diff --git a/package.json b/package.json
index 6529702f..dd579a42 100644
--- a/package.json
+++ b/package.json
@@ -35,7 +35,7 @@
     "@bazel/hide-bazel-files": "~0.38.2",
     "@bazel/karma": "~0.33.1",
     "@bazel/typescript": "~0.33.1",
-    "@improbable-eng/grpc-web": "^0.9.1",
+    "@improbable-eng/grpc-web": "^0.12.0",
     "@types/chai": "^4.2.3",
     "@types/google-protobuf": "^3.2.7",
     "@types/jasmine": "^3.4.4",
diff --git a/yarn.lock b/yarn.lock
index b50f680f..5a08f671 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -50,9 +50,10 @@
     source-map-support "0.5.9"
     tsutils "2.27.2"
 
-"@improbable-eng/grpc-web@^0.9.1":
-  version "0.9.1"
-  resolved "https://registry.yarnpkg.com/@improbable-eng/grpc-web/-/grpc-web-0.9.1.tgz#61a36fb04f6f2a202fe01b3a35d1fc891cc93933"
+"@improbable-eng/grpc-web@^0.12.0":
+  version "0.12.0"
+  resolved "https://registry.yarnpkg.com/@improbable-eng/grpc-web/-/grpc-web-0.12.0.tgz#9b10a7edf2a1d7672f8997e34a60e7b70e49738f"
+  integrity sha512-uJjgMPngreRTYPBuo6gswMj1gK39Wbqre/RgE0XnSDXJRg6ST7ZhuS53dFE6Vc2CX4jxgl+cO+0B3op8LA4Q0Q==
   dependencies:
     browser-headers "^0.4.0"
 
@@ -369,11 +370,7 @@ braces@^2.3.1, braces@^2.3.2:
     split-string "^3.0.2"
     to-regex "^3.0.1"
 
-browser-headers@^0.4.0:
-  version "0.4.0"
-  resolved "https://registry.yarnpkg.com/browser-headers/-/browser-headers-0.4.0.tgz#7b6b4d3cc0cecc9ddf503768147932105c421734"
-
-browser-headers@^0.4.1:
+browser-headers@^0.4.0, browser-headers@^0.4.1:
   version "0.4.1"
   resolved "https://registry.yarnpkg.com/browser-headers/-/browser-headers-0.4.1.tgz#4308a7ad3b240f4203dbb45acedb38dc2d65dd02"