diff --git a/flake.nix b/flake.nix
index 0ecbc89..58e5046 100644
--- a/flake.nix
+++ b/flake.nix
@@ -148,7 +148,7 @@
             pnpmDeps = (pkgs.fetchPnpmDeps.override { pnpm = pkgs.pnpm_10; }) {
               inherit (finalAttrs) pname version src;
               fetcherVersion = 3;
-              hash = "sha256-hOqiAbnjKsoQnV8lgto5HspDsLIb+48sNLkShIjCZPQ=";
+              hash = "sha256-AzF/rrhqbvl613hNsC18YSylBSVxtatg7fEiUEF1u2o=";
             };
 
             buildPhase = ''
diff --git a/web/package.json b/web/package.json
index f496bbf..97d0369 100644
--- a/web/package.json
+++ b/web/package.json
@@ -6,7 +6,7 @@
   "packageManager": "pnpm@9.15.4",
   "scripts": {
     "dev": "vite",
-    "build": "tsc -b && vite build",
+    "build": "tsc -b tsconfig.build.json && vite build",
     "preview": "vite preview",
     "typecheck": "tsc -b --noEmit",
     "test": "vitest run",
diff --git a/web/tsconfig.build.json b/web/tsconfig.build.json
new file mode 100644
index 0000000..88cd2cf
--- /dev/null
+++ b/web/tsconfig.build.json
@@ -0,0 +1,8 @@
+{
+  // The nix derivation's src is `./web`, so the shared fixtures/ directory at
+  // the repo root does not exist there and `*.test.ts` cannot resolve its
+  // imports. Tests are not part of the shipped bundle; `pnpm typecheck` still
+  // checks them from a full checkout.
+  "extends": "./tsconfig.json",
+  "exclude": ["src/**/*.test.ts", "src/**/*.test.tsx"]
+}