diff --git a/client/state/posts/reducer.js b/client/state/posts/reducer.js
index 35760038e099b..86686c657c5cb 100644
--- a/client/state/posts/reducer.js
+++ b/client/state/posts/reducer.js
@@ -23,6 +23,8 @@ import {
 	getSerializedPostsQueryWithoutPage
 } from './utils';
 import { DEFAULT_POST_QUERY } from './constants';
+import { itemsSchema } from './schema';
+import { isValidStateWithSchema } from 'state/utils';
 
 /**
  * Tracks all known post objects, indexed by post global ID.
@@ -36,8 +38,11 @@ export function items( state = {}, action ) {
 		case POSTS_RECEIVE:
 			return Object.assign( {}, state, keyBy( action.posts, 'global_ID' ) );
 		case SERIALIZE:
-			return {};
+			return state;
 		case DESERIALIZE:
+			if ( isValidStateWithSchema( state, itemsSchema ) ) {
+				return state;
+			}
 			return {};
 	}
 	return state;
diff --git a/client/state/posts/schema.js b/client/state/posts/schema.js
new file mode 100644
index 0000000000000..ab026525c3a09
--- /dev/null
+++ b/client/state/posts/schema.js
@@ -0,0 +1,53 @@
+export const itemsSchema = {
+	type: 'object',
+	patternProperties: {
+		//be careful to escape regexes properly
+		'^[0-9a-z]+$': {
+			type: 'object',
+			required: [ 'ID', 'site_ID', 'global_ID' ],
+			properties: {
+				ID: { type: 'integer' },
+				site_ID: { type: 'integer' },
+				global_ID: { type: 'string' },
+				author: { type: 'object' },
+				date: { type: 'string' },
+				modified: { type: 'string' },
+				title: { type: 'string' },
+				URL: { type: 'string' },
+				short_URL: { type: 'string' },
+				content: { type: 'string' },
+				excerpt: { type: 'string' },
+				slug: { type: 'string' },
+				guid: { type: 'string' },
+				status: { type: 'string' },
+				sticky: { type: 'boolean' },
+				password: { type: 'string' },
+				parent: { type: [ 'object', 'boolean' ] },
+				type: { type: 'string' },
+				discussion: { type: 'object' },
+				likes_enabled: { type: 'boolean' },
+				sharing_enabled: { type: 'boolean' },
+				like_count: { type: 'integer' },
+				i_like: { type: 'boolean' },
+				is_reblogged: { type: 'boolean' },
+				is_following: { type: 'boolean' },
+				featured_image: { type: 'string' },
+				post_thumbnail: { type: [ 'string', 'null' ] },
+				format: { type: 'string' },
+				geo: { type: 'boolean' },
+				menu_order: { type: 'integer' },
+				page_template: { type: 'string' },
+				publicize_URLS: { type: 'array' },
+				tags: { type: 'object' },
+				categories: { type: 'object' },
+				attachments: { type: 'object' },
+				attachment_count: { type: 'integer' },
+				metadata: { type: 'array' },
+				meta: { type: 'object' },
+				capabilities: { type: 'object' },
+				other_URLs: { type: 'object' }
+			}
+		}
+	},
+	additionalProperties: false
+};
diff --git a/client/state/posts/test/reducer.js b/client/state/posts/test/reducer.js
index a402ae628ff63..daee869a22b2c 100644
--- a/client/state/posts/test/reducer.js
+++ b/client/state/posts/test/reducer.js
@@ -3,6 +3,7 @@
  */
 import { expect } from 'chai';
 import deepFreeze from 'deep-freeze';
+import sinon from 'sinon';
 
 /**
  * Internal dependencies
@@ -77,20 +78,52 @@ describe( 'reducer', () => {
 			} );
 		} );
 
-		it( 'never persists state because this is not implemented', () => {
-			const original = deepFreeze( {
-				'3d097cb7c5473c169bba0eb8e3c6cb64': { ID: 841, site_ID: 2916284, global_ID: '3d097cb7c5473c169bba0eb8e3c6cb64', title: 'Hello World' }
+		describe( 'persistence', () => {
+			before( () => {
+				sinon.stub( console, 'warn' );
+			} );
+			after( () => {
+				console.warn.restore();
+			} );
+
+			it( 'persists state', () => {
+				const original = deepFreeze( {
+					'3d097cb7c5473c169bba0eb8e3c6cb64': {
+						ID: 841,
+						site_ID: 2916284,
+						global_ID: '3d097cb7c5473c169bba0eb8e3c6cb64',
+						title: 'Hello World'
+					}
+				} );
+				const state = items( original, { type: SERIALIZE } );
+				expect( state ).to.eql( original );
+			} );
+
+			it( 'loads valid persisted state', () => {
+				const original = deepFreeze( {
+					'3d097cb7c5473c169bba0eb8e3c6cb64': {
+						ID: 841,
+						site_ID: 2916284,
+						global_ID: '3d097cb7c5473c169bba0eb8e3c6cb64',
+						title: 'Hello World'
+					}
+				} );
+				const state = items( original, { type: DESERIALIZE } );
+				expect( state ).to.eql( original );
+			} );
+
+			it( 'loads default state when schema does not match', () => {
+				const original = deepFreeze( {
+					'3d097cb7c5473c169bba0eb8e3c6cb64': {
+						ID: 841,
+						site_ID: 'foo',
+						global_ID: '3d097cb7c5473c169bba0eb8e3c6cb64',
+						title: 'Hello World'
+					}
+				} );
+				const state = items( original, { type: DESERIALIZE } );
+				expect( state ).to.eql( {} );
 			} );
-			const state = items( original, { type: SERIALIZE } );
-			expect( state ).to.eql( {} );
-		} );
-
-		it( 'never loads persisted state because this is not implemented', () => {
-			const original = deepFreeze( {
-				'3d097cb7c5473c169bba0eb8e3c6cb64': { ID: 841, site_ID: 2916284, global_ID: '3d097cb7c5473c169bba0eb8e3c6cb64', title: 'Hello World' }
-			} );
-			const state = items( original, { type: DESERIALIZE } );
-			expect( state ).to.eql( {} );
 		} );
 	} );
 
@@ -215,7 +248,7 @@ describe( 'reducer', () => {
 			expect( state ).to.eql( {} );
 		} );
 
-		it( 'never loads persisted state because this is not implemented', () => {
+		it( 'never persists state because this is not implemented', () => {
 			const original = deepFreeze( {
 				'2916284:{"search":"hello"}': {
 					fetching: true
@@ -314,7 +347,7 @@ describe( 'reducer', () => {
 			} );
 		} );
 
-		it( 'never persists state because this is not implemented', () => {
+		it( 'never persists state', () => {
 			const original = deepFreeze( {
 				'2916284:{"search":"hello"}': 1
 			} );
@@ -322,7 +355,7 @@ describe( 'reducer', () => {
 			expect( state ).to.eql( {} );
 		} );
 
-		it( 'never loads persisted state because this is not implemented', () => {
+		it( 'never loads persisted state', () => {
 			const original = deepFreeze( {
 				'2916284:{"search":"hello"}': 1
 			} );
@@ -407,7 +440,7 @@ describe( 'reducer', () => {
 			} );
 		} );
 
-		it( 'never persists state because this is not implemented', () => {
+		it( 'never persists state', () => {
 			const state = siteRequests( deepFreeze( {
 				2916284: {
 					841: true
@@ -419,7 +452,7 @@ describe( 'reducer', () => {
 			expect( state ).to.eql( {} );
 		} );
 
-		it( 'never loads persisted state because this is not implemented', () => {
+		it( 'never loads persisted state', () => {
 			const state = siteRequests( deepFreeze( {
 				2916284: {
 					841: true