersystems/textsecuregcm/controllers/ChallengeController.java
index e0dedfdcd..7a7907ce0 100644
--- a/service/src/main/java/org/whispersystems/textsecuregcm/controllers/ChallengeController.java
+++ b/service/src/main/java/org/whispersystems/textsecuregcm/controllers/ChallengeController.java
@@ -15,21 +15,31 @@ import javax.ws.rs.POST;
 import javax.ws.rs.PUT;
 import javax.ws.rs.Path;
 import javax.ws.rs.Produces;
+import javax.ws.rs.core.HttpHeaders;
 import javax.ws.rs.core.MediaType;
 import javax.ws.rs.core.Response;
+import io.micrometer.core.instrument.Metrics;
+import io.micrometer.core.instrument.Tag;
+import io.micrometer.core.instrument.Tags;
 import org.whispersystems.textsecuregcm.auth.AuthenticatedAccount;
 import org.whispersystems.textsecuregcm.entities.AnswerChallengeRequest;
 import org.whispersystems.textsecuregcm.entities.AnswerPushChallengeRequest;
 import org.whispersystems.textsecuregcm.entities.AnswerRecaptchaChallengeRequest;
 import org.whispersystems.textsecuregcm.limits.RateLimitChallengeManager;
+import org.whispersystems.textsecuregcm.metrics.UserAgentTagUtil;
 import org.whispersystems.textsecuregcm.push.NotPushRegisteredException;
 import org.whispersystems.textsecuregcm.util.ForwardedIpUtil;
 
+import static org.whispersystems.textsecuregcm.metrics.MetricsUtil.name;
+
 @Path("/v1/challenge")
 public class ChallengeController {
 
   private final RateLimitChallengeManager rateLimitChallengeManager;
 
+  private static final String CHALLENGE_RESPONSE_COUNTER_NAME = name(ChallengeController.class, "challengeResponse");
+  private static final String CHALLENGE_TYPE_TAG = "type";
+
   public ChallengeController(final RateLimitChallengeManager rateLimitChallengeManager) {
     this.rateLimitChallengeManager = rateLimitChallengeManager;
   }
@@ -40,16 +50,20 @@ public class ChallengeController {
   @Consumes(MediaType.APPLICATION_JSON)
   public Response handleChallengeResponse(@Auth final AuthenticatedAccount auth,
       @Valid final AnswerChallengeRequest answerRequest,
-      @HeaderParam("X-Forwarded-For") String forwardedFor) throws RetryLaterException {
+      @HeaderParam("X-Forwarded-For") final String forwardedFor,
+      @HeaderParam(HttpHeaders.USER_AGENT) final String userAgent) throws RetryLaterException {
+
+    Tags tags = Tags.of(UserAgentTagUtil.getPlatformTag(userAgent));
 
     try {
-      if (answerRequest instanceof AnswerPushChallengeRequest) {
-        final AnswerPushChallengeRequest pushChallengeRequest = (AnswerPushChallengeRequest) answerRequest;
+      if (answerRequest instanceof final AnswerPushChallengeRequest pushChallengeRequest) {
+        tags = tags.and(CHALLENGE_TYPE_TAG, "push");
 
         rateLimitChallengeManager.answerPushChallenge(auth.getAccount(), pushChallengeRequest.getChallenge());
       } else if (answerRequest instanceof AnswerRecaptchaChallengeRequest) {
-        try {
+        tags = tags.and(CHALLENGE_TYPE_TAG, "recaptcha");
 
+        try {
           final AnswerRecaptchaChallengeRequest recaptchaChallengeRequest = (AnswerRecaptchaChallengeRequest) answerRequest;
           final String mostRecentProxy = ForwardedIpUtil.getMostRecentProxy(forwardedFor).orElseThrow();
 
@@ -59,9 +73,13 @@ public class ChallengeController {
         } catch (final NoSuchElementException e) {
           return Response.status(400).build();
         }
+      } else {
+        tags = tags.and(CHALLENGE_TYPE_TAG, "unrecognized");
       }
     } catch (final RateLimitExceededException e) {
       throw new RetryLaterException(e);
+    } finally {
+      Metrics.counter(CHALLENGE_RESPONSE_COUNTER_NAME, tags).increment();
     }
 
     return Response.status(200).build();