diff --git a/package-lock.json b/package-lock.json
index 46b2853..285faf0 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -17,7 +17,8 @@
         "remark-gfm": "^3.0.1",
         "remark-parse": "^10.0.1",
         "sqlite3": "^5.1.6",
-        "unist-util-select": "^4.0.3"
+        "unist-util-select": "^4.0.3",
+        "zod": "^3.22.4"
       },
       "bin": {
         "mddb": "dist/src/bin/index.js"
@@ -11325,6 +11326,14 @@
         "url": "https://github.com/sponsors/sindresorhus"
       }
     },
+    "node_modules/zod": {
+      "version": "3.22.4",
+      "resolved": "https://registry.npmjs.org/zod/-/zod-3.22.4.tgz",
+      "integrity": "sha512-iC+8Io04lddc+mVqQ9AZ7OQ2MrUKGN+oIQyq1vemgt46jwCwLfhq7/pwnBnNXXXZb8VTVLKwp9EDkx+ryxIWmg==",
+      "funding": {
+        "url": "https://github.com/sponsors/colinhacks"
+      }
+    },
     "node_modules/zwitch": {
       "version": "2.0.4",
       "resolved": "https://registry.npmjs.org/zwitch/-/zwitch-2.0.4.tgz",
diff --git a/package.json b/package.json
index 61400be..8082c49 100644
--- a/package.json
+++ b/package.json
@@ -52,7 +52,8 @@
     "remark-gfm": "^3.0.1",
     "remark-parse": "^10.0.1",
     "sqlite3": "^5.1.6",
-    "unist-util-select": "^4.0.3"
+    "unist-util-select": "^4.0.3",
+    "zod": "^3.22.4"
   },
   "devDependencies": {
     "@changesets/changelog-github": "^0.4.8",
diff --git a/src/lib/CustomConfig.ts b/src/lib/CustomConfig.ts
index a92ae92..32ca29d 100644
--- a/src/lib/CustomConfig.ts
+++ b/src/lib/CustomConfig.ts
@@ -1,6 +1,11 @@
 import { FileInfo } from "./process.js";
 import { Root } from "remark-parse/lib/index.js";
+import { ZodObject } from "zod";
+
+type ComputedFields = ((fileInfo: FileInfo, ast: Root) => any)[];
+type Schemas = { [index: string]: ZodObject<any> };
 
 export interface CustomConfig {
-  computedFields?: ((fileInfo: FileInfo, ast: Root) => any)[];
+  computedFields?: ComputedFields;
+  schemas?: Schemas;
 }
diff --git a/src/lib/indexFolder.ts b/src/lib/indexFolder.ts
index cccc331..52a839d 100644
--- a/src/lib/indexFolder.ts
+++ b/src/lib/indexFolder.ts
@@ -1,3 +1,4 @@
+import { ZodError } from "zod";
 import { CustomConfig } from "./CustomConfig.js";
 import { FileInfo, processFile } from "./process.js";
 import { recursiveWalkDir } from "./recursiveWalkDir.js";
@@ -14,6 +15,7 @@ export function indexFolder(
   );
   const files: FileInfo[] = [];
   const computedFields = config.computedFields || [];
+  const schemas = config.schemas;
   for (const filePath of filteredFilePathsToIndex) {
     const fileObject = processFile(
       folderPath,
@@ -22,6 +24,33 @@ export function indexFolder(
       filePathsToIndex,
       computedFields
     );
+    const urlPath = fileObject?.url_path ?? "";
+    // This is temporary.
+    // Note: Subject to change pending agreement on the final structure of document types.
+    const flattenedFileObject = {
+      ...fileObject,
+      ...fileObject.metadata,
+      tags: fileObject.tags, // Don't override the tags
+    };
+    const documentType = urlPath.split("/")[0];
+
+    if (schemas && schemas[documentType]) {
+      const result = schemas[documentType].safeParse(flattenedFileObject);
+
+      if (!result.success) {
+        const error: ZodError = (result as any).error;
+
+        error.errors.forEach((err) => {
+          const errorMessage = `Error: In ${
+            fileObject.file_path
+          } for the ${documentType} schema. \n    In "${err.path.join(
+            ","
+          )}" field: ${err.message}`;
+          console.error(errorMessage);
+        });
+      }
+    }
+
     files.push(fileObject);
   }
   return files;