@@ -10,6 +10,7 @@ A minimal, fast, JSON-LD native Solid server.
 
 - **Passkey Authentication** - WebAuthn/FIDO2 passwordless login with Touch ID, Face ID, or security keys
 - **HTTP Range Requests** - Partial content delivery for large files and media streaming
+- **LWS Protocol Mode (DRAFT)** - Optional W3C Linked Web Storage semantics (`--lws-mode` flag, see #87)
 - **Single-User Mode** - Simplified setup for personal pod servers
 - **ActivityPub Federation** - Fediverse integration with WebFinger, inbox/outbox, HTTP signatures
 - **LDP CRUD Operations** - GET, PUT, POST, DELETE, HEAD
@@ -301,6 +302,7 @@ createServer({
   logger: true,        // Enable Fastify logging (default: true)
   conneg: false,       // Enable content negotiation (default: false)
   notifications: false, // Enable WebSocket notifications (default: false)
+  lwsMode: false,      // Enable LWS protocol mode - DRAFT (default: false)
   subdomains: false,   // Enable subdomain-based pods (default: false)
   baseDomain: null,    // Base domain for subdomains (e.g., "example.com")
   mashlib: false,      // Enable Mashlib data browser - local mode (default: false)
@@ -349,6 +351,50 @@ Serves a modern Nextcloud-style UI shell while reusing mashlib's data layer. The
 
 Requires solidos-ui dist files in `src/mashlib-local/dist/solidos-ui/`. See [solidos-ui](https://github.com/solidos/solidos/tree/main/workspaces/solidos-ui) for details.
 
+### LWS Protocol Mode (DRAFT)
+
+⚠️ **Experimental Feature** - See [issue #87](https://github.com/JavaScriptSolidServer/JavaScriptSolidServer/issues/87) for full details.
+
+Enable W3C Linked Web Storage protocol semantics:
+
+```bash
+jss start --lws-mode
+```
+
+**Key Differences from Solid/LDP:**
+
+| Aspect | Solid/LDP (Default) | LWS Mode |
+|--------|-------------------|----------|
+| Resource Creation | PUT or POST | PUT or POST (POST+Slug emphasized) |
+| Container Detection | Trailing slash `/` | Link header `rel="type"` (planned) |
+| Metadata Updates | N3 Patch, SPARQL | JSON Merge Patch on linkset (planned) |
+
+**Current Status:**
+
+Currently, `--lws-mode` is primarily infrastructure. The PUT/POST semantics are **the same** as Solid/LDP (PUT can create or update).
+
+Future LWS-specific features (when implemented):
+- Link header-based container detection (alternative to trailing slash)
+- Linkset metadata endpoints (`/resource;linkset`)
+- JSON Merge Patch for metadata updates
+
+**Example:**
+```bash
+# Both work in LWS mode (same as default)
+curl -X PUT http://localhost:3000/alice/public/new.json \
+  -H "Content-Type: application/json" \
+  -d '{"test": true}'
+# 201 Created
+
+curl -X POST http://localhost:3000/alice/public/ \
+  -H "Content-Type: application/json" \
+  -H "Slug: another-resource" \
+  -d '{"test": true}'
+# 201 Created
+```
+
+**Status:** Early draft implementation. LWS spec is evolving - monitor ecosystem adoption before production use. Per Solid CG clarification, PUT creation is allowed in LWS.
+
 ### Profile Pages
 
 Pod profiles (`/alice/`) use HTML with embedded JSON-LD data islands and are rendered using:

@@ -47,6 +47,8 @@ program
   .option('--no-conneg', 'Disable content negotiation')
   .option('--notifications', 'Enable WebSocket notifications')
   .option('--no-notifications', 'Disable WebSocket notifications')
+  .option('--lws-mode', 'Enable LWS protocol mode (DRAFT - see issue #87)')
+  .option('--no-lws-mode', 'Use Solid/LDP protocol mode (default)')
   .option('--idp', 'Enable built-in Identity Provider')
   .option('--no-idp', 'Disable built-in Identity Provider')
   .option('--idp-issuer <url>', 'IdP issuer URL (defaults to server URL)')

@@ -28,6 +28,7 @@ export const defaults = {
   multiuser: true,
   conneg: false,
   notifications: false,
+  lwsMode: false,  // LWS protocol mode (draft)
 
   // Identity Provider
   idp: false,
@@ -89,6 +90,7 @@ const envMap = {
   JSS_MULTIUSER: 'multiuser',
   JSS_CONNEG: 'conneg',
   JSS_NOTIFICATIONS: 'notifications',
+  JSS_LWS_MODE: 'lwsMode',
   JSS_QUIET: 'quiet',
   JSS_CONFIG_PATH: 'configPath',
   JSS_IDP: 'idp',
@@ -259,6 +261,7 @@ export function printConfig(config) {
   console.log(`  Multi-user:    ${config.multiuser}`);
   console.log(`  Conneg:        ${config.conneg}`);
   console.log(`  Notifications: ${config.notifications}`);
+  console.log(`  LWS Mode:      ${config.lwsMode ? 'enabled (DRAFT)' : 'disabled'}`);
   console.log(`  IdP:           ${config.idp ? (config.idpIssuer || 'enabled') : 'disabled'}`);
   console.log(`  Subdomains:    ${config.subdomains ? (config.baseDomain || 'enabled') : 'disabled'}`);
   console.log(`  Mashlib:       ${config.mashlibCdn ? `CDN v${config.mashlibVersion}` : config.mashlib ? 'local' : 'disabled'}`);

@@ -44,6 +44,8 @@ export function createServer(options = {}) {
   const connegEnabled = options.conneg ?? false;
   // WebSocket notifications are OFF by default
   const notificationsEnabled = options.notifications ?? false;
+  // LWS protocol mode is OFF by default - use Solid/LDP semantics
+  const lwsMode = options.lwsMode ?? false;
   // Identity Provider is OFF by default
   const idpEnabled = options.idp ?? false;
   const idpIssuer = options.idpIssuer;
@@ -122,6 +124,7 @@ export function createServer(options = {}) {
   // Attach server config to requests
   fastify.decorateRequest('connegEnabled', null);
   fastify.decorateRequest('notificationsEnabled', null);
+  fastify.decorateRequest('lwsMode', null);
   fastify.decorateRequest('idpEnabled', null);
   fastify.decorateRequest('subdomainsEnabled', null);
   fastify.decorateRequest('baseDomain', null);
@@ -134,6 +137,7 @@ export function createServer(options = {}) {
   fastify.addHook('onRequest', async (request) => {
     request.connegEnabled = connegEnabled;
     request.notificationsEnabled = notificationsEnabled;
+    request.lwsMode = lwsMode;
     request.idpEnabled = idpEnabled;
     request.subdomainsEnabled = subdomainsEnabled;
     request.baseDomain = baseDomain;

@@ -0,0 +1,132 @@
+/**
+ * LWS Protocol Mode Tests (DRAFT)
+ *
+ * Tests for W3C Linked Web Storage protocol semantics.
+ * See issue #87 for full specification and implementation plan.
+ */
+
+import { describe, it, before, after } from 'node:test';
+import assert from 'node:assert';
+import {
+  startTestServer,
+  stopTestServer,
+  request,
+  createTestPod,
+  assertStatus
+} from './helpers.js';
+
+describe('LWS Protocol Mode (DRAFT)', () => {
+  let baseUrl;
+
+  before(async () => {
+    // Start server with LWS mode enabled
+    const result = await startTestServer({ lwsMode: true });
+    baseUrl = result.baseUrl;
+    await createTestPod('lwstest');
+  });
+
+  after(async () => {
+    await stopTestServer();
+  });
+
+  describe('PUT Semantics (Creation and Updates)', () => {
+    it('should allow PUT for resource creation in LWS mode', async () => {
+      // LWS allows PUT for creation (clarified by Eric on Solid CG call)
+      const res = await request('/lwstest/public/new-via-put.json', {
+        method: 'PUT',
+        headers: { 'Content-Type': 'application/json' },
+        body: JSON.stringify({ created: 'via PUT' }),
+        auth: 'lwstest'
+      });
+
+      assertStatus(res, 201);
+
+      // Verify created
+      const verify = await request('/lwstest/public/new-via-put.json');
+      const data = await verify.json();
+      assert.strictEqual(data.created, 'via PUT');
+    });
+
+    it('should allow PUT to update existing resource in LWS mode', async () => {
+      // First create via POST
+      const createRes = await request('/lwstest/public/', {
+        method: 'POST',
+        headers: {
+          'Content-Type': 'application/json',
+          'Slug': 'existing-resource'
+        },
+        body: JSON.stringify({ version: 1 }),
+        auth: 'lwstest'
+      });
+
+      assertStatus(createRes, 201);
+      const location = createRes.headers.get('Location');
+
+      // Now update via PUT (should work)
+      const updateRes = await request(location, {
+        method: 'PUT',
+        headers: { 'Content-Type': 'application/json' },
+        body: JSON.stringify({ version: 2 }),
+        auth: 'lwstest'
+      });
+
+      assertStatus(updateRes, 204);
+
+      // Verify updated
+      const verify = await request(location);
+      const data = await verify.json();
+      assert.strictEqual(data.version, 2);
+    });
+  });
+
+  describe('POST Creation (LWS Standard)', () => {
+    it('should create resource via POST with Slug header', async () => {
+      const res = await request('/lwstest/public/', {
+        method: 'POST',
+        headers: {
+          'Content-Type': 'application/json',
+          'Slug': 'lws-created'
+        },
+        body: JSON.stringify({ created: 'via POST' }),
+        auth: 'lwstest'
+      });
+
+      assertStatus(res, 201);
+      const location = res.headers.get('Location');
+      assert.ok(location, 'Should return Location header');
+      assert.ok(location.includes('lws-created'), 'Should use Slug in filename');
+    });
+
+    it('should create container via POST with Link header', async () => {
+      const res = await request('/lwstest/public/', {
+        method: 'POST',
+        headers: {
+          'Slug': 'lws-container',
+          'Link': '<http://www.w3.org/ns/ldp#BasicContainer>; rel="type"'
+        },
+        auth: 'lwstest'
+      });
+
+      assertStatus(res, 201);
+      const location = res.headers.get('Location');
+      assert.ok(location.endsWith('/'), 'Container should end with /');
+    });
+  });
+
+  describe('Documentation', () => {
+    it('should document LWS mode differences', () => {
+      // This test serves as documentation
+      const differences = {
+        PUT: 'Allowed for creation and updates (same as LDP)',
+        POST: 'Emphasized pattern with Slug for server-assigned URIs',
+        containerDetection: 'Link header (future: may remove slash semantics)',
+        metadataUpdates: 'Future: JSON Merge Patch on linkset resources',
+        etagRequirement: 'Mandatory (already implemented)'
+      };
+
+      // Note: Per Eric on Solid CG call, LWS allows PUT creation
+      // The main difference is POST+Slug is the emphasized pattern
+      assert.ok(differences.POST.includes('Slug'), 'POST with Slug emphasized');
+    });
+  });
+});