diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 4b2b273..bb009c4 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -247,6 +247,7 @@ this.createError(
 #### Adding to the core library
 
 * You should write a test for your rule.
+* Add the rule's file, as well as its test file to tsconfig.json's `include` array, so that TypeScript can check for errors.
 * Add the rule to the list in `rules/index`, so that it is processed.
 
 #### Adding to your own application
diff --git a/README.md b/README.md
index 27bfbe3..3888114 100644
--- a/README.md
+++ b/README.md
@@ -229,10 +229,10 @@ To run tests locally, run:
 $ npm test
 ```
 
-The test run will also include a run of [eslint](https://eslint.org/). To run the tests without these, use:
+The test run will also include a run of [eslint](https://eslint.org/) and [TypeScript](https://www.typescriptlang.org/). To run the tests without these, use:
 
 ```shell
-$ npm run test-no-lint
+$ npm run run-tests
 ```
 
 ### Contributing
diff --git a/package.json b/package.json
index 30d6ce1..9837dd4 100644
--- a/package.json
+++ b/package.json
@@ -38,19 +38,23 @@
     "write-file-atomic": "^3.0.3"
   },
   "devDependencies": {
+    "@types/jasmine": "^5.1.4",
+    "@types/jasmine-expect": "^3.8.1",
+    "@types/node": "^20.11.24",
     "eslint": "^8.36.0",
     "eslint-config-airbnb": "^19.0.4",
     "eslint-plugin-import": "^2.27.5",
     "jasmine": "^4.6.0",
     "nock": "^13.3.0",
-    "sync-request": "^6.1.0"
+    "sync-request": "^6.1.0",
+    "typescript": "^5.3.3"
   },
   "scripts": {
     "lint": "eslint \"src/**/*.js\"",
     "lint-fix": "eslint \"src/**/*.js\" --fix",
-    "pretest": "npm run lint",
-    "test": "npm run test-no-lint",
-    "test-no-lint": "jasmine",
+    "pretest": "npm run lint && tsc",
+    "test": "npm run run-tests",
+    "run-tests": "jasmine",
     "test-debug": "node --inspect-brk -i ./node_modules/jasmine/bin/jasmine.js",
     "postpublish": "git push",
     "publish-patch": "npm test && git pull && git push && npm version patch && npm publish"
diff --git a/src/classes/field.js b/src/classes/field.js
index 776be3d..0a265b9 100644
--- a/src/classes/field.js
+++ b/src/classes/field.js
@@ -301,7 +301,9 @@ const Field = class {
       actualTypeKey = actualTypeKey.substr(1);
     }
     if (
+      // @ts-expect-error
       typeof (this.constructor.canBeTypeOfMapping[testTypeKey]) !== 'undefined'
+      // @ts-expect-error
       && this.constructor.canBeTypeOfMapping[testTypeKey] === actualTypeKey
     ) {
       return true;
diff --git a/src/classes/model-node.js b/src/classes/model-node.js
index 618288c..73866c9 100644
--- a/src/classes/model-node.js
+++ b/src/classes/model-node.js
@@ -128,6 +128,7 @@ const ModelNode = class {
       // Does our property allow us to inherit?
       && typeof this.parentNode.model.fields[this.cleanName] !== 'undefined'
       && typeof this.parentNode.model.fields[this.cleanName].inheritsTo !== 'undefined'
+      // @ts-expect-error
       && this.constructor.checkInheritRule(
         this.parentNode.model.fields[this.cleanName].inheritsTo,
         field,
@@ -142,6 +143,7 @@ const ModelNode = class {
           const modelField = this.model.fields[fieldKey];
           const fieldValue = this.getValue(fieldKey);
           if (typeof modelField.inheritsFrom !== 'undefined'
+            // @ts-expect-error
             && this.constructor.checkInheritRule(modelField.inheritsFrom, field)
             && typeof fieldValue === 'object'
             && !(fieldValue instanceof Array)
@@ -162,6 +164,7 @@ const ModelNode = class {
               }
             }
             if (parentModel) {
+              // @ts-expect-error
               const parentNode = new this.constructor(
                 modelField.fieldName,
                 fieldValue,
diff --git a/src/classes/model.js b/src/classes/model.js
index 490415d..596a224 100644
--- a/src/classes/model.js
+++ b/src/classes/model.js
@@ -80,6 +80,7 @@ const Model = class {
   }
 
   hasRequiredField(field) {
+    // @ts-expect-error
     return PropertyHelper.arrayHasField(this.requiredFields, field, this.version);
   }
 
@@ -143,6 +144,7 @@ const Model = class {
   }
 
   hasRecommendedField(field) {
+    // @ts-expect-error
     return PropertyHelper.arrayHasField(this.recommendedFields, field, this.version);
   }
 
diff --git a/src/helpers/json-loader.js b/src/helpers/json-loader.js
index 44fd9fa..2f6e082 100644
--- a/src/helpers/json-loader.js
+++ b/src/helpers/json-loader.js
@@ -99,6 +99,7 @@ async function getFromFsCacheIfExists(baseCachePath, url) {
     // Probably just doesn't exist
     return { exists: false };
   }
+  // @ts-expect-error
   const parsed = JSON.parse(rawCacheContents);
   return {
     exists: true,
@@ -132,6 +133,7 @@ async function saveToFsCache(baseCachePath, url, fileObject) {
 async function getFromRemoteUrl(url) {
   let response;
   try {
+    // @ts-expect-error
     response = await axios.get(url, {
       headers: {
         'Content-Type': 'application/ld+json',
@@ -146,6 +148,7 @@ async function getFromRemoteUrl(url) {
       if (match !== null) {
         const { origin } = new URL(url);
         const linkUrl = match[1];
+        // @ts-expect-error
         response = await axios.get(origin + linkUrl, {
           headers: {
             'Content-Type': 'application/ld+json',
@@ -217,7 +220,7 @@ async function getFileLoadRemote(url) {
  *
  * @param {string} url
  * @param {Object} options
- * @returns {Object}
+ * @returns {Promise<any>}
  */
 async function getFileLoadRemoteAndCacheToFs(url, options) {
   {
diff --git a/src/rules/rule.js b/src/rules/rule.js
index 1daceb3..c1b1519 100644
--- a/src/rules/rule.js
+++ b/src/rules/rule.js
@@ -5,9 +5,26 @@ const ValidationError = require('../errors/validation-error');
 class Rule {
   constructor(options) {
     this.options = options || new OptionsHelper();
+    /** @type {string[] | '*'} */
     this.targetModels = [];
+    /** @type {'*' | {[model: string]: '*' | string[]}} */
     this.targetFields = {};
+    /** @type {string[] | '*'} */
     this.targetValidationModes = '*';
+    /**
+     * @type {{
+     *   name: string;
+     *   description: string;
+     *   tests: {[key: string]: {
+     *     description?: string;
+     *     message: string;
+     *     sampleValues?: { [messageTemplateArg: string]: string };
+     *     category: string;
+     *     severity: string;
+     *     type: string;
+     *   }}
+     * }}
+     */
     this.meta = {
       name: 'Rule',
       description: 'This is a base rule description that should be overridden.',
@@ -38,11 +55,22 @@ class Rule {
     return errors;
   }
 
-  validateModel(/* node */) {
+  /**
+   * @param {import('../classes/model-node').ModelNodeType} node
+   * @returns {Promise<import('../errors/validation-error')[]>}
+   */
+  // eslint-disable-next-line no-unused-vars
+  validateModel(node) {
     throw Error('Model validation rule not implemented');
   }
 
-  async validateField(/* node, field */) {
+  /**
+   * @param {import('../classes/model-node').ModelNodeType} node
+   * @param {string} field
+   * @returns {Promise<import('../errors/validation-error')[]>}
+   */
+  // eslint-disable-next-line no-unused-vars
+  async validateField(node, field) {
     throw Error('Field validation rule not implemented');
   }
 
@@ -88,6 +116,10 @@ class Rule {
     );
   }
 
+  /**
+   * @param {import('../classes/model')} model
+   * @param {string} field
+   */
   isFieldTargeted(model, field) {
     if (this.targetFields === '*') {
       return true;
diff --git a/tsconfig.json b/tsconfig.json
new file mode 100644
index 0000000..a3b356a
--- /dev/null
+++ b/tsconfig.json
@@ -0,0 +1,22 @@
+{
+  "compilerOptions": {
+    "noEmit": true,
+    "allowJs": true,
+    "checkJs": true,
+    "downlevelIteration": true,
+    "target": "ES2019",
+    "moduleResolution": "node",
+    "types": ["jasmine", "node", "jasmine-expect"]
+  },
+  "include": [
+    "src/classes/**/*.js",
+    "src/errors/**/*.js",
+    "src/helpers/**/*.js",
+    "src/rules/rule.js",
+    // TODO add other rules
+    "src/exceptions.js"
+  ],
+  "exclude": [
+    "src/helpers/graph.js"
+  ]
+}