diff --git a/src/main/java/com/google/devtools/build/lib/remote/SimpleBlobStoreActionCache.java b/src/main/java/com/google/devtools/build/lib/remote/SimpleBlobStoreActionCache.java
index 1c4c462..645a693 100644
--- a/src/main/java/com/google/devtools/build/lib/remote/SimpleBlobStoreActionCache.java
+++ b/src/main/java/com/google/devtools/build/lib/remote/SimpleBlobStoreActionCache.java
@@ -180,7 +180,7 @@
       Digest stdout = uploadFileContents(outErr.getOutputPath());
       result.setStdoutDigest(stdout);
     }
-    blobStore.put(
+    blobStore.putActionResult(
         actionKey.getDigest().getHash(), new ByteArrayInputStream(result.build().toByteArray()));
   }
 
@@ -269,7 +269,7 @@
     return digest;
   }
 
-  public void downloadBlob(Digest digest, OutputStream out)
+  private void downloadBlob(Digest digest, OutputStream out)
       throws IOException, InterruptedException {
     if (digest.getSizeBytes() == 0) {
       return;
@@ -300,18 +300,31 @@
   public ActionResult getCachedActionResult(ActionKey actionKey)
       throws IOException, InterruptedException {
     try {
-      byte[] data = downloadBlob(actionKey.getDigest());
+      byte[] data = downloadActionResult(actionKey.getDigest());
       return ActionResult.parseFrom(data);
-    } catch (InvalidProtocolBufferException e) {
-      return null;
-    } catch (CacheNotFoundException e) {
+    } catch (InvalidProtocolBufferException | CacheNotFoundException e) {
       return null;
     }
   }
 
+  private byte[] downloadActionResult(Digest digest) throws IOException, InterruptedException {
+    if (digest.getSizeBytes() == 0) {
+      return new byte[0];
+    }
+    // This unconditionally downloads the whole blob into memory!
+    checkBlobSize(digest.getSizeBytes() / 1024, "Download Action Result");
+    ByteArrayOutputStream out = new ByteArrayOutputStream();
+    boolean success = blobStore.getActionResult(digest.getHash(), out);
+    if (!success) {
+      throw new CacheNotFoundException(digest);
+    }
+    return out.toByteArray();
+  }
+
   public void setCachedActionResult(ActionKey actionKey, ActionResult result)
       throws IOException, InterruptedException {
-    blobStore.put(actionKey.getDigest().getHash(), new ByteArrayInputStream(result.toByteArray()));
+    blobStore.putActionResult(actionKey.getDigest().getHash(),
+        new ByteArrayInputStream(result.toByteArray()));
   }
 
   @Override
diff --git a/src/main/java/com/google/devtools/build/lib/remote/blobstore/ConcurrentMapBlobStore.java b/src/main/java/com/google/devtools/build/lib/remote/blobstore/ConcurrentMapBlobStore.java
index 179385c..82cd36b 100644
--- a/src/main/java/com/google/devtools/build/lib/remote/blobstore/ConcurrentMapBlobStore.java
+++ b/src/main/java/com/google/devtools/build/lib/remote/blobstore/ConcurrentMapBlobStore.java
@@ -43,11 +43,23 @@
   }
 
   @Override
+  public boolean getActionResult(String key, OutputStream out)
+      throws IOException, InterruptedException {
+    return get(key, out);
+  }
+
+  @Override
   public void put(String key, InputStream in) throws IOException {
     byte[] value = ByteStreams.toByteArray(in);
     map.put(key, value);
   }
 
   @Override
+  public void putActionResult(String key, InputStream in)
+      throws IOException, InterruptedException {
+    put(key, in);
+  }
+
+  @Override
   public void close() {}
 }
\ No newline at end of file
diff --git a/src/main/java/com/google/devtools/build/lib/remote/blobstore/OnDiskBlobStore.java b/src/main/java/com/google/devtools/build/lib/remote/blobstore/OnDiskBlobStore.java
index 8e78055..8d41023 100644
--- a/src/main/java/com/google/devtools/build/lib/remote/blobstore/OnDiskBlobStore.java
+++ b/src/main/java/com/google/devtools/build/lib/remote/blobstore/OnDiskBlobStore.java
@@ -46,6 +46,12 @@
   }
 
   @Override
+  public boolean getActionResult(String key, OutputStream out)
+      throws IOException, InterruptedException {
+    return get(key, out);
+  }
+
+  @Override
   public void put(String key, InputStream in) throws IOException {
     // Write a temporary file first, and then rename, to avoid data corruption in case of a crash.
     Path temp = toPath(UUID.randomUUID().toString());
@@ -59,6 +65,11 @@
   }
 
   @Override
+  public void putActionResult(String key, InputStream in) throws IOException, InterruptedException {
+    put(key, in);
+  }
+
+  @Override
   public void close() {}
 
   private Path toPath(String key) {
diff --git a/src/main/java/com/google/devtools/build/lib/remote/blobstore/RestBlobStore.java b/src/main/java/com/google/devtools/build/lib/remote/blobstore/RestBlobStore.java
index 82e9b47..b7473d8 100644
--- a/src/main/java/com/google/devtools/build/lib/remote/blobstore/RestBlobStore.java
+++ b/src/main/java/com/google/devtools/build/lib/remote/blobstore/RestBlobStore.java
@@ -32,19 +32,22 @@
  * Implementation of {@link SimpleBlobStore} with a REST service. The REST service needs to
  * support the following HTTP methods.
  *
- * <p>PUT /cache/1234 HTTP/1.1 PUT method is used to upload a blob with a base16 key. In this
- * example the key is 1234. Valid status codes are 200, 201, 202 and 204.
+ * <p>PUT /{actioncache,cas}/1234 HTTP/1.1 PUT method is used to upload a blob with a base16 key.
+ * In this example the key is 1234. Valid status codes are 200, 201, 202 and 204.
  *
- * <p>GET /cache/1234 HTTP/1.1 GET method fetches a blob with the specified key. In this example
- * the key is 1234. A status code of 200 should be followed by the content of blob. Status code of
- * 404 or 204 means the key cannot be found.
+ * <p>GET /{actioncache,cas}/1234 HTTP/1.1 GET method fetches a blob with the specified key. In this
+ * example the key is 1234. A status code of 200 should be followed by the content of blob. Status
+ * code of 404 or 204 means the key cannot be found.
  *
- * <p>HEAD /cache/1234 HTTP/1.1 HEAD method checks to see if the specified key exists in the blob
- * store. A status code of 200 indicates the key is found in the blob store. A status code of 404
- * indicates the key is not found in the blob store.
+ * <p>HEAD /{actioncache,cas}/1234 HTTP/1.1 HEAD method checks to see if the specified key exists in
+ * the blob store. A status code of 200 indicates the key is found in the blob store. A status code
+ * of 404 indicates the key is not found in the blob store.
  */
 public final class RestBlobStore implements SimpleBlobStore {
 
+  private static final String ACTION_CACHE_PREFIX = "ac";
+  private static final String CAS_PREFIX = "cas";
+
   private final String baseUrl;
   private final PoolingHttpClientConnectionManager connMan;
   private final HttpClientBuilder clientFactory;
@@ -85,8 +88,18 @@
 
   @Override
   public boolean get(String key, OutputStream out) throws IOException {
+    return get(CAS_PREFIX, key, out);
+  }
+
+  @Override
+  public boolean getActionResult(String key, OutputStream out)
+      throws IOException, InterruptedException {
+    return get(ACTION_CACHE_PREFIX, key, out);
+  }
+
+  private boolean get(String urlPrefix, String key, OutputStream out) throws IOException {
     HttpClient client = clientFactory.build();
-    HttpGet get = new HttpGet(baseUrl + "/" + key);
+    HttpGet get = new HttpGet(baseUrl + "/" + urlPrefix + "/" + key);
     return client.execute(
         get,
         response -> {
@@ -105,8 +118,17 @@
 
   @Override
   public void put(String key, InputStream in) throws IOException {
+    put(CAS_PREFIX, key, in);
+  }
+
+  @Override
+  public void putActionResult(String key, InputStream in) throws IOException, InterruptedException {
+    put(ACTION_CACHE_PREFIX, key, in);
+  }
+
+  private void put(String urlPrefix, String key, InputStream in) throws IOException {
     HttpClient client = clientFactory.build();
-    HttpPut put = new HttpPut(baseUrl + "/" + key);
+    HttpPut put = new HttpPut(baseUrl + "/" + urlPrefix + "/" + key);
     // For now, upload a byte array instead of a stream, due to Hazelcast crashing on the stream.
     // See https://github.com/hazelcast/hazelcast/issues/10878.
     put.setEntity(new ByteArrayEntity(ByteStreams.toByteArray(in)));
diff --git a/src/main/java/com/google/devtools/build/lib/remote/blobstore/SimpleBlobStore.java b/src/main/java/com/google/devtools/build/lib/remote/blobstore/SimpleBlobStore.java
index 5f79c45..3847996 100644
--- a/src/main/java/com/google/devtools/build/lib/remote/blobstore/SimpleBlobStore.java
+++ b/src/main/java/com/google/devtools/build/lib/remote/blobstore/SimpleBlobStore.java
@@ -19,25 +19,42 @@
 import java.io.OutputStream;
 
 /**
- * A simple interface for storing blobs (in the form of byte arrays) each one indexed by a
- * hexadecimal string. Implementation must be thread-safe.
+ * An interface for storing BLOBs each one indexed by a string (hash in hexadecimal).
+ *
+ * <p>Implementations must be thread-safe.
  */
 public interface SimpleBlobStore {
-  /** Returns true if the provided {@code key} is stored in the blob store. */
+  /**
+   * Returns {@code key} if the provided {@code key} is stored in the CAS.
+   */
   boolean containsKey(String key) throws IOException, InterruptedException;
 
   /**
-   * Returns the blob (in the form of a byte array) indexed by {@code key}. Returns null if the
-   * {@code key} cannot be found.
+   * Fetches the BLOB associated with the {@code key} from the CAS and writes it to {@code out}.
+   *
+   * @return {@code true} if the {@code key} was found. {@code false} otherwise.
    */
   boolean get(String key, OutputStream out) throws IOException, InterruptedException;
 
   /**
-   * Uploads a blob (as {@code value}) indexed by {@code key} to the blob store. Existing blob
-   * indexed by the same {@code key} will be overwritten.
+   * Fetches the BLOB associated with the {@code key} from the Action Cache and writes it to
+   * {@code out}.
+   *
+   * @return {@code true} if the {@code key} was found. {@code false} otherwise.
+   */
+  boolean getActionResult(String actionKey, OutputStream out) throws IOException,
+      InterruptedException;
+
+  /**
+   * Uploads a BLOB (as {@code in}) indexed by {@code key} to the CAS.
    */
   void put(String key, InputStream in) throws IOException, InterruptedException;
 
+  /**
+   * Uploads a BLOB (as {@code in}) indexed by {@code key} to the Action Cache.
+   */
+  void putActionResult(String actionKey, InputStream in) throws IOException, InterruptedException;
+
   /** Close resources associated with the blob store. */
   void close();
 }