diff --git a/packages/kg-card-factory/.gitignore b/packages/kg-card-factory/.gitignore
new file mode 100644
index 0000000000..0264be4400
--- /dev/null
+++ b/packages/kg-card-factory/.gitignore
@@ -0,0 +1,2 @@
+build/
+tsconfig.tsbuildinfo
diff --git a/packages/kg-card-factory/eslint.config.mjs b/packages/kg-card-factory/eslint.config.mjs
index d43dd6ed67..49b87a9339 100644
--- a/packages/kg-card-factory/eslint.config.mjs
+++ b/packages/kg-card-factory/eslint.config.mjs
@@ -1,42 +1,33 @@
-import {fixupPluginRules} from '@eslint/compat';
+import {defineConfig} from 'eslint/config';
 import eslint from '@eslint/js';
 import ghostPlugin from 'eslint-plugin-ghost';
-import globals from 'globals';
+import tseslint from 'typescript-eslint';
 
-const ghost = fixupPluginRules(ghostPlugin);
-
-export default [
+export default defineConfig([
     {ignores: ['build/**']},
-    eslint.configs.recommended,
     {
-        files: ['**/*.js'],
-        plugins: {ghost},
+        files: ['**/*.ts'],
+        extends: [
+            eslint.configs.recommended,
+            tseslint.configs.recommended
+        ],
         languageOptions: {
-            globals: globals.node
+            parserOptions: {ecmaVersion: 2022, sourceType: 'module'}
         },
+        plugins: {ghost: ghostPlugin},
         rules: {
-            ...ghostPlugin.configs.node.rules,
-            // match ESLint 8 behavior for catch clause variables
-            'no-unused-vars': ['error', {caughtErrors: 'none'}],
-            // disable rules incompatible with ESLint 9 flat config
-            'ghost/filenames/match-exported-class': 'off',
-            'ghost/filenames/match-exported': 'off',
-            'ghost/filenames/match-regex': 'off'
+            ...ghostPlugin.configs.ts.rules,
+            '@typescript-eslint/no-explicit-any': 'error'
         }
     },
     {
-        files: ['test/**/*.js'],
-        plugins: {ghost},
-        languageOptions: {
-            globals: {
-                ...globals.node,
-                ...globals.mocha,
-                should: true,
-                sinon: true
-            }
-        },
+        files: ['test/**/*.ts'],
         rules: {
-            ...ghostPlugin.configs.test.rules
+            ...ghostPlugin.configs['ts-test'].rules,
+            'ghost/mocha/no-global-tests': 'off',
+            'ghost/mocha/handle-done-callback': 'off',
+            'ghost/mocha/no-mocha-arrows': 'off',
+            'ghost/mocha/max-top-level-suites': 'off'
         }
     }
-];
+]);
diff --git a/packages/kg-card-factory/index.js b/packages/kg-card-factory/index.js
deleted file mode 100644
index 3836faa527..0000000000
--- a/packages/kg-card-factory/index.js
+++ /dev/null
@@ -1 +0,0 @@
-module.exports = require('./lib/CardFactory');
diff --git a/packages/kg-card-factory/lib/CardFactory.js b/packages/kg-card-factory/lib/CardFactory.js
deleted file mode 100644
index 1763f3c56c..0000000000
--- a/packages/kg-card-factory/lib/CardFactory.js
+++ /dev/null
@@ -1,86 +0,0 @@
-module.exports = class CardFactory {
-    constructor(options) {
-        this.factoryOptions = options;
-    }
-
-    createCard(card) {
-        const {factoryOptions} = this;
-
-        const {
-            name,
-            type,
-            config = {}
-        } = card;
-
-        return {
-            name,
-            type,
-            factoryOptions,
-
-            render({env, payload, options}) {
-                const {dom} = env;
-                const cardOptions = Object.assign({}, factoryOptions, options);
-
-                const cardOutput = card.render({env, payload, options: cardOptions});
-
-                if (cardOutput.nodeType === 3 && cardOutput.nodeValue === '') {
-                    return cardOutput;
-                }
-
-                if (config.commentWrapper) {
-                    const cleanName = name.replace(/^card-/, '');
-                    const beginComment = dom.createComment(`kg-card-begin: ${cleanName}`);
-                    const endComment = dom.createComment(`kg-card-end: ${cleanName}`);
-                    const fragment = dom.createDocumentFragment();
-
-                    fragment.appendChild(beginComment);
-                    fragment.appendChild(cardOutput);
-                    fragment.appendChild(endComment);
-
-                    return fragment;
-                }
-
-                return cardOutput;
-            },
-
-            absoluteToRelative(payload, _options) {
-                if (card.absoluteToRelative) {
-                    const defaultOptions = {
-                        assetsOnly: false,
-                        siteUrl: factoryOptions.siteUrl
-                    };
-                    const options = Object.assign({}, defaultOptions, _options);
-                    return card.absoluteToRelative(payload, options);
-                }
-
-                return payload;
-            },
-
-            relativeToAbsolute(payload, _options) {
-                if (card.relativeToAbsolute) {
-                    const defaultOptions = {
-                        assetsOnly: false,
-                        siteUrl: factoryOptions.siteUrl
-                    };
-                    const options = Object.assign({}, defaultOptions, _options);
-                    return card.relativeToAbsolute(payload, options);
-                }
-
-                return payload;
-            },
-
-            toTransformReady(payload, _options) {
-                if (card.toTransformReady) {
-                    const defaultOptions = {
-                        assetsOnly: false,
-                        siteUrl: factoryOptions.siteUrl
-                    };
-                    const options = Object.assign({}, defaultOptions, _options);
-                    return card.toTransformReady(payload, options);
-                }
-
-                return payload;
-            }
-        };
-    }
-};
diff --git a/packages/kg-card-factory/package.json b/packages/kg-card-factory/package.json
index 7931978a49..29210b7cac 100644
--- a/packages/kg-card-factory/package.json
+++ b/packages/kg-card-factory/package.json
@@ -1,13 +1,25 @@
 {
   "name": "@tryghost/kg-card-factory",
   "version": "5.1.12",
-  "repository": "https://github.com/TryGhost/Koenig/tree/master/packages/kg-card-factory",
+  "repository": "https://github.com/TryGhost/Koenig/tree/main/packages/kg-card-factory",
   "author": "Ghost Foundation",
   "license": "MIT",
-  "main": "index.js",
+  "main": "build/cjs/index.js",
+  "module": "build/esm/index.js",
+  "types": "build/esm/index.d.ts",
+  "exports": {
+    ".": {
+      "types": "./build/esm/index.d.ts",
+      "import": "./build/esm/index.js",
+      "require": "./build/cjs/index.js"
+    }
+  },
   "scripts": {
     "dev": "echo \"Implement me!\"",
-    "test": "NODE_ENV=testing c8 --all --reporter text --reporter cobertura mocha './test/**/*.test.js'",
+    "build": "tsc && tsc -p tsconfig.cjs.json && echo '{\"type\":\"module\"}' > build/esm/package.json",
+    "prepare": "tsc && tsc -p tsconfig.cjs.json && echo '{\"type\":\"module\"}' > build/esm/package.json",
+    "pretest": "tsc && tsc -p tsconfig.cjs.json && echo '{\"type\":\"module\"}' > build/esm/package.json && tsc -p tsconfig.test.json",
+    "test": "NODE_ENV=testing c8 --all --reporter text --reporter cobertura mocha --require tsx './test/**/*.test.ts'",
     "lint": "eslint . --cache",
     "posttest": "yarn lint"
   },
@@ -15,17 +27,24 @@
     "node": "^22.13.1 || ^24.0.0"
   },
   "files": [
-    "index.js",
-    "lib"
+    "build"
   ],
   "publishConfig": {
     "access": "public"
   },
   "devDependencies": {
+    "@eslint/js": "9.39.4",
+    "@types/mocha": "10.0.10",
+    "@types/node": "22.15.29",
+    "@types/should": "13.0.0",
+    "@types/sinon": "17.0.4",
     "c8": "11.0.0",
     "mocha": "11.7.5",
     "should": "13.2.3",
     "simple-dom": "1.4.0",
-    "sinon": "21.0.2"
+    "sinon": "21.0.2",
+    "tsx": "4.19.4",
+    "typescript": "5.9.3",
+    "typescript-eslint": "8.33.1"
   }
 }
diff --git a/packages/kg-card-factory/src/CardFactory.ts b/packages/kg-card-factory/src/CardFactory.ts
new file mode 100644
index 0000000000..b3d5b0a905
--- /dev/null
+++ b/packages/kg-card-factory/src/CardFactory.ts
@@ -0,0 +1,119 @@
+export interface FactoryOptions {
+    siteUrl?: string;
+    [key: string]: unknown;
+}
+
+export interface CardPayload {
+    [key: string]: unknown;
+}
+
+export interface CardTransformOptions {
+    assetsOnly?: boolean;
+    siteUrl?: string;
+    [key: string]: unknown;
+}
+
+export interface DomNode {
+    nodeType?: number;
+    nodeValue?: string;
+    appendChild?(child: unknown): void;
+    [key: string]: unknown;
+}
+
+export interface DomProvider {
+    createComment(text: string): DomNode;
+    createDocumentFragment(): DomNode;
+    createElement?(tag: string): DomNode;
+    createTextNode?(text: string): DomNode;
+    [key: string]: unknown;
+}
+
+export interface CardRenderEnv {
+    dom: DomProvider;
+    [key: string]: unknown;
+}
+
+export interface CardRenderArgs {
+    env: CardRenderEnv;
+    payload: CardPayload;
+    options?: Record<string, unknown>;
+}
+
+export interface CardDefinition {
+    name: string;
+    type: string;
+    config?: { commentWrapper?: boolean };
+    render(args: CardRenderArgs): DomNode;
+    absoluteToRelative?(payload: CardPayload, options: CardTransformOptions): CardPayload;
+    relativeToAbsolute?(payload: CardPayload, options: CardTransformOptions): CardPayload;
+    toTransformReady?(payload: CardPayload, options: CardTransformOptions): CardPayload;
+}
+
+export default class CardFactory {
+    factoryOptions: FactoryOptions;
+
+    constructor(options: FactoryOptions = {}) {
+        this.factoryOptions = options;
+    }
+
+    createCard(card: CardDefinition) {
+        const {factoryOptions} = this;
+        const {name, type, config = {}} = card;
+
+        return {
+            name,
+            type,
+            factoryOptions,
+
+            render({env, payload, options}: CardRenderArgs): DomNode {
+                const {dom} = env;
+                const cardOptions = Object.assign({}, factoryOptions, options);
+                const cardOutput = card.render({env, payload, options: cardOptions});
+
+                if (cardOutput.nodeType === 3 && cardOutput.nodeValue === '') {
+                    return cardOutput;
+                }
+
+                if (config.commentWrapper) {
+                    const cleanName = name.replace(/^card-/, '');
+                    const beginComment = dom.createComment(`kg-card-begin: ${cleanName}`);
+                    const endComment = dom.createComment(`kg-card-end: ${cleanName}`);
+                    const fragment = dom.createDocumentFragment();
+                    fragment.appendChild!(beginComment);
+                    fragment.appendChild!(cardOutput);
+                    fragment.appendChild!(endComment);
+                    return fragment;
+                }
+
+                return cardOutput;
+            },
+
+            absoluteToRelative(payload: CardPayload, _options?: CardTransformOptions) {
+                if (card.absoluteToRelative) {
+                    const defaultOptions = {assetsOnly: false, siteUrl: factoryOptions.siteUrl};
+                    const options = Object.assign({}, defaultOptions, _options);
+                    return card.absoluteToRelative(payload, options);
+                }
+                return payload;
+            },
+
+            relativeToAbsolute(payload: CardPayload, _options?: CardTransformOptions) {
+                if (card.relativeToAbsolute) {
+                    const defaultOptions = {assetsOnly: false, siteUrl: factoryOptions.siteUrl};
+                    const options = Object.assign({}, defaultOptions, _options);
+                    return card.relativeToAbsolute(payload, options);
+                }
+                return payload;
+            },
+
+            toTransformReady(payload: CardPayload, _options?: CardTransformOptions) {
+                if (card.toTransformReady) {
+                    const defaultOptions = {assetsOnly: false, siteUrl: factoryOptions.siteUrl};
+                    const options = Object.assign({}, defaultOptions, _options);
+                    return card.toTransformReady(payload, options);
+                }
+                return payload;
+            }
+        };
+    }
+}
diff --git a/packages/kg-card-factory/src/index.ts b/packages/kg-card-factory/src/index.ts
new file mode 100644
index 0000000000..9b46dfe533
--- /dev/null
+++ b/packages/kg-card-factory/src/index.ts
@@ -0,0 +1,2 @@
+export {default} from './CardFactory.js';
+export type {FactoryOptions, CardPayload, CardTransformOptions, CardRenderEnv, CardRenderArgs, CardDefinition} from './CardFactory.js';
diff --git a/packages/kg-card-factory/test/CardFactory.test.js b/packages/kg-card-factory/test/CardFactory.test.js
deleted file mode 100644
index 0de9a1b6f1..0000000000
--- a/packages/kg-card-factory/test/CardFactory.test.js
+++ /dev/null
@@ -1,88 +0,0 @@
-// Switch these lines once there are useful utils
-// const testUtils = require('./utils');
-require('./utils');
-
-const CardFactory = require('../');
-const SimpleDom = require('simple-dom');
-const serializer = new SimpleDom.HTMLSerializer(SimpleDom.voidMap);
-
-describe('CardFactory', function () {
-    describe('render', function () {
-        it('adds comment wrapper when configured', function () {
-            let cardDefinition = {
-                name: 'test',
-                type: 'dom',
-                config: {
-                    commentWrapper: true
-                },
-                render({env: {dom}}) {
-                    let div = dom.createElement('div');
-                    div.appendChild(dom.createTextNode('Test!'));
-                    return div;
-                }
-            };
-            let factory = new CardFactory();
-            let card = factory.createCard(cardDefinition);
-
-            let opts = {
-                env: {
-                    dom: new SimpleDom.Document()
-                }
-            };
-
-            serializer.serialize(card.render(opts))
-                .should.eql('<!--kg-card-begin: test--><div>Test!</div><!--kg-card-end: test-->');
-        });
-
-        it('skips comment wrapper if card output is blank', function () {
-            let cardDefinition = {
-                name: 'test',
-                type: 'dom',
-                config: {
-                    commentWrapper: true
-                },
-                render({env: {dom}}) {
-                    return dom.createTextNode('');
-                }
-            };
-            let factory = new CardFactory();
-            let card = factory.createCard(cardDefinition);
-
-            let opts = {
-                env: {
-                    dom: new SimpleDom.Document()
-                }
-            };
-
-            serializer.serialize(card.render(opts)).should.eql('');
-        });
-    });
-
-    describe('absoluteToRelative', function () {
-        it('passes siteUrl in from factory options', function () {
-            let cardDefinition = {
-                absoluteToRelative(payload, options) {
-                    return options.siteUrl;
-                }
-            };
-            let factory = new CardFactory({siteUrl: 'http://127.0.0.1:2368/'});
-            let card = factory.createCard(cardDefinition);
-
-            card.absoluteToRelative().should.equal('http://127.0.0.1:2368/');
-        });
-    });
-
-    describe('relativeToAbsolute', function () {
-        it('passes siteUrl in from factory options', function () {
-            let cardDefinition = {
-                relativeToAbsolute(payload, options) {
-                    return options.siteUrl;
-                }
-            };
-            let factory = new CardFactory({siteUrl: 'http://127.0.0.1:2368/'});
-            let card = factory.createCard(cardDefinition);
-
-            card.relativeToAbsolute().should.equal('http://127.0.0.1:2368/');
-        });
-    });
-});
diff --git a/packages/kg-card-factory/test/CardFactory.test.ts b/packages/kg-card-factory/test/CardFactory.test.ts
new file mode 100644
index 0000000000..a1a6a9f810
--- /dev/null
+++ b/packages/kg-card-factory/test/CardFactory.test.ts
@@ -0,0 +1,83 @@
+import './utils/index.js';
+import CardFactory from '../src/CardFactory.js';
+import type {DomProvider} from '../src/CardFactory.js';
+import {Document as SimpleDomDocument, HTMLSerializer, voidMap} from 'simple-dom';
+
+const serializer = new HTMLSerializer(voidMap);
+
+describe('CardFactory', function () {
+    describe('render', function () {
+        it('adds comment wrapper when configured', function () {
+            const factory = new CardFactory();
+            const card = factory.createCard({
+                name: 'test',
+                type: 'dom',
+                config: {commentWrapper: true},
+                render({env: {dom}}) {
+                    const d = dom as DomProvider & InstanceType<typeof SimpleDomDocument>;
+                    const div = d.createElement('div');
+                    div.appendChild!(d.createTextNode('Test!'));
+                    return div;
+                }
+            });
+
+            const opts = {env: {dom: new SimpleDomDocument() as unknown as DomProvider}, payload: {}, options: {}};
+
+            serializer.serialize(card.render(opts) as unknown as Parameters<typeof serializer.serialize>[0])
+                .should.eql('<!--kg-card-begin: test--><div>Test!</div><!--kg-card-end: test-->');
+        });
+
+        it('skips comment wrapper if card output is blank', function () {
+            const factory = new CardFactory();
+            const card = factory.createCard({
+                name: 'test',
+                type: 'dom',
+                config: {commentWrapper: true},
+                render({env: {dom}}) {
+                    const d = dom as DomProvider & InstanceType<typeof SimpleDomDocument>;
+                    return d.createTextNode('');
+                }
+            });
+
+            const opts = {env: {dom: new SimpleDomDocument() as unknown as DomProvider}, payload: {}, options: {}};
+
+            serializer.serialize(card.render(opts) as unknown as Parameters<typeof serializer.serialize>[0]).should.eql('');
+        });
+    });
+
+    describe('absoluteToRelative', function () {
+        it('passes siteUrl in from factory options', function () {
+            const factory = new CardFactory({siteUrl: 'http://127.0.0.1:2368/'});
+            const card = factory.createCard({
+                name: 'test',
+                type: 'dom',
+                render() {
+                    return {};
+                },
+                absoluteToRelative(_payload, options) {
+                    return {receivedSiteUrl: options.siteUrl};
+                }
+            });
+
+            card.absoluteToRelative({}).should.have.property('receivedSiteUrl', 'http://127.0.0.1:2368/');
+        });
+    });
+
+    describe('relativeToAbsolute', function () {
+        it('passes siteUrl in from factory options', function () {
+            const factory = new CardFactory({siteUrl: 'http://127.0.0.1:2368/'});
+            const card = factory.createCard({
+                name: 'test',
+                type: 'dom',
+                render() {
+                    return {};
+                },
+                relativeToAbsolute(_payload, options) {
+                    return {receivedSiteUrl: options.siteUrl};
+                }
+            });
+
+            card.relativeToAbsolute({}).should.have.property('receivedSiteUrl', 'http://127.0.0.1:2368/');
+        });
+    });
+});
diff --git a/packages/kg-card-factory/test/utils/assertions.js b/packages/kg-card-factory/test/utils/assertions.ts
similarity index 100%
rename from packages/kg-card-factory/test/utils/assertions.js
rename to packages/kg-card-factory/test/utils/assertions.ts
diff --git a/packages/kg-card-factory/test/utils/index.js b/packages/kg-card-factory/test/utils/index.ts
similarity index 76%
rename from packages/kg-card-factory/test/utils/index.js
rename to packages/kg-card-factory/test/utils/index.ts
index 0d67d86ff8..f385b7bf56 100644
--- a/packages/kg-card-factory/test/utils/index.js
+++ b/packages/kg-card-factory/test/utils/index.ts
@@ -5,7 +5,7 @@
  */
 
 // Require overrides - these add globals for tests
-require('./overrides');
+import './overrides.js';
 
 // Require assertions - adds custom should assertions
-require('./assertions');
+import './assertions.js';
diff --git a/packages/kg-card-factory/test/utils/overrides.js b/packages/kg-card-factory/test/utils/overrides.js
deleted file mode 100644
index 90203424ee..0000000000
--- a/packages/kg-card-factory/test/utils/overrides.js
+++ /dev/null
@@ -1,10 +0,0 @@
-// This file is required before any test is run
-
-// Taken from the should wiki, this is how to make should global
-// Should is a global in our eslint test config
-global.should = require('should').noConflict();
-should.extend();
-
-// Sinon is a simple case
-// Sinon is a global in our eslint test config
-global.sinon = require('sinon');
diff --git a/packages/kg-card-factory/test/utils/overrides.ts b/packages/kg-card-factory/test/utils/overrides.ts
new file mode 100644
index 0000000000..6138e929ff
--- /dev/null
+++ b/packages/kg-card-factory/test/utils/overrides.ts
@@ -0,0 +1,15 @@
+// This file is required before any test is run
+
+// Taken from the should wiki, this is how to make should global
+// Should is a global in our eslint test config
+import should from 'should';
+import sinon from 'sinon';
+
+// @types/should is incomplete — noConflict and extend exist at runtime
+const shouldModule = should as unknown as {noConflict(): typeof should; extend(): void};
+Object.defineProperty(globalThis, 'should', {value: shouldModule.noConflict(), writable: true, configurable: true});
+shouldModule.extend();
+
+// Sinon is a simple case
+// Sinon is a global in our eslint test config
+Object.defineProperty(globalThis, 'sinon', {value: sinon, writable: true, configurable: true});
diff --git a/packages/kg-card-factory/tsconfig.cjs.json b/packages/kg-card-factory/tsconfig.cjs.json
new file mode 100644
index 0000000000..bd981491bc
--- /dev/null
+++ b/packages/kg-card-factory/tsconfig.cjs.json
@@ -0,0 +1,13 @@
+{
+  "extends": "./tsconfig.json",
+  "compilerOptions": {
+    "module": "NodeNext",
+    "moduleResolution": "NodeNext",
+    "outDir": "build/cjs",
+    "verbatimModuleSyntax": false,
+    "declaration": false,
+    "declarationMap": false,
+    "sourceMap": false,
+    "incremental": false
+  }
+}
diff --git a/packages/kg-card-factory/tsconfig.json b/packages/kg-card-factory/tsconfig.json
new file mode 100644
index 0000000000..e2ebf36cde
--- /dev/null
+++ b/packages/kg-card-factory/tsconfig.json
@@ -0,0 +1,22 @@
+{
+    "compilerOptions": {
+        "target": "es2022",
+        "module": "ES2022",
+        "moduleResolution": "bundler",
+        "rootDir": "src",
+        "outDir": "build/esm",
+        "strict": true,
+        "declaration": true,
+        "declarationMap": true,
+        "sourceMap": true,
+        "incremental": true,
+        "esModuleInterop": true,
+        "forceConsistentCasingInFileNames": true,
+        "skipLibCheck": true,
+        "resolveJsonModule": true,
+        "isolatedModules": true
+    },
+    "include": [
+        "src/**/*"
+    ]
+}
diff --git a/packages/kg-card-factory/tsconfig.test.json b/packages/kg-card-factory/tsconfig.test.json
new file mode 100644
index 0000000000..b092804ad8
--- /dev/null
+++ b/packages/kg-card-factory/tsconfig.test.json
@@ -0,0 +1,16 @@
+{
+    "extends": "./tsconfig.json",
+    "compilerOptions": {
+        "rootDir": ".",
+        "outDir": null,
+        "noEmit": true,
+        "declaration": false,
+        "declarationMap": false,
+        "sourceMap": false,
+        "incremental": false
+    },
+    "include": [
+        "src/**/*",
+        "test/**/*"
+    ]
+}