diff --git a/build/build-bundle.js b/build/build-bundle.js
index 077845fecf25..2dcd56d586c8 100644
--- a/build/build-bundle.js
+++ b/build/build-bundle.js
@@ -71,7 +71,14 @@ async function browserifyFile(entryPath, distPath) {
     .ignore('intl-pluralrules')
     .ignore('raven')
     .ignore('rimraf')
-    .ignore('pako/lib/zlib/inflate.js');
+    .ignore('pako/lib/zlib/inflate.js')
+    .ignore('file') // required by jsonlint-mod
+    .ignore('system'); // required by jsonlint-mod
+
+  // There is no way to add './doug-json-parse' to ignored packages via public API
+  // w/o browserify resolving the path into an absolute path
+  // @ts-ignore
+  bundle._ignore.push('./doug-json-parse');
 
   // Don't include the desktop protocol connection.
   bundle.ignore(require.resolve('../lighthouse-core/gather/connections/cri.js'));
diff --git a/lighthouse-cli/test/cli/__snapshots__/index-test.js.snap b/lighthouse-cli/test/cli/__snapshots__/index-test.js.snap
index e106723d1b59..50b1d1effa7b 100644
--- a/lighthouse-cli/test/cli/__snapshots__/index-test.js.snap
+++ b/lighthouse-cli/test/cli/__snapshots__/index-test.js.snap
@@ -420,6 +420,9 @@ Object {
     Object {
       "path": "seo/canonical",
     },
+    Object {
+      "path": "seo/json-ld",
+    },
     Object {
       "path": "seo/manual/structured-data",
     },
@@ -1109,6 +1112,11 @@ Object {
           "id": "canonical",
           "weight": 1,
         },
+        Object {
+          "group": "seo-content",
+          "id": "json-ld",
+          "weight": 1,
+        },
         Object {
           "group": "seo-mobile",
           "id": "font-size",
diff --git a/lighthouse-cli/test/fixtures/dobetterweb/dbw_tester.html b/lighthouse-cli/test/fixtures/dobetterweb/dbw_tester.html
index 403af919f2f8..41c67164821d 100644
--- a/lighthouse-cli/test/fixtures/dobetterweb/dbw_tester.html
+++ b/lighthouse-cli/test/fixtures/dobetterweb/dbw_tester.html
@@ -115,6 +115,15 @@
 <!-- Force FCP to be ~5s out, necessary to make sure our render-blocking audits still work -->
 <!-- even when other forces were responsible for delaying the render. -->
 <script src="./fcp-delayer.js?delay=5000"></script>
+
+<!-- FAIL(json-ld): unknown property in JSON-LD -->
+<script type="application/ld+json">
+{
+  "@context": "http://schema.org",
+  "@type": "Event",
+  "unknownProp": "Oh no"
+}
+</script>
 </head>
 <body>
 
diff --git a/lighthouse-cli/test/fixtures/seo/seo-failure-cases.html b/lighthouse-cli/test/fixtures/seo/seo-failure-cases.html
index f4640f0f1bd1..39ca3141f4ff 100644
--- a/lighthouse-cli/test/fixtures/seo/seo-failure-cases.html
+++ b/lighthouse-cli/test/fixtures/seo/seo-failure-cases.html
@@ -20,6 +20,14 @@
   <link rel="alternate" href="http://example.com/" hreflang=" x-default" />
   <!-- FAIL(canonical): multiple canonical URLs provided (another one is in the HTTP header) -->
   <link rel="canonical" href="https://example.com/other" />
+  <!-- FAIL(json-ld): invalid @type -->
+  <script type="application/ld+json">
+    {
+      "@context": "http://schema.org",
+      "@type": "CatConvention",
+      "name": "Cat Global"
+    }
+  </script>
 </head>
 <body>
   <h1>SEO</h1>
diff --git a/lighthouse-cli/test/fixtures/seo/seo-tester.html b/lighthouse-cli/test/fixtures/seo/seo-tester.html
index 1e381a96bc4e..08d4be964845 100644
--- a/lighthouse-cli/test/fixtures/seo/seo-tester.html
+++ b/lighthouse-cli/test/fixtures/seo/seo-tester.html
@@ -19,6 +19,14 @@
   <link rel="alternate" href="http://example.com/" hreflang="x-default" />
   <!-- PASS(canonical): valid canonical URL -->
   <link rel="canonical" href="http://localhost:10200/seo/" />
+  <!-- PASS(json-ld): valid JSON-LD -->
+  <script type="application/ld+json">
+    {
+      "@context": "http://schema.org",
+      "@type": "Event",
+      "name": "Cat Global"
+    }
+  </script>
 
   <style>
     .small {
diff --git a/lighthouse-cli/test/smokehouse/test-definitions/seo/expectations.js b/lighthouse-cli/test/smokehouse/test-definitions/seo/expectations.js
index 40921a259e00..0fbd492c8674 100644
--- a/lighthouse-cli/test/smokehouse/test-definitions/seo/expectations.js
+++ b/lighthouse-cli/test/smokehouse/test-definitions/seo/expectations.js
@@ -123,7 +123,7 @@ const expectations = [
                 source: {
                   url: /seo-tester\.html.+$/,
                   urlProvider: 'network',
-                  line: 23,
+                  line: 31,
                   column: 12,
                 },
                 selector: '.small',
@@ -133,7 +133,7 @@ const expectations = [
                 source: {
                   url: /seo-tester\.html.+$/,
                   urlProvider: 'network',
-                  line: 27,
+                  line: 35,
                   column: 55,
                 },
                 selector: '.small-2',
@@ -218,6 +218,9 @@ const expectations = [
           score: null,
           scoreDisplayMode: 'notApplicable',
         },
+        'json-ld': {
+          score: 1,
+        },
       },
     }},
   {
@@ -279,6 +282,21 @@ const expectations = [
           score: 0,
           explanation: 'Multiple conflicting URLs (https://example.com/other, https://example.com/)',
         },
+        'json-ld': {
+          score: 0,
+          details: {
+            items: [
+              {
+                'lineMessages': [
+                  {
+                    'lineNumber': 3,
+                    'message': 'Unrecognized schema.org type: http://schema.org/CatConvention',
+                  },
+                ],
+              },
+            ],
+          },
+        },
       },
     },
   },
diff --git a/lighthouse-core/audits/seo/json-ld.js b/lighthouse-core/audits/seo/json-ld.js
new file mode 100644
index 000000000000..e98f9a938c9b
--- /dev/null
+++ b/lighthouse-core/audits/seo/json-ld.js
@@ -0,0 +1,171 @@
+/**
+ * @license Copyright 2019 Google Inc. All Rights Reserved.
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.
+ */
+'use strict';
+
+const Audit = require('../audit.js');
+const validateJsonLD = require('../../lib/sd-validation/sd-validation.js');
+const i18n = require('../../lib/i18n/i18n.js');
+
+const UIStrings = {
+  /** Title of a Lighthouse audit that provides detail on whether JSON-LD structured data snippets are valid. This descriptive title is shown when no invalid JSON-LD snippets were found. */
+  title: 'JSON-LD structured data syntax is valid',
+  /** Title of a Lighthouse audit that provides detail on whether JSON-LD structured data snippets are valid. This descriptive title is shown when JSON-LD snippets with invalid content were found. */
+  failureTitle: 'JSON-LD structured data syntax is invalid',
+  /** Description of a Lighthouse audit that tells the user whether JSON-LD snippets on the page are invalid. This is displayed after a user expands the section to see more. No character length limits. */
+  /* eslint-disable-next-line max-len */
+  description: 'This audit currently validates a subset of JSON-LD rules used in search engines. See also the [Structured Data Testing Tool](https://search.google.com/structured-data/testing-tool/) to validate other types of structured data.',
+  /** Explanatory message stating how many JSON-LD structured data snippets are invalid */
+  displayValue: `{invalidSnippetCount, plural,
+    =1 {# invalid snippet}
+    other {# invalid snippets}
+    }`,
+};
+
+const str_ = i18n.createMessageInstanceIdFn(__filename, UIStrings);
+
+class StructuredDataAutomatic extends Audit {
+  /**
+   * @return {LH.Audit.Meta}
+   */
+  static get meta() {
+    return {
+      id: 'json-ld',
+      title: str_(UIStrings.title),
+      failureTitle: str_(UIStrings.failureTitle),
+      description: str_(UIStrings.description),
+      requiredArtifacts: ['ScriptElements'],
+    };
+  }
+
+  /**
+   * @param {LH.Artifacts} artifacts
+   * @return {Promise<LH.Audit.Product>}
+   */
+  static async audit(artifacts) {
+    const jsonLDElements = artifacts.ScriptElements.filter(
+      script => script.type === 'application/ld+json' && !!script.content);
+
+    if (jsonLDElements.length === 0) {
+      return {
+        notApplicable: true,
+        score: 1,
+      };
+    }
+
+    const snippets = await Promise.all(jsonLDElements.map(async (element) => {
+      // We don't want to show empty lines around the snippet
+      // We can do this cast, because we know element.content to not be null
+      const content = /** @type string */ (element.content).trim();
+
+      return {
+        devtoolsNodePath: element.devtoolsNodePath,
+        content,
+        errors: await validateJsonLD(content),
+      };
+    }));
+    // Show invalid snippets at the top
+    snippets.sort((a, b) => {
+      return b.errors.length - a.errors.length;
+    });
+
+    const renderedSnippets = snippets.map(renderValidatedSnippet);
+    const details = Audit.makeListDetails(renderedSnippets);
+
+    const invalidSnippets = snippets.filter(vs => vs.errors.length > 0);
+    const displayValue = str_(UIStrings.displayValue, {
+      invalidSnippetCount: invalidSnippets.length,
+    });
+
+    return {
+      score: invalidSnippets.length === 0 ? 1 : 0,
+      details,
+      displayValue,
+    };
+  }
+}
+
+/**
+ * @param {{content: string, devtoolsNodePath: string, errors: LH.StructuredData.ValidationError[]}} validatedSnippet
+ */
+function renderValidatedSnippet(validatedSnippet) {
+  const {content, devtoolsNodePath, errors} = validatedSnippet;
+
+  /** @type {LH.StructuredData.JsonLDDocument} */
+  let parsedContent = {};
+  let topLevelType = '';
+  let topLevelName = '';
+  try {
+    parsedContent = JSON.parse(content);
+  } catch (err) {}
+  if (parsedContent['@type']) {
+    topLevelType = parsedContent['@type'];
+  }
+  if (typeof parsedContent.name === 'string') {
+    topLevelName = parsedContent.name.toString();
+  }
+
+  let title = '';
+  if (topLevelName && topLevelType) {
+    title = `${topLevelType}: ${topLevelName}`;
+  } else if (topLevelType) {
+    title = `@type ${topLevelType}`;
+  } else {
+    title = 'Invalid JSON-LD element';
+  }
+  // No 18n here, because it's tricky to do because of the if statement above. The
+  // entity type and error messages are in English anyway.
+  title += ` (${errors.length} Error${errors.length !== 1 ? 's' : ''})`;
+
+  /** @type LH.Audit.Details.NodeValue */
+  const node = {
+    type: 'node',
+    path: devtoolsNodePath,
+    snippet: `<script type="application/ld+json">`,
+  };
+
+  const {lineMessages, generalMessages} = getErrorMessages(errors);
+
+  return Audit.makeSnippetDetails({
+    content: parsedContent ? JSON.stringify(parsedContent, null, 2) : content,
+    title,
+    lineMessages,
+    generalMessages,
+    node,
+  });
+}
+
+/**
+ * @param {Array<LH.StructuredData.ValidationError>} errors
+ */
+function getErrorMessages(errors) {
+  /** @type {LH.Audit.Details.SnippetValue['lineMessages']} */
+  const lineMessages = [];
+  /** @type {LH.Audit.Details.SnippetValue['generalMessages']} */
+  const generalMessages = [];
+  errors.forEach(({
+    message, lineNumber, validTypes, validator,
+  }) => {
+    if (validTypes && validator === 'schema-org') {
+      const typeStrings = validTypes.map(type => {
+        return `[${type.name}](${type.uri})`;
+      });
+      message = `Invalid ${typeStrings.join('/')}: ${message}`;
+    }
+
+    if (lineNumber) {
+      lineMessages.push({lineNumber, message});
+    } else {
+      generalMessages.push({
+        message,
+      });
+    }
+  });
+
+  return {lineMessages, generalMessages};
+}
+
+module.exports = StructuredDataAutomatic;
+module.exports.UIStrings = UIStrings;
diff --git a/lighthouse-core/config/default-config.js b/lighthouse-core/config/default-config.js
index b1f282c1c36e..f14c440e2cef 100644
--- a/lighthouse-core/config/default-config.js
+++ b/lighthouse-core/config/default-config.js
@@ -312,6 +312,7 @@ const defaultConfig = {
     'seo/hreflang',
     'seo/plugins',
     'seo/canonical',
+    'seo/json-ld',
     'seo/manual/structured-data',
   ],
 
@@ -539,6 +540,7 @@ const defaultConfig = {
         {id: 'image-alt', weight: 1, group: 'seo-content'},
         {id: 'hreflang', weight: 1, group: 'seo-content'},
         {id: 'canonical', weight: 1, group: 'seo-content'},
+        {id: 'json-ld', weight: 1, group: 'seo-content'},
         {id: 'font-size', weight: 1, group: 'seo-mobile'},
         {id: 'plugins', weight: 1, group: 'seo-content'},
         {id: 'tap-targets', weight: 1, group: 'seo-mobile'},
diff --git a/lighthouse-core/lib/i18n/locales/en-US.json b/lighthouse-core/lib/i18n/locales/en-US.json
index 8e64a615ca7f..d4edffd4dcea 100644
--- a/lighthouse-core/lib/i18n/locales/en-US.json
+++ b/lighthouse-core/lib/i18n/locales/en-US.json
@@ -1040,6 +1040,18 @@
   "lighthouse-core/audits/seo/is-crawlable.js | title": {
     "message": "Page isn’t blocked from indexing"
   },
+  "lighthouse-core/audits/seo/json-ld.js | description": {
+    "message": "This audit currently validates a subset of JSON-LD rules used in search engines. See also the [Structured Data Testing Tool](https://search.google.com/structured-data/testing-tool/) to validate other types of structured data."
+  },
+  "lighthouse-core/audits/seo/json-ld.js | displayValue": {
+    "message": "{invalidSnippetCount, plural,\n    =1 {# invalid snippet}\n    other {# invalid snippets}\n    }"
+  },
+  "lighthouse-core/audits/seo/json-ld.js | failureTitle": {
+    "message": "JSON-LD structured data syntax is invalid"
+  },
+  "lighthouse-core/audits/seo/json-ld.js | title": {
+    "message": "JSON-LD structured data syntax is valid"
+  },
   "lighthouse-core/audits/seo/link-text.js | description": {
     "message": "Descriptive link text helps search engines understand your content. [Learn more](https://web.dev/link-text)."
   },
diff --git a/lighthouse-core/lib/i18n/locales/en-XL.json b/lighthouse-core/lib/i18n/locales/en-XL.json
index 3e07156bdc72..d9b53f75c2fb 100644
--- a/lighthouse-core/lib/i18n/locales/en-XL.json
+++ b/lighthouse-core/lib/i18n/locales/en-XL.json
@@ -1040,6 +1040,18 @@
   "lighthouse-core/audits/seo/is-crawlable.js | title": {
     "message": "P̂áĝé îśn̂’t́ b̂ĺôćk̂éd̂ f́r̂óm̂ ín̂d́êx́îńĝ"
   },
+  "lighthouse-core/audits/seo/json-ld.js | description": {
+    "message": "T̂h́îś âúd̂ít̂ ćûŕr̂én̂t́l̂ý v̂ál̂íd̂át̂éŝ á ŝúb̂śêt́ ôf́ ĴŚÔŃ-L̂D́ r̂úl̂éŝ úŝéd̂ ín̂ śêár̂ćĥ én̂ǵîńêś. Ŝéê ál̂śô t́ĥé [Ŝt́r̂úĉt́ûŕêd́ D̂át̂á T̂éŝt́îńĝ T́ôól̂](https://search.google.com/structured-data/testing-tool/) t́ô v́âĺîd́ât́ê ót̂h́êŕ t̂ýp̂éŝ óf̂ śt̂ŕûćt̂úr̂éd̂ d́ât́â."
+  },
+  "lighthouse-core/audits/seo/json-ld.js | displayValue": {
+    "message": "{invalidSnippetCount, plural,\n    =1 {# îńv̂ál̂íd̂ śn̂íp̂ṕêt́}\n    other {# îńv̂ál̂íd̂ śn̂íp̂ṕêt́ŝ}\n    }"
+  },
+  "lighthouse-core/audits/seo/json-ld.js | failureTitle": {
+    "message": "ĴŚÔŃ-L̂D́ ŝt́r̂úĉt́ûŕêd́ d̂át̂á ŝýn̂t́âx́ îś îńv̂ál̂íd̂"
+  },
+  "lighthouse-core/audits/seo/json-ld.js | title": {
+    "message": "ĴŚÔŃ-L̂D́ ŝt́r̂úĉt́ûŕêd́ d̂át̂á ŝýn̂t́âx́ îś v̂ál̂íd̂"
+  },
   "lighthouse-core/audits/seo/link-text.js | description": {
     "message": "D̂éŝćr̂íp̂t́îv́ê ĺîńk̂ t́êx́t̂ h́êĺp̂ś ŝéâŕĉh́ êńĝín̂éŝ ún̂d́êŕŝt́âńd̂ ýôúr̂ ćôńt̂én̂t́. [L̂éâŕn̂ ḿôŕê](https://web.dev/link-text)."
   },
diff --git a/lighthouse-core/lib/sd-validation/schema-validator.js b/lighthouse-core/lib/sd-validation/schema-validator.js
index 6964d7ff0bf2..8cdf2bfeb1b4 100644
--- a/lighthouse-core/lib/sd-validation/schema-validator.js
+++ b/lighthouse-core/lib/sd-validation/schema-validator.js
@@ -96,11 +96,18 @@ function validateObjectKeys(typeOrTypes, keys) {
     // remove Schema.org input/output constraints http://schema.org/docs/actions.html#part-4
     .map(key => key.replace(/-(input|output)$/, ''))
     .filter(key => !allKnownProps.has(key))
-    .map(key => ({
-      message: `Unexpected property "${key}"`,
-      key,
-      validTypes: types,
-    }));
+    .map(key => {
+      return ({
+        message: `Unexpected property "${key}"`,
+        key,
+        validTypes: types.map(typeUri => {
+          const typeNameMatch = typeUri.match(/[\w]+$/);
+          const name = typeNameMatch ? typeNameMatch[0] : typeUri;
+          const uri = typeUri.replace('http://', 'https://');
+          return {name, uri};
+        }),
+      });
+    });
 }
 
 /**
diff --git a/lighthouse-core/report/html/report-styles.css b/lighthouse-core/report/html/report-styles.css
index 6e1c220eede1..e927584c5771 100644
--- a/lighthouse-core/report/html/report-styles.css
+++ b/lighthouse-core/report/html/report-styles.css
@@ -55,6 +55,7 @@
   --color-orange: #FFA400;
   --color-red-700: #EB0F00;
   --color-red: #FF4E42;
+  --color-red-100: #FFEDEC;
   --color-teal-600: #00897B;
   --color-white: #FFFFFF;
 
@@ -79,6 +80,7 @@
   --category-padding: 40px;
   --chevron-line-stroke: var(--color-gray-600);
   --chevron-size: 12px;
+  --code-snippet-color: #0938C2;
   --default-padding: 12px;
   --env-item-background-color: var(--color-gray-100);
   --env-item-font-size: 28px;
@@ -128,7 +130,8 @@
   --scorescale-width: 18px;
   --section-padding-vertical: 12px;
   --snippet-background-color: var(--color-gray-50);
-  --snippet-color: #0938C2;
+  --snippet-highlight-background-color: var(--color-red-700);
+  --snippet-annotation-background-color: var(--color-red-100);
   --sparkline-height: 5px;
   --stackpack-padding-horizontal: 10px;
   --sticky-header-background-color: var(--report-background-color);
@@ -180,6 +183,7 @@
     --color-informative: var(--color-blue-200);
 
     /* Component variables */
+    --code-snippet-color: var(--color-cyan-500);
     --env-item-background-color: var(--color-gray);
     --plugin-badge-background-color: var(--color-gray-800);
     --report-background-color: var(--color-gray-900);
@@ -187,7 +191,7 @@
     --report-text-color-secondary: var(--color-gray-400);
     --report-text-color: var(--color-gray-100);
     --topbar-background-color: var(--color-gray);
-    --snippet-color: var(--color-cyan-500);
+    --snippet-background-color: var(--color-gray-900);
 
     /* SVGs */
     --plugin-icon-url: var(--plugin-icon-url-dark);
@@ -414,7 +418,7 @@
 /* Node */
 .lh-node__snippet {
   font-family: var(--report-font-family-monospace);
-  color: var(--snippet-color);
+  color: var(--code-snippet-color);
   font-size: 14px;
   line-height: 20px;
 }
@@ -500,7 +504,7 @@
 }
 
 .lh-audit__title-and-text code {
-  color: var(--snippet-color);
+  color: var(--code-snippet-color);
   font-size: 15px;
 }
 
diff --git a/lighthouse-core/report/html/templates.html b/lighthouse-core/report/html/templates.html
index 6af232a56b5f..06ec896d183a 100644
--- a/lighthouse-core/report/html/templates.html
+++ b/lighthouse-core/report/html/templates.html
@@ -819,17 +819,11 @@
 <template id="tmpl-lh-snippet">
     <div class="lh-snippet">
       <style>
-          :root {
-            --snippet-highlight-light: #fbf1f2;
-            --snippet-highlight-dark: #ffd6d8;
-          }
-
          .lh-snippet__header {
           position: relative;
           overflow: hidden;
           padding: 10px;
           border-bottom: none;
-          color: var(--snippet-color);
           background-color: var(--snippet-background-color);
           border: 1px solid var(--report-border-color-secondary);
         }
@@ -871,7 +865,7 @@
         }
 
         .lh-snippet__line {
-          background: white;
+          background: var(--snippet-background-color, white);
           white-space: pre;
           display: flex;
         }
@@ -882,10 +876,10 @@
           padding-bottom: 4px;
         }
         .lh-snippet__line--content-highlighted {
-          background: var(--snippet-highlight-dark);
+          background: var(--snippet-highlight-background-color);
         }
         .lh-snippet__line--message {
-          background: var(--snippet-highlight-light);
+          background: var(--snippet-annotation-background-color);
         }
         .lh-snippet__line--message .lh-snippet__line-number {
           padding-top: 10px;
diff --git a/lighthouse-core/test/audits/seo/json-ld-test.js b/lighthouse-core/test/audits/seo/json-ld-test.js
new file mode 100644
index 000000000000..6ac00b19fc42
--- /dev/null
+++ b/lighthouse-core/test/audits/seo/json-ld-test.js
@@ -0,0 +1,150 @@
+/**
+ * @license Copyright 2019 Google Inc. All Rights Reserved.
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.
+ */
+'use strict';
+
+const AutomaticStructuredDataAudit = require('../../../audits/seo/json-ld.js');
+
+/* eslint-env jest */
+
+describe('SEO: structured data audit', () => {
+  it('reports both valid and invalid json-ld snippets', async () => {
+    const artifacts = {
+      ScriptElements: [
+        // Empty snippet is not included in the audit
+        {
+          type: 'application/ld+json',
+          content: null,
+          devtoolsNodePath: '3,HTML,0,HEAD,29,SCRIPT',
+        },
+        {
+          'type': 'application/ld+json',
+          'content': JSON.stringify({
+            '@context': 'http://schema.org',
+            '@type': 'Event',
+            'name': 'Cat Convention',
+          }),
+          'devtoolsNodePath': '3,HTML,0,HEAD,30,SCRIPT',
+        },
+        {
+          'type': 'application/ld+json',
+          'content': `
+            ${JSON.stringify({
+    '@context': 'http://schema.org',
+    '@type': 'Event',
+    'title': 'Cat Convention',
+  })} `,
+          'devtoolsNodePath': '3,HTML,0,HEAD,31,SCRIPT',
+        },
+      ],
+    };
+
+    const auditResult = await AutomaticStructuredDataAudit.audit(artifacts);
+
+    expect(auditResult).toMatchObject({
+      score: 0,
+      details: {
+        type: 'list',
+        // Failed snippet comes first
+        items: [{
+          'type': 'snippet',
+          'title': '@type Event (1 Error)',
+          'lineMessages': [
+            {
+              'lineNumber': 4,
+              'message': 'Invalid [Event](https://schema.org/Event): Unexpected property "title"',
+            },
+          ],
+          'generalMessages': [],
+          'node': {
+            'type': 'node',
+            'path': '3,HTML,0,HEAD,31,SCRIPT',
+            'snippet': '<script type="application/ld+json">',
+          },
+        },
+        // Valid snipppet comes last
+        {
+          'type': 'snippet',
+          'title': 'Event: Cat Convention (0 Errors)',
+          'lineMessages': [],
+          'generalMessages': [],
+          'node': {
+            'type': 'node',
+            'path': '3,HTML,0,HEAD,30,SCRIPT',
+            'snippet': '<script type="application/ld+json">',
+          },
+        }],
+      },
+    });
+
+    expect(auditResult.displayValue).toBeDisplayString('1 invalid snippet');
+  });
+
+  it('is not applicable if there are no json ld snippets with content on the page', async () => {
+    const artifacts = {
+      ScriptElements: [
+        // Empty snippet is not included in the audit
+        {
+          type: 'application/ld+json',
+          content: null,
+        },
+        {
+          'type': 'application/javascript',
+          'content': 'some content',
+        },
+      ],
+    };
+
+    const auditResult = await AutomaticStructuredDataAudit.audit(artifacts);
+    expect(auditResult.notApplicable).toBe(true);
+    expect(auditResult.score).toBe(1);
+  });
+
+  it('passes if all json ld snippets are valid', async () => {
+    const artifacts = {
+      ScriptElements: [
+        {
+          'type': 'application/ld+json',
+          'content': JSON.stringify({
+            '@context': 'http://schema.org',
+            '@type': 'Event',
+            'name': 'Cat Convention',
+          }),
+          'devtoolsNodePath': '3,HTML,0,HEAD,30,SCRIPT',
+        },
+      ],
+    };
+
+    const auditResult = await AutomaticStructuredDataAudit.audit(artifacts);
+    expect(auditResult.score).toBe(1);
+    expect(auditResult.displayValue).toBeDisplayString('0 invalid snippets');
+  });
+
+  // eslint-disable-next-line max-len
+  it('does not use [object object] in the title if the top-level name property is an object', async () => {
+    const artifacts = {
+      ScriptElements: [
+        {
+          'type': 'application/ld+json',
+          'content': JSON.stringify({
+            '@context': {
+              'schema': 'http://schema.org/',
+              'name': {'@id': 'schema:name', '@container': '@language'},
+            },
+            'name': {
+              'en': 'sth',
+              'fr': 'qqc',
+            },
+            '@type': 'schema:Event',
+          }),
+          'devtoolsNodePath': '3,HTML,0,HEAD,30,SCRIPT',
+        },
+      ],
+    };
+
+    const auditResult = await AutomaticStructuredDataAudit.audit(artifacts);
+    expect(auditResult.details.items[0].title).toBe('@type schema:Event (0 Errors)');
+  });
+});
diff --git a/lighthouse-core/test/lib/sd-validation-test.js b/lighthouse-core/test/lib/sd-validation-test.js
index ce7c1e5ca1e1..63c38c8b400f 100644
--- a/lighthouse-core/test/lib/sd-validation-test.js
+++ b/lighthouse-core/test/lib/sd-validation-test.js
@@ -171,7 +171,10 @@ describe('schema.org validation', () => {
     }`);
 
     assert.equal(errors.length, 1);
-    assert.equal(errors[0].validTypes[0], 'http://schema.org/Article');
+    assert.deepEqual(errors[0].validTypes, [{
+      name: 'Article',
+      uri: 'https://schema.org/Article',
+    }]);
     assert.equal(errors[0].message, 'Unexpected property "controversial"');
     assert.strictEqual(errors[0].lineNumber, 11);
   });
diff --git a/lighthouse-core/test/report/html/renderer/category-renderer-test.js b/lighthouse-core/test/report/html/renderer/category-renderer-test.js
index 26900fbdadbb..88420ae9a701 100644
--- a/lighthouse-core/test/report/html/renderer/category-renderer-test.js
+++ b/lighthouse-core/test/report/html/renderer/category-renderer-test.js
@@ -16,6 +16,8 @@ const DOM = require('../../../../report/html/renderer/dom.js');
 const DetailsRenderer = require('../../../../report/html/renderer/details-renderer.js');
 const CriticalRequestChainRenderer = require(
     '../../../../report/html/renderer/crc-details-renderer.js');
+const SnippetRenderer = require(
+    '../../../../report/html/renderer/snippet-renderer.js');
 const CategoryRenderer = require('../../../../report/html/renderer/category-renderer.js');
 const sampleResultsOrig = require('../../../results/sample_v2.json');
 
@@ -30,6 +32,7 @@ describe('CategoryRenderer', () => {
     global.Util = Util;
     global.Util.i18n = new I18n('en', {...Util.UIStrings});
     global.CriticalRequestChainRenderer = CriticalRequestChainRenderer;
+    global.SnippetRenderer = SnippetRenderer;
 
     const {document} = new jsdom.JSDOM(TEMPLATE_FILE).window;
     const dom = new DOM(document);
@@ -43,6 +46,7 @@ describe('CategoryRenderer', () => {
     global.Util.i18n = undefined;
     global.Util = undefined;
     global.CriticalRequestChainRenderer = undefined;
+    global.SnippetRenderer = undefined;
   });
 
   it('renders an audit', () => {
diff --git a/lighthouse-core/test/report/html/renderer/report-renderer-test.js b/lighthouse-core/test/report/html/renderer/report-renderer-test.js
index 0c00f0138289..274ffa3bb710 100644
--- a/lighthouse-core/test/report/html/renderer/report-renderer-test.js
+++ b/lighthouse-core/test/report/html/renderer/report-renderer-test.js
@@ -19,6 +19,7 @@ const ReportUIFeatures = require('../../../../report/html/renderer/report-ui-fea
 const CategoryRenderer = require('../../../../report/html/renderer/category-renderer.js');
 const CriticalRequestChainRenderer = require(
     '../../../../report/html/renderer/crc-details-renderer.js');
+const SnippetRenderer = require('../../../../report/html/renderer/snippet-renderer.js');
 const ReportRenderer = require('../../../../report/html/renderer/report-renderer.js');
 const sampleResultsOrig = require('../../../results/sample_v2.json');
 
@@ -37,6 +38,7 @@ describe('ReportRenderer', () => {
     global.CriticalRequestChainRenderer = CriticalRequestChainRenderer;
     global.DetailsRenderer = DetailsRenderer;
     global.CategoryRenderer = CategoryRenderer;
+    global.SnippetRenderer = SnippetRenderer;
 
     // lazy loaded because they depend on CategoryRenderer to be available globally
     global.PerformanceCategoryRenderer =
@@ -72,6 +74,7 @@ describe('ReportRenderer', () => {
     global.CategoryRenderer = undefined;
     global.PerformanceCategoryRenderer = undefined;
     global.PwaCategoryRenderer = undefined;
+    global.SnippetRenderer = undefined;
   });
 
   describe('renderReport', () => {
diff --git a/lighthouse-core/test/report/html/renderer/report-ui-features-test.js b/lighthouse-core/test/report/html/renderer/report-ui-features-test.js
index be4204285f5c..f091cdc6ee73 100644
--- a/lighthouse-core/test/report/html/renderer/report-ui-features-test.js
+++ b/lighthouse-core/test/report/html/renderer/report-ui-features-test.js
@@ -18,6 +18,8 @@ const ReportUIFeatures = require('../../../../report/html/renderer/report-ui-fea
 const CategoryRenderer = require('../../../../report/html/renderer/category-renderer.js');
 const CriticalRequestChainRenderer = require(
     '../../../../report/html/renderer/crc-details-renderer.js');
+const SnippetRenderer = require(
+    '../../../../report/html/renderer/snippet-renderer.js');
 const ReportRenderer = require('../../../../report/html/renderer/report-renderer.js');
 const sampleResultsOrig = require('../../../results/sample_v2.json');
 
@@ -51,6 +53,7 @@ describe('ReportUIFeatures', () => {
     global.CriticalRequestChainRenderer = CriticalRequestChainRenderer;
     global.DetailsRenderer = DetailsRenderer;
     global.CategoryRenderer = CategoryRenderer;
+    global.SnippetRenderer = SnippetRenderer;
 
     // lazy loaded because they depend on CategoryRenderer to be available globally
     global.PerformanceCategoryRenderer =
@@ -106,6 +109,7 @@ describe('ReportUIFeatures', () => {
     global.window = undefined;
     global.HTMLElement = undefined;
     global.HTMLInputElement = undefined;
+    global.SnippetRenderer = undefined;
   });
 
   describe('initFeatures', () => {
diff --git a/lighthouse-core/test/results/artifacts/artifacts.json b/lighthouse-core/test/results/artifacts/artifacts.json
index 13d0134538de..bbc17ff58736 100644
--- a/lighthouse-core/test/results/artifacts/artifacts.json
+++ b/lighthouse-core/test/results/artifacts/artifacts.json
@@ -292,6 +292,16 @@
       "content": null,
       "requestId": null
     },
+    {
+      "type": "application/ld+json",
+      "src": null,
+      "async": true,
+      "defer": false,
+      "source": "head",
+      "devtoolsNodePath": "3,HTML,0,HEAD,41,SCRIPT",
+      "content": "\n{\n  \"@context\": \"http://schema.org\",\n  \"@type\": \"Event\",\n  \"unknownProp\": \"Oh no\"\n}\n",
+      "requestId": "257C485E35F1F25EA4C4EEECA795B85B"
+    },
     {
       "type": null,
       "src": null,
diff --git a/lighthouse-core/test/results/sample_v2.json b/lighthouse-core/test/results/sample_v2.json
index 37c8f7eaaa8d..efff480f0462 100644
--- a/lighthouse-core/test/results/sample_v2.json
+++ b/lighthouse-core/test/results/sample_v2.json
@@ -3551,6 +3551,58 @@
       "score": null,
       "scoreDisplayMode": "notApplicable"
     },
+    "json-ld": {
+      "id": "json-ld",
+      "title": "JSON-LD structured data syntax is invalid",
+      "description": "This audit currently validates a subset of JSON-LD rules used in search engines. See also the [Structured Data Testing Tool](https://search.google.com/structured-data/testing-tool/) to validate other types of structured data.",
+      "score": 0,
+      "scoreDisplayMode": "binary",
+      "displayValue": "1 invalid snippet",
+      "details": {
+        "type": "list",
+        "items": [
+          {
+            "type": "snippet",
+            "lines": [
+              {
+                "content": "{",
+                "lineNumber": 1
+              },
+              {
+                "content": "  \"@context\": \"http://schema.org\",",
+                "lineNumber": 2
+              },
+              {
+                "content": "  \"@type\": \"Event\",",
+                "lineNumber": 3
+              },
+              {
+                "content": "  \"unknownProp\": \"Oh no\"",
+                "lineNumber": 4
+              },
+              {
+                "content": "}",
+                "lineNumber": 5
+              }
+            ],
+            "title": "@type Event (1 Error)",
+            "lineMessages": [
+              {
+                "lineNumber": 4,
+                "message": "Invalid [Event](https://schema.org/Event): Unexpected property \"unknownProp\""
+              }
+            ],
+            "generalMessages": [],
+            "lineCount": 5,
+            "node": {
+              "type": "node",
+              "path": "3,HTML,0,HEAD,41,SCRIPT",
+              "snippet": "<script type=\"application/ld+json\">"
+            }
+          }
+        ]
+      }
+    },
     "structured-data": {
       "id": "structured-data",
       "title": "Structured data is valid",
@@ -4297,6 +4349,11 @@
           "weight": 0,
           "group": "seo-content"
         },
+        {
+          "id": "json-ld",
+          "weight": 1,
+          "group": "seo-content"
+        },
         {
           "id": "font-size",
           "weight": 1,
@@ -4318,7 +4375,7 @@
         }
       ],
       "id": "seo",
-      "score": 0.73
+      "score": 0.67
     },
     "pwa": {
       "title": "Progressive Web App",
@@ -5564,6 +5621,12 @@
         "duration": 100,
         "entryType": "measure"
       },
+      {
+        "startTime": 0,
+        "name": "lh:audit:json-ld",
+        "duration": 100,
+        "entryType": "measure"
+      },
       {
         "startTime": 0,
         "name": "lh:audit:structured-data",
@@ -6837,6 +6900,20 @@
       "lighthouse-core/audits/seo/canonical.js | description": [
         "audits.canonical.description"
       ],
+      "lighthouse-core/audits/seo/json-ld.js | failureTitle": [
+        "audits[json-ld].title"
+      ],
+      "lighthouse-core/audits/seo/json-ld.js | description": [
+        "audits[json-ld].description"
+      ],
+      "lighthouse-core/audits/seo/json-ld.js | displayValue": [
+        {
+          "values": {
+            "invalidSnippetCount": 1
+          },
+          "path": "audits[json-ld].displayValue"
+        }
+      ],
       "lighthouse-core/audits/seo/manual/structured-data.js | title": [
         "audits[structured-data].title"
       ],
diff --git a/package.json b/package.json
index 38e1999d5b4e..3a6b69ce14b5 100644
--- a/package.json
+++ b/package.json
@@ -190,7 +190,7 @@
     },
     {
       "path": "./dist/lightrider/lighthouse-lr-bundle.js",
-      "maxSize": "1.50 MB"
+      "maxSize": "1.60 MB"
     },
     {
       "path": "./dist/viewer/src/viewer.js",
@@ -198,7 +198,7 @@
     },
     {
       "path": "./dist/lighthouse-dt-bundle.js",
-      "maxSize": "460 kB"
+      "maxSize": "550 kB"
     },
     {
       "path": "./dist/lightrider/report-generator-bundle.js",
diff --git a/proto/sample_v2_round_trip.json b/proto/sample_v2_round_trip.json
index 2a480aebe3a9..277eeb56818c 100644
--- a/proto/sample_v2_round_trip.json
+++ b/proto/sample_v2_round_trip.json
@@ -1290,6 +1290,58 @@
             "scoreDisplayMode": "binary",
             "title": "Detected JavaScript libraries"
         },
+        "json-ld": {
+            "description": "This audit currently validates a subset of JSON-LD rules used in search engines. See also the [Structured Data Testing Tool](https://search.google.com/structured-data/testing-tool/) to validate other types of structured data.",
+            "details": {
+                "items": [
+                    {
+                        "generalMessages": [],
+                        "lineCount": 5.0,
+                        "lineMessages": [
+                            {
+                                "lineNumber": 4.0,
+                                "message": "Invalid [Event](https://schema.org/Event): Unexpected property \"unknownProp\""
+                            }
+                        ],
+                        "lines": [
+                            {
+                                "content": "{",
+                                "lineNumber": 1.0
+                            },
+                            {
+                                "content": "  \"@context\": \"http://schema.org\",",
+                                "lineNumber": 2.0
+                            },
+                            {
+                                "content": "  \"@type\": \"Event\",",
+                                "lineNumber": 3.0
+                            },
+                            {
+                                "content": "  \"unknownProp\": \"Oh no\"",
+                                "lineNumber": 4.0
+                            },
+                            {
+                                "content": "}",
+                                "lineNumber": 5.0
+                            }
+                        ],
+                        "node": {
+                            "path": "3,HTML,0,HEAD,41,SCRIPT",
+                            "snippet": "<script type=\"application/ld+json\">",
+                            "type": "node"
+                        },
+                        "title": "@type Event (1 Error)",
+                        "type": "snippet"
+                    }
+                ],
+                "type": "list"
+            },
+            "displayValue": "1 invalid snippet",
+            "id": "json-ld",
+            "score": 0.0,
+            "scoreDisplayMode": "binary",
+            "title": "JSON-LD structured data syntax is invalid"
+        },
         "label": {
             "description": "Labels ensure that form controls are announced properly by assistive technologies, like screen readers. [Learn more](https://web.dev/label/).",
             "details": {
@@ -4213,6 +4265,11 @@
                     "id": "canonical",
                     "weight": 0.0
                 },
+                {
+                    "group": "seo-content",
+                    "id": "json-ld",
+                    "weight": 1.0
+                },
                 {
                     "group": "seo-mobile",
                     "id": "font-size",
@@ -4236,7 +4293,7 @@
             "description": "These checks ensure that your page is optimized for search engine results ranking. There are additional factors Lighthouse does not check that may affect your search ranking. [Learn more](https://support.google.com/webmasters/answer/35769).",
             "id": "seo",
             "manualDescription": "Run these additional validators on your site to check additional SEO best practices.",
-            "score": 0.73,
+            "score": 0.67,
             "title": "SEO"
         }
     },
@@ -5478,6 +5535,12 @@
                 "name": "lh:audit:canonical",
                 "startTime": 0.0
             },
+            {
+                "duration": 100.0,
+                "entryType": "measure",
+                "name": "lh:audit:json-ld",
+                "startTime": 0.0
+            },
             {
                 "duration": 100.0,
                 "entryType": "measure",
diff --git a/types/structured-data.d.ts b/types/structured-data.d.ts
index 8b5f02b66828..65f421bd15af 100644
--- a/types/structured-data.d.ts
+++ b/types/structured-data.d.ts
@@ -17,16 +17,28 @@ declare global {
         validator: ValidatorType;
         lineNumber?: number | null;
         /** Schema.org type URIs of the invalid entity (undefined if type is invalid) */
-        validTypes?: Array<string>;
+        validTypes?: Array<{
+          uri: string;
+          name: string;
+        }>;
+      }
+
+      export type JsonLDPrimitive = string | number | boolean | undefined
+      export type JsonLDPropertyValue = JsonLDPrimitive | JsonLDPrimitive[] | JsonLDDocument
+
+      export type JsonLDDocument = {
+        '@type'?: string,
+        "name"?: JsonLDPropertyValue,
+        [property: string]: JsonLDPropertyValue
       }
 
       export interface ExpandedSchemaRepresentationItem {
         [schemaRef: string]: Array<
-            string |
+            boolean | string |  ExpandedSchemaRepresentationItem |
             {
               '@id'?: string;
               '@type'?: string;
-              '@value'?: string;
+              '@value'?: JsonLDPrimitive
             }
           >;
       }
