diff --git a/src/main/java/com/cloudbees/jenkins/plugins/bitbucket/filesystem/BitbucketSCMFileSystem.java b/src/main/java/com/cloudbees/jenkins/plugins/bitbucket/filesystem/BitbucketSCMFileSystem.java
index a69bf0ab3..e9d3df97f 100644
--- a/src/main/java/com/cloudbees/jenkins/plugins/bitbucket/filesystem/BitbucketSCMFileSystem.java
+++ b/src/main/java/com/cloudbees/jenkins/plugins/bitbucket/filesystem/BitbucketSCMFileSystem.java
@@ -32,6 +32,7 @@
 import com.cloudbees.jenkins.plugins.bitbucket.api.BitbucketApi;
 import com.cloudbees.jenkins.plugins.bitbucket.api.BitbucketApiFactory;
 import com.cloudbees.jenkins.plugins.bitbucket.api.BitbucketAuthenticator;
+import com.cloudbees.jenkins.plugins.bitbucket.client.BitbucketCloudApiClient;
 import com.cloudbees.plugins.credentials.CredentialsMatchers;
 import com.cloudbees.plugins.credentials.CredentialsProvider;
 import com.cloudbees.plugins.credentials.common.StandardCredentials;
@@ -139,17 +140,36 @@ public SCMFileSystem build(@NonNull SCMSource source, @NonNull SCMHead head, @Ch
             BitbucketAuthenticator authenticator = AuthenticationTokens.convert(BitbucketAuthenticator.authenticationContext(serverUrl), credentials);
 
             BitbucketApi apiClient = BitbucketApiFactory.newInstance(serverUrl, authenticator, owner, repository);
-            String ref;
+            String ref = null;
+
             if (head instanceof BranchSCMHead) {
                 ref = head.getName();
             } else if (head instanceof PullRequestSCMHead) {
+                // working on a pull request - can be either "HEAD" or "MERGE"
                 PullRequestSCMHead pr = (PullRequestSCMHead) head;
-                if (!(pr.getCheckoutStrategy() == ChangeRequestCheckoutStrategy.MERGE) && pr.getRepository() != null) {
-                    return new BitbucketSCMFileSystem(apiClient, pr.getOriginName(), rev);
+                if (pr.getRepository() == null) { // check access to repository (might be forked)
+                    return null;
+                }
+
+                if (apiClient instanceof BitbucketCloudApiClient) {
+                    // support lightweight checkout for branches with same owner and repository
+                    if (pr.getCheckoutStrategy() == ChangeRequestCheckoutStrategy.HEAD &&
+                        pr.getRepoOwner().equals(src.getRepoOwner()) &&
+                        pr.getRepository().equals(src.getRepository())) {
+                        ref = pr.getOriginName();
+                    } else {
+                        // Bitbucket cloud does not support refs for pull requests
+                        // Makes lightweight checkout for forks and merge strategy improbable
+                        // TODO waiting for cloud support: https://bitbucket.org/site/master/issues/5814/refify-pull-requests-by-making-them-a-ref
+                        return null;
+                    }
+                } else if (pr.getCheckoutStrategy() == ChangeRequestCheckoutStrategy.HEAD) {
+                    ref = "pull-requests/" + pr.getId() + "/from";
+                } else if (pr.getCheckoutStrategy() == ChangeRequestCheckoutStrategy.MERGE) {
+                    ref = "pull-requests/" + pr.getId() + "/merge";
                 }
-                return null; // TODO support merge revisions somehow
             } else if (head instanceof BitbucketTagSCMHead) {
-                 ref = "tags/" + head.getName();
+                ref = "tags/" + head.getName();
             } else {
                 return null;
             }
diff --git a/src/main/java/com/cloudbees/jenkins/plugins/bitbucket/server/client/BitbucketServerAPIClient.java b/src/main/java/com/cloudbees/jenkins/plugins/bitbucket/server/client/BitbucketServerAPIClient.java
index bc4299f93..d05a838d2 100644
--- a/src/main/java/com/cloudbees/jenkins/plugins/bitbucket/server/client/BitbucketServerAPIClient.java
+++ b/src/main/java/com/cloudbees/jenkins/plugins/bitbucket/server/client/BitbucketServerAPIClient.java
@@ -147,7 +147,7 @@ public BitbucketCommit call() throws Exception {
     private static final String API_PULL_REQUESTS_PATH = API_REPOSITORY_PATH + "/pull-requests{?start,limit,at,direction,state}";
     private static final String API_PULL_REQUEST_PATH = API_REPOSITORY_PATH + "/pull-requests/{id}";
     private static final String API_PULL_REQUEST_MERGE_PATH = API_REPOSITORY_PATH + "/pull-requests/{id}/merge";
-    private static final String API_BROWSE_PATH = API_REPOSITORY_PATH + "/browse{/path*}{?at}";
+    static final String API_BROWSE_PATH = API_REPOSITORY_PATH + "/browse/{+path}{?at}";
     private static final String API_COMMITS_PATH = API_REPOSITORY_PATH + "/commits{/hash}";
     private static final String API_PROJECT_PATH = API_BASE_PATH + "/projects/{owner}";
     private static final String API_COMMIT_COMMENT_PATH = API_REPOSITORY_PATH + "/commits{/hash}/comments";
diff --git a/src/test/java/com/cloudbees/jenkins/plugins/bitbucket/server/client/BitbucketServerAPIClientTest.java b/src/test/java/com/cloudbees/jenkins/plugins/bitbucket/server/client/BitbucketServerAPIClientTest.java
new file mode 100644
index 000000000..979e42ef5
--- /dev/null
+++ b/src/test/java/com/cloudbees/jenkins/plugins/bitbucket/server/client/BitbucketServerAPIClientTest.java
@@ -0,0 +1,34 @@
+package com.cloudbees.jenkins.plugins.bitbucket.server.client;
+
+import com.damnhandy.uri.template.UriTemplate;
+import org.junit.Assert;
+import org.junit.Test;
+
+import static com.cloudbees.jenkins.plugins.bitbucket.server.client.BitbucketServerAPIClient.API_BROWSE_PATH;
+
+public class BitbucketServerAPIClientTest {
+
+    @Test
+    public void repoBrowsePathFolder() {
+        String expand = UriTemplate
+            .fromTemplate(API_BROWSE_PATH)
+            .set("owner", "test")
+            .set("repo", "test")
+            .set("path", "folder/Jenkinsfile")
+            .set("at", "fix/test")
+            .expand();
+        Assert.assertEquals("/rest/api/1.0/projects/test/repos/test/browse/folder/Jenkinsfile?at=fix%2Ftest", expand);
+    }
+
+    @Test
+    public void repoBrowsePathFile() {
+        String expand = UriTemplate
+            .fromTemplate(API_BROWSE_PATH)
+            .set("owner", "test")
+            .set("repo", "test")
+            .set("path", "Jenkinsfile")
+            .expand();
+        Assert.assertEquals("/rest/api/1.0/projects/test/repos/test/browse/Jenkinsfile", expand);
+    }
+
+}