diff --git a/.envrc b/.envrc
index 3550a30..0cd1325 100644
--- a/.envrc
+++ b/.envrc
@@ -1 +1 @@
-use flake
+use flake '.?submodules=1'
diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
new file mode 100644
index 0000000..7164788
--- /dev/null
+++ b/.github/workflows/build.yml
@@ -0,0 +1,51 @@
+name: Build
+
+on:
+  push:
+    branches: [ main ]
+  pull_request:
+    branches:
+      - "**"
+    paths-ignore:
+      - '*.md'
+  workflow_dispatch:
+
+# This allows a subsequently queued workflow run to interrupt previous runs on pull-requests
+concurrency:
+  group: '${{ github.workflow }} @ ${{ github.event.pull_request.head.label || github.head_ref || github.run_id }}'
+  cancel-in-progress: true
+
+env:
+  CARGO_TERM_COLOR: always
+  CARGO_INCREMENTAL: 0
+  CARGO_NET_RETRY: 10
+  RUST_BACKTRACE: short
+  # We allow redundant explicit links because `cargo rdme` doesn't know how to resolve implicit intra-crate links.
+  RUSTDOCFLAGS: -A rustdoc::redundant_explicit_links -D warnings
+  # We will re-enable this once the client worker builds without warnings.
+  # RUSTFLAGS: -D warnings
+  RUSTUP_MAX_RETRIES: 10
+  RUST_LOG: warn
+
+permissions:
+  contents: read
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v4
+      with:
+        submodules: true
+    - uses: cachix/install-nix-action@v26
+    - uses: DeterminateSystems/magic-nix-cache-action@main
+    - name: Build the client worker
+      run: |
+        cd client-worker
+        nix develop '.?submodules=1' --override-input linera-protocol ../linera-protocol --command wasm-pack build --target web
+    - name: Build the extension
+      run: |
+        cd extension
+        nix develop --override-input linera-protocol ../linera-protocol --command pnpm install
+        nix develop --override-input linera-protocol ../linera-protocol --command pnpm build
diff --git a/.gitmodules b/.gitmodules
index bbe3307..9523c14 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -1,3 +1,3 @@
 [submodule "linera-protocol"]
 	path = linera-protocol
-	url = git@github.com:linera-io/linera-protocol
+	url = https://github.com/linera-io/linera-protocol
diff --git a/client-worker/src/lib.rs b/client-worker/src/lib.rs
index 64fdca1..ac8e113 100644
--- a/client-worker/src/lib.rs
+++ b/client-worker/src/lib.rs
@@ -91,6 +91,7 @@ impl ClientContext {
             chain.timestamp,
             chain.next_block_height,
             chain.pending_block.clone(),
+            chain.pending_blobs.clone(),
         )
     }
 
@@ -108,6 +109,7 @@ impl ClientContext {
                 timestamp,
                 next_block_height: BlockHeight::ZERO,
                 pending_block: None,
+                pending_blobs: BTreeMap::default(),
             });
         }
     }
diff --git a/client-worker/src/wallet.rs b/client-worker/src/wallet.rs
index 3dccd69..7643cdf 100644
--- a/client-worker/src/wallet.rs
+++ b/client-worker/src/wallet.rs
@@ -6,8 +6,8 @@ use std::collections::{BTreeMap, HashMap};
 use anyhow::Context as _;
 use linera_base::{
     crypto::{CryptoHash, CryptoRng, KeyPair, PublicKey},
-    data_types::{BlockHeight, Timestamp},
-    identifiers::{ChainDescription, ChainId, Owner},
+    data_types::{BlockHeight, HashedBlob, Timestamp},
+    identifiers::{BlobId, ChainDescription, ChainId, Owner},
 };
 use linera_chain::data_types::Block;
 use linera_core::{client::ChainClient, node::LocalValidatorNodeProvider};
@@ -137,6 +137,7 @@ impl Wallet {
             timestamp,
             next_block_height: BlockHeight(0),
             pending_block: None,
+            pending_blobs: BTreeMap::default(),
         };
         self.insert(user_chain);
         Ok(())
@@ -168,6 +169,7 @@ impl Wallet {
                 next_block_height: state.next_block_height(),
                 timestamp: state.timestamp(),
                 pending_block: state.pending_block().clone(),
+                pending_blobs: state.pending_blobs().clone(),
             },
         );
     }
@@ -199,6 +201,7 @@ pub struct UserChain {
     pub timestamp: Timestamp,
     pub next_block_height: BlockHeight,
     pub pending_block: Option<Block>,
+    pub pending_blobs: BTreeMap<BlobId, HashedBlob>,
 }
 
 impl UserChain {
@@ -216,6 +219,7 @@ impl UserChain {
             timestamp,
             next_block_height: BlockHeight::ZERO,
             pending_block: None,
+            pending_blobs: BTreeMap::default(),
         }
     }
 
@@ -227,6 +231,7 @@ impl UserChain {
             timestamp: self.timestamp.clone(),
             next_block_height: self.next_block_height.clone(),
             pending_block: self.pending_block.clone(),
+            pending_blobs: self.pending_blobs.clone(),
         }
     }
 
@@ -240,6 +245,7 @@ impl UserChain {
             timestamp,
             next_block_height: BlockHeight::ZERO,
             pending_block: None,
+            pending_blobs: BTreeMap::default(),
         }
     }
 }
diff --git a/flake.lock b/flake.lock
index ac5672f..0e025ca 100644
--- a/flake.lock
+++ b/flake.lock
@@ -82,17 +82,14 @@
         "treefmt-nix": "treefmt-nix"
       },
       "locked": {
-        "lastModified": 1715784324,
+        "lastModified": 1,
         "narHash": "sha256-G7I7bdzkHd3MvK2HJ2Wic1Q7EN70Fr/lo1SSY6nBmF0=",
-        "ref": "91b1bb47ec7f69a915846f985948ee07726e8ecc",
-        "rev": "91b1bb47ec7f69a915846f985948ee07726e8ecc",
-        "revCount": 3136,
-        "type": "git",
-        "url": "file:linera-protocol?shallow=1&submodules=1"
+        "path": "linera-protocol",
+        "type": "path"
       },
       "original": {
-        "type": "git",
-        "url": "file:linera-protocol?shallow=1&submodules=1"
+        "path": "linera-protocol",
+        "type": "path"
       }
     },
     "nixpkgs": {
diff --git a/flake.nix b/flake.nix
index 39b07d6..75338c1 100644
--- a/flake.nix
+++ b/flake.nix
@@ -3,10 +3,7 @@
     nixpkgs.url = "github:nixos/nixpkgs/nixos-unstable";
     flake-parts.url = "github:hercules-ci/flake-parts";
     systems.url = "github:nix-systems/default";
-    linera-protocol = {
-      type = "git";
-      url = "file:linera-protocol?shallow=1&submodules=1";
-    };
+    linera-protocol.url = "path:linera-protocol";
   };
 
   outputs = inputs: inputs.flake-parts.lib.mkFlake { inherit inputs; } {
diff --git a/linera-protocol b/linera-protocol
index 91b1bb4..11f9838 160000
--- a/linera-protocol
+++ b/linera-protocol
@@ -1 +1 @@
-Subproject commit 91b1bb47ec7f69a915846f985948ee07726e8ecc
+Subproject commit 11f9838ca7bd037490a84d905c8909c109f01895