diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index e175b10c8924e..95db591412625 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -40,7 +40,7 @@ variables:
 .docker-env:                       &docker-env
   retry:
     max: 2
-    when: 
+    when:
       - runner_system_failure
       - unknown_failure
       - api_failure
@@ -131,6 +131,23 @@ test-linux-stable:                 &test
     - sccache -s
 
 
+check-web-wasm:                    &test
+  stage:                           test
+  <<:                              *test-refs
+  <<:                              *docker-env
+  <<:                              *compiler_info
+  script:
+    # WASM support is in progress. As more and more crates support WASM, we
+    # should add entries here. See https://github.com/paritytech/polkadot/issues/625
+    - time cargo build --locked --target=wasm32-unknown-unknown --manifest-path availability-store/Cargo.toml
+    - time cargo build --locked --target=wasm32-unknown-unknown --manifest-path executor/Cargo.toml
+    - time cargo build --locked --target=wasm32-unknown-unknown --manifest-path erasure-coding/Cargo.toml
+    - time cargo build --locked --target=wasm32-unknown-unknown --manifest-path parachain/Cargo.toml
+    - time cargo build --locked --target=wasm32-unknown-unknown --manifest-path primitives/Cargo.toml
+    - time cargo build --locked --target=wasm32-unknown-unknown --manifest-path rpc/Cargo.toml
+    - time cargo build --locked --target=wasm32-unknown-unknown --manifest-path runtime/Cargo.toml
+    - time cargo build --locked --target=wasm32-unknown-unknown --manifest-path statement-table/Cargo.toml
+    - sccache -s
 
 
 build-linux-release:               &build
@@ -209,7 +226,7 @@ publish-docker-release:
     - docker build
       --build-arg VCS_REF="${CI_COMMIT_SHA}"
       --build-arg BUILD_DATE="$(date -u '+%Y-%m-%dT%H:%M:%SZ')"
-      --tag $CONTAINER_IMAGE:$VERSION 
+      --tag $CONTAINER_IMAGE:$VERSION
       --tag $CONTAINER_IMAGE:$EXTRATAG .
     - docker push $CONTAINER_IMAGE:$VERSION
     - docker push $CONTAINER_IMAGE:$EXTRATAG
diff --git a/availability-store/Cargo.toml b/availability-store/Cargo.toml
index 011d6de084998..2c76666686bae 100644
--- a/availability-store/Cargo.toml
+++ b/availability-store/Cargo.toml
@@ -12,5 +12,7 @@ log = "0.4.8"
 codec = { package = "parity-scale-codec", version = "1.1.0", default-features = false, features = ["derive"] }
 substrate-primitives = { git = "https://github.com/paritytech/substrate", branch = "polkadot-master" }
 kvdb = "0.1.1"
-kvdb-rocksdb = "0.2"
 kvdb-memorydb = "0.1.2"
+
+[target.'cfg(not(target_os = "unknown"))'.dependencies]
+kvdb-rocksdb = "0.2"
diff --git a/availability-store/src/lib.rs b/availability-store/src/lib.rs
index 0e2cee18252ad..9053bc67dc9c5 100644
--- a/availability-store/src/lib.rs
+++ b/availability-store/src/lib.rs
@@ -22,7 +22,6 @@
 
 use codec::{Encode, Decode};
 use kvdb::{KeyValueDB, DBTransaction};
-use kvdb_rocksdb::{Database, DatabaseConfig};
 use polkadot_primitives::Hash;
 use polkadot_primitives::parachain::{Id as ParaId, BlockData, Message};
 use log::warn;
@@ -74,7 +73,9 @@ pub struct Store {
 
 impl Store {
 	/// Create a new `Store` with given config on disk.
+	#[cfg(not(target_os = "unknown"))]
 	pub fn new(config: Config) -> io::Result<Self> {
+		use kvdb_rocksdb::{Database, DatabaseConfig};
 		let mut db_config = DatabaseConfig::with_columns(Some(columns::NUM_COLUMNS));
 
 		if let Some(cache_size) = config.cache_size {