diff --git a/.dockerignore b/.dockerignore
new file mode 100644
index 0000000..1d37234
--- /dev/null
+++ b/.dockerignore
@@ -0,0 +1,26 @@
+# Build artifacts (cached in named volume instead)
+build-wasm/
+
+# Git internals (large, not needed for build)
+.git/modules/
+
+# Compiled files
+*.wasm
+*.o
+*.a
+*.o.tmp
+
+# Node modules (for tests)
+node_modules/
+
+# Output directory
+output/
+
+# IDE and editor files
+.idea/
+.vscode/
+*.swp
+*.swo
+
+# macOS
+.DS_Store
diff --git a/.gitignore b/.gitignore
index c937732..fc3a09f 100644
--- a/.gitignore
+++ b/.gitignore
@@ -37,6 +37,7 @@ wxwidgets-clean/
 /tests/node_modules/
 /tests/playwright-report/
 /tests/test-results/
+/tests/.test-port
 /test-results/
 /tests/wasm-app/*.js
 /tests/wasm-app/*.html
diff --git a/docker/Dockerfile b/docker/Dockerfile
new file mode 100644
index 0000000..69034be
--- /dev/null
+++ b/docker/Dockerfile
@@ -0,0 +1,25 @@
+# Use ARM64-native image for Apple Silicon (M1/M2/M3/M4)
+FROM emscripten/emsdk:4.0.2-arm64
+
+# Install build tools required for KiCad WASM build
+RUN apt-get update && apt-get install -y \
+    cmake \
+    autoconf \
+    automake \
+    libtool \
+    meson \
+    ninja-build \
+    pkg-config \
+    curl \
+    git \
+    python3 \
+    && rm -rf /var/lib/apt/lists/*
+
+WORKDIR /workspace
+
+# Entry point that sources Emscripten environment
+COPY docker/entrypoint.sh /entrypoint.sh
+RUN chmod +x /entrypoint.sh
+
+ENTRYPOINT ["/entrypoint.sh"]
+CMD ["bash"]
diff --git a/docker/README.md b/docker/README.md
new file mode 100644
index 0000000..c4e21fe
--- /dev/null
+++ b/docker/README.md
@@ -0,0 +1,96 @@
+# Docker Build Environment for KiCad WASM
+
+This directory contains Docker configuration for building KiCad for WebAssembly in a reproducible, isolated environment.
+
+## Prerequisites
+
+- Docker Desktop (with Docker Compose v2)
+- Git submodules initialized: `git submodule update --init --recursive`
+
+## Quick Start
+
+```bash
+# Build KiCad WASM (full build)
+./docker/build.sh
+
+# Build with options
+./docker/build.sh --no-clean    # Skip cleaning build directory
+./docker/build.sh --debug       # Build with debug symbols
+
+# Interactive shell for debugging
+./docker/shell.sh
+```
+
+## What Gets Built
+
+The build process includes:
+
+1. **Dependencies** (cached in Docker volume):
+   - GLM (header-only)
+   - Zstd, Protobuf
+   - FreeType, HarfBuzz
+   - Pixman, Cairo
+   - Boost (Locale)
+   - OpenCASCADE (optional, for 3D/STEP)
+   - CURL headers, libgit2 headers (stubs)
+
+2. **wxWidgets** (built from submodule)
+
+3. **KiCad PCBnew** (main application)
+
+## Container Resources
+
+Configured for M4 Max (adjust in docker-compose.yml):
+- CPUs: 10 cores
+- Memory: 16GB
+
+## Volume Strategy
+
+| Path | Type | Purpose |
+|------|------|---------|
+| `/workspace` | Bind mount | Source code |
+| `/workspace/build-wasm` | Named volume | Build cache (deps, sysroot) |
+| `/workspace/output` | Bind mount | Final WASM output |
+
+## Common Commands
+
+```bash
+# Start container
+docker compose -f docker/docker-compose.yml up -d
+
+# Run a command inside
+docker compose -f docker/docker-compose.yml exec kicad-wasm-builder <command>
+
+# View logs
+docker compose -f docker/docker-compose.yml logs -f
+
+# Stop container
+docker compose -f docker/docker-compose.yml down
+
+# Clear build cache (full rebuild)
+docker volume rm docker_kicad-build-cache
+```
+
+## Troubleshooting
+
+### Build freezes
+The OpenCASCADE build is very resource-intensive. If it freezes:
+1. Reduce parallel jobs: Edit script to use `-j4` instead of `-j$(nproc)`
+2. Monitor with `docker stats`
+3. Consider building OpenCASCADE separately with `./scripts/deps/build-opencascade.sh`
+
+### Permission issues
+Files created in container are owned by root. To fix:
+```bash
+sudo chown -R $(whoami) output/
+```
+
+### Cache issues
+```bash
+# Clear all cached builds
+docker volume rm docker_kicad-build-cache
+
+# Or clear specific stamps inside container
+./docker/shell.sh
+rm /workspace/build-wasm/stamps/*.stamp
+```
diff --git a/docker/build.sh b/docker/build.sh
new file mode 100755
index 0000000..d78f4f1
--- /dev/null
+++ b/docker/build.sh
@@ -0,0 +1,19 @@
+#!/bin/bash
+# Build KiCad WASM inside Docker container
+set -e
+
+cd "$(dirname "$0")/.."
+
+# Start container if not running
+docker compose -f docker/docker-compose.yml up -d
+
+# Run build command
+docker compose -f docker/docker-compose.yml exec kicad-wasm-builder \
+    /workspace/scripts/kicad/build-pcbnew.sh "$@"
+
+# Copy output to host-accessible directory
+echo "Copying build output to ./output/..."
+docker compose -f docker/docker-compose.yml exec kicad-wasm-builder \
+    bash -c "mkdir -p /workspace/output && cp -r /workspace/build-wasm/kicad-pcbnew/bin/* /workspace/output/ 2>/dev/null || true"
+
+echo "Build complete. Output files in ./output/"
diff --git a/docker/docker-compose.yml b/docker/docker-compose.yml
new file mode 100644
index 0000000..8d68d41
--- /dev/null
+++ b/docker/docker-compose.yml
@@ -0,0 +1,28 @@
+services:
+  kicad-wasm-builder:
+    build:
+      context: ..
+      dockerfile: docker/Dockerfile
+    container_name: kicad-wasm-builder
+
+    # Resource limits (M4 Max: 10 cores, 16GB)
+    deploy:
+      resources:
+        limits:
+          cpus: '10'
+          memory: 16G
+
+    volumes:
+      # Source code (read-write for git operations)
+      - ..:/workspace:cached
+      # Named volume for build cache (faster than bind mount on macOS)
+      - kicad-build-cache:/workspace/build-wasm
+      # Output directory for easy access to final WASM files
+      - ../output:/workspace/output
+
+    # Keep container running for interactive use
+    stdin_open: true
+    tty: true
+
+volumes:
+  kicad-build-cache:
diff --git a/docker/entrypoint.sh b/docker/entrypoint.sh
new file mode 100755
index 0000000..747d2ec
--- /dev/null
+++ b/docker/entrypoint.sh
@@ -0,0 +1,8 @@
+#!/bin/bash
+set -e
+
+# Source Emscripten environment
+source /emsdk/emsdk_env.sh 2>/dev/null
+
+# Execute command or start shell
+exec "$@"
diff --git a/docker/shell.sh b/docker/shell.sh
new file mode 100755
index 0000000..ab2f3a6
--- /dev/null
+++ b/docker/shell.sh
@@ -0,0 +1,11 @@
+#!/bin/bash
+# Open interactive shell in build container for debugging
+set -e
+
+cd "$(dirname "$0")/.."
+
+# Start container if not running
+docker compose -f docker/docker-compose.yml up -d
+
+# Open interactive shell
+docker compose -f docker/docker-compose.yml exec kicad-wasm-builder bash
diff --git a/tests/playwright.config.ts b/tests/playwright.config.ts
index a0c8ef7..d546fef 100644
--- a/tests/playwright.config.ts
+++ b/tests/playwright.config.ts
@@ -1,4 +1,49 @@
 import { defineConfig, devices } from '@playwright/test';
+import { execSync } from 'child_process';
+import * as fs from 'fs';
+import * as path from 'path';
+
+const PORT_FILE = path.join(__dirname, '.test-port');
+
+// Get existing port from file or find a new one
+// This ensures all workers use the same port
+function getOrFindPort(): number {
+  // Check if port file exists and is recent (created in last 60 seconds)
+  try {
+    const stat = fs.statSync(PORT_FILE);
+    const age = Date.now() - stat.mtimeMs;
+    if (age < 60000) {
+      const port = parseInt(fs.readFileSync(PORT_FILE, 'utf-8').trim());
+      if (port > 0 && port < 65536) {
+        return port;
+      }
+    }
+  } catch {
+    // File doesn't exist or can't be read
+  }
+
+  // Find a new free port
+  const port = findFreePort();
+  fs.writeFileSync(PORT_FILE, port.toString());
+  return port;
+}
+
+// Find a free port dynamically using a shell command
+function findFreePort(): number {
+  // Use Python to find a free port (works on macOS and Linux)
+  try {
+    const result = execSync(
+      'python3 -c "import socket; s=socket.socket(); s.bind((\'\',0)); print(s.getsockname()[1]); s.close()"',
+      { encoding: 'utf-8' }
+    );
+    return parseInt(result.trim());
+  } catch {
+    // Fallback to default port range
+    return 9000 + Math.floor(Math.random() * 1000);
+  }
+}
+
+const port = getOrFindPort();
 
 export default defineConfig({
   testDir: './e2e',
@@ -13,7 +58,7 @@ export default defineConfig({
   testIgnore: ['**/button-finder.spec.ts'],
 
   use: {
-    baseURL: 'http://localhost:8080',
+    baseURL: `http://localhost:${port}`,
     trace: 'on-first-retry',
     // Grant clipboard and font permissions for tests
     permissions: ['clipboard-read', 'clipboard-write', 'local-fonts'],
@@ -27,8 +72,8 @@ export default defineConfig({
   ],
 
   webServer: {
-    command: 'npx serve wasm-app -p 8080',
-    port: 8080,
+    command: `npx serve wasm-app -p ${port}`,
+    port: port,
     reuseExistingServer: !process.env.CI,
   },
 });