diff --git a/packages/tpl/.gitignore b/packages/tpl/.gitignore
new file mode 100644
index 000000000..da0a0baf7
--- /dev/null
+++ b/packages/tpl/.gitignore
@@ -0,0 +1,6 @@
+index.js
+index.d.ts
+index.js.map
+lib/*.js
+lib/*.d.ts
+lib/*.js.map
diff --git a/packages/tpl/index.js b/packages/tpl/index.js
deleted file mode 100644
index bcbd8ac9b..000000000
--- a/packages/tpl/index.js
+++ /dev/null
@@ -1 +0,0 @@
-module.exports = require('./lib/tpl');
diff --git a/packages/tpl/index.ts b/packages/tpl/index.ts
new file mode 100644
index 000000000..d20fd9efb
--- /dev/null
+++ b/packages/tpl/index.ts
@@ -0,0 +1,3 @@
+import tpl = require('./lib/tpl');
+
+export = tpl;
diff --git a/packages/tpl/lib/tpl.js b/packages/tpl/lib/tpl.ts
similarity index 81%
rename from packages/tpl/lib/tpl.js
rename to packages/tpl/lib/tpl.ts
index 360812637..90059b9fe 100644
--- a/packages/tpl/lib/tpl.js
+++ b/packages/tpl/lib/tpl.ts
@@ -6,13 +6,8 @@ const interpolate = /(?<!{){([^{]+?)}/g;
  * Will ignore double or triple braces like {{get}} or {{{helpername}}}
  * Can handle escaped braces e.g. \\{\\{{helpername}\\}\\}
  * But there's a simple bare minimum escaping needed to make {{{helpername}}} work e.g. {\\{{helpername}}}
- *
- *
- * @param {String} string - string with optional {data properties}
- * @param {Object} [data] - optional data to interpolate
- * @returns {string} the interpolated string
  */
-module.exports = (string, data) => {
+function tpl(string: string, data?: object | null): string {
     if (!data) {
         return string;
     }
@@ -25,8 +20,10 @@ module.exports = (string, data) => {
         if (!(trimmed in data)) {
             throw new ReferenceError(`${trimmed} is not defined`);
         }
-        return data[trimmed];
+        return String((data as Record<string, unknown>)[trimmed]);
     });
     // Replace our swapped out left braces and any escaped right braces
     return processedString.replace(/\\U\+007B/g, '{').replace(/\\}/g, '}');
-};
+}
+
+export = tpl;
diff --git a/packages/tpl/package.json b/packages/tpl/package.json
index abadfafb1..f6cb13201 100644
--- a/packages/tpl/package.json
+++ b/packages/tpl/package.json
@@ -10,20 +10,28 @@
   },
   "files": [
     "index.js",
-    "lib"
+    "index.d.ts",
+    "lib/*.js",
+    "lib/*.d.ts"
   ],
   "main": "index.js",
+  "types": "index.d.ts",
   "publishConfig": {
     "access": "public"
   },
   "scripts": {
-    "dev": "echo \"Implement me!\"",
-    "test": "NODE_ENV=testing vitest run --coverage",
+    "dev": "tsc --watch --preserveWatchOutput --sourceMap",
+    "build": "tsc",
+    "prepare": "tsc",
+    "pretest": "pnpm run build",
+    "test": "pnpm run test:types && NODE_ENV=testing vitest run --coverage",
+    "test:types": "tsc -p tsconfig.test.json --noEmit",
     "lint": "oxlint -c ../../.oxlintrc.json .",
     "posttest": "pnpm run lint"
   },
   "dependencies": {},
   "devDependencies": {
-    "sinon": "catalog:"
+    "@types/node": "24.13.1",
+    "typescript": "catalog:"
   }
 }
diff --git a/packages/tpl/test/tpl.test.js b/packages/tpl/test/tpl.test.ts
similarity index 78%
rename from packages/tpl/test/tpl.test.js
rename to packages/tpl/test/tpl.test.ts
index 5d0b281ef..b80909750 100644
--- a/packages/tpl/test/tpl.test.js
+++ b/packages/tpl/test/tpl.test.ts
@@ -1,5 +1,5 @@
-const assert = require('assert/strict');
-const tpl = require('../');
+import assert from 'assert/strict';
+import tpl from '../';
 
 describe('tpl', function () {
     it('Can handle a plain string', function () {
@@ -13,7 +13,20 @@ describe('tpl', function () {
         const string = 'Go visit {url}';
         const data = { url: 'https://example.com' };
 
-        let result = tpl(string, data);
+        const result = tpl(string, data);
+
+        assert.equal(result, 'Go visit https://example.com');
+    });
+
+    it('Can handle typed data objects', function () {
+        interface TemplateData {
+            url: string;
+        }
+
+        const string = 'Go visit {url}';
+        const data: TemplateData = { url: 'https://example.com' };
+
+        const result = tpl(string, data);
 
         assert.equal(result, 'Go visit https://example.com');
     });
@@ -24,7 +37,7 @@ describe('tpl', function () {
             totalMs: '500',
         };
 
-        let result = tpl(string, data);
+        const result = tpl(string, data);
         assert.equal(result, '{{#get}} helper took 500ms to complete');
     });
 
@@ -36,7 +49,7 @@ describe('tpl', function () {
             totalMs: '500',
         };
 
-        let result = tpl(string, data);
+        const result = tpl(string, data);
         assert.equal(result, '{{#get}} helper took 500ms to complete');
     });
 
@@ -46,7 +59,7 @@ describe('tpl', function () {
             helperName: 'get',
             totalMs: '500',
         };
-        let result = tpl(string, data);
+        const result = tpl(string, data);
         assert.equal(result, 'The {{{helperName}}} helper is not available.');
     });
 
@@ -56,7 +69,7 @@ describe('tpl', function () {
             helperName: 'get',
             totalMs: '500',
         };
-        let result = tpl(string, data);
+        const result = tpl(string, data);
         assert.equal(result, 'The {{get}} helper is not available.');
     });
 
@@ -66,7 +79,7 @@ describe('tpl', function () {
             helperName: 'get',
             totalMs: '500',
         };
-        let result = tpl(string, data);
+        const result = tpl(string, data);
         assert.equal(result, 'The {{get}} helper is not available.');
     });
 
@@ -76,7 +89,7 @@ describe('tpl', function () {
             helperName: 'get',
             totalMs: '500',
         };
-        let result = tpl(string, data);
+        const result = tpl(string, data);
         assert.equal(result, 'The {{get}} helper is not available.');
     });
 
@@ -86,7 +99,7 @@ describe('tpl', function () {
             totalMs: '500',
         };
 
-        let resultFn = () => {
+        const resultFn = () => {
             tpl(string, data);
         };
         assert.throws(resultFn, /helperName is not defined/);
diff --git a/packages/tpl/tsconfig.json b/packages/tpl/tsconfig.json
new file mode 100644
index 000000000..c455e3036
--- /dev/null
+++ b/packages/tpl/tsconfig.json
@@ -0,0 +1,9 @@
+{
+  "extends": "../tsconfig.json",
+  "compilerOptions": {
+    "rootDir": ".",
+    "sourceMap": false,
+    "types": []
+  },
+  "include": ["index.ts", "lib/**/*.ts"]
+}
diff --git a/packages/tpl/tsconfig.test.json b/packages/tpl/tsconfig.test.json
new file mode 100644
index 000000000..885e5092e
--- /dev/null
+++ b/packages/tpl/tsconfig.test.json
@@ -0,0 +1,7 @@
+{
+  "extends": "./tsconfig.json",
+  "compilerOptions": {
+    "types": ["node", "vitest/globals"]
+  },
+  "include": ["index.ts", "lib/**/*.ts", "test/**/*.ts"]
+}
diff --git a/packages/tpl/vitest.config.ts b/packages/tpl/vitest.config.ts
new file mode 100644
index 000000000..10013bd29
--- /dev/null
+++ b/packages/tpl/vitest.config.ts
@@ -0,0 +1,14 @@
+import { defineConfig, mergeConfig } from 'vitest/config';
+import rootConfig from '../../vitest.config';
+
+export default mergeConfig(
+    rootConfig,
+    defineConfig({
+        test: {
+            coverage: {
+                include: ['lib/**/*.js'],
+                exclude: ['**/*.ts', '**/*.d.ts'],
+            },
+        },
+    }),
+);
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index ad5230ca0..39ee84d98 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -120,7 +120,7 @@ importers:
         version: link:../errors
       '@tryghost/nql':
         specifier: 0.13.1
-        version: 0.13.1
+        version: 0.13.1(supports-color@7.2.0)
       '@tryghost/tpl':
         specifier: workspace:*
         version: link:../tpl
@@ -273,7 +273,7 @@ importers:
     dependencies:
       '@elastic/elasticsearch':
         specifier: 8.19.1
-        version: 8.19.1
+        version: 8.19.1(supports-color@7.2.0)
       '@tryghost/debug':
         specifier: workspace:*
         version: link:../debug
@@ -326,7 +326,7 @@ importers:
     devDependencies:
       express:
         specifier: 5.2.1
-        version: 5.2.1
+        version: 5.2.1(supports-color@7.2.0)
       express-session:
         specifier: 1.19.0
         version: 1.19.0
@@ -354,7 +354,7 @@ importers:
     devDependencies:
       express:
         specifier: 5.2.1
-        version: 5.2.1
+        version: 5.2.1(supports-color@7.2.0)
       sinon:
         specifier: 'catalog:'
         version: 22.0.0
@@ -413,7 +413,7 @@ importers:
         version: 4.4.0
       rewire:
         specifier: 9.0.1
-        version: 9.0.1
+        version: 9.0.1(supports-color@7.2.0)
       sinon:
         specifier: 'catalog:'
         version: 22.0.0
@@ -475,7 +475,7 @@ importers:
     devDependencies:
       rewire:
         specifier: 9.0.1
-        version: 9.0.1
+        version: 9.0.1(supports-color@7.2.0)
       sinon:
         specifier: 'catalog:'
         version: 22.0.0
@@ -509,7 +509,7 @@ importers:
     devDependencies:
       supertest:
         specifier: 7.2.2
-        version: 7.2.2
+        version: 7.2.2(supports-color@7.2.0)
 
   packages/nodemailer:
     dependencies:
@@ -575,7 +575,7 @@ importers:
         version: link:../logging
       express:
         specifier: 5.2.1
-        version: 5.2.1
+        version: 5.2.1(supports-color@7.2.0)
       prom-client:
         specifier: 15.1.3
         version: 15.1.3
@@ -609,7 +609,7 @@ importers:
         version: 22.0.0
       supertest:
         specifier: 7.2.2
-        version: 7.2.2
+        version: 7.2.2(supports-color@7.2.0)
       typescript:
         specifier: 'catalog:'
         version: 6.0.3
@@ -646,7 +646,7 @@ importers:
         version: 14.0.15
       rewire:
         specifier: 9.0.1
-        version: 9.0.1
+        version: 9.0.1(supports-color@7.2.0)
       sinon:
         specifier: 'catalog:'
         version: 22.0.0
@@ -692,9 +692,12 @@ importers:
 
   packages/tpl:
     devDependencies:
-      sinon:
+      '@types/node':
+        specifier: 24.13.1
+        version: 24.13.1
+      typescript:
         specifier: 'catalog:'
-        version: 22.0.0
+        version: 6.0.3
 
   packages/validator:
     dependencies:
@@ -750,7 +753,7 @@ importers:
         version: 8.0.0
       extract-zip:
         specifier: 2.0.1
-        version: 2.0.1
+        version: 2.0.1(supports-color@7.2.0)
     devDependencies:
       folder-hash:
         specifier: 4.1.3
@@ -2385,6 +2388,9 @@ packages:
   '@types/methods@1.1.4':
     resolution: {integrity: sha512-ymXWVrDiCxTBE3+RIrrP533E70eA+9qu7zdWoHuOmGujkYtzf4HQF96b8nwHLqhuf4ykX61IGRIB38CC6/sImQ==}
 
+  '@types/node@24.13.1':
+    resolution: {integrity: sha512-RSpUJGmvsJ1ZeBehQZFhIdpsz+bIpES0nIQXko4Ybq+N+kX6XvOq3Jo+iJ82FWLdblFq85AsMikd3m35jgezYg==}
+
   '@types/node@24.13.2':
     resolution: {integrity: sha512-fRa09kZTgu8o71KFcDjUFuc7F+dEbZYZmkI0mg5YBTRs0yMKjYHsq/c0urDKeDb+D5qVgXOdFcuu+DZPKOITwA==}
 
@@ -6268,16 +6274,16 @@ snapshots:
 
   '@breejs/later@4.2.0': {}
 
-  '@elastic/elasticsearch@8.19.1':
+  '@elastic/elasticsearch@8.19.1(supports-color@7.2.0)':
     dependencies:
-      '@elastic/transport': 8.10.1
+      '@elastic/transport': 8.10.1(supports-color@7.2.0)
       apache-arrow: 21.1.0
       tslib: 2.8.1
     transitivePeerDependencies:
       - '@75lb/nature'
       - supports-color
 
-  '@elastic/transport@8.10.1':
+  '@elastic/transport@8.10.1(supports-color@7.2.0)':
     dependencies:
       '@opentelemetry/api': 1.9.1
       '@opentelemetry/core': 2.8.0(@opentelemetry/api@1.9.1)
@@ -6399,12 +6405,12 @@ snapshots:
 
   '@eslint-community/eslint-utils@4.9.1(eslint@9.39.4)':
     dependencies:
-      eslint: 9.39.4
+      eslint: 9.39.4(supports-color@7.2.0)
       eslint-visitor-keys: 3.4.3
 
   '@eslint-community/regexpp@4.12.2': {}
 
-  '@eslint/config-array@0.21.2':
+  '@eslint/config-array@0.21.2(supports-color@7.2.0)':
     dependencies:
       '@eslint/object-schema': 2.1.7
       debug: 4.4.3(supports-color@7.2.0)
@@ -6420,7 +6426,7 @@ snapshots:
     dependencies:
       '@types/json-schema': 7.0.15
 
-  '@eslint/eslintrc@3.3.5':
+  '@eslint/eslintrc@3.3.5(supports-color@7.2.0)':
     dependencies:
       ajv: 6.15.0
       debug: 4.4.3(supports-color@7.2.0)
@@ -6941,7 +6947,7 @@ snapshots:
     dependencies:
       long-timeout: 0.1.1
 
-  '@tryghost/mongo-knex@0.10.1':
+  '@tryghost/mongo-knex@0.10.1(supports-color@7.2.0)':
     dependencies:
       debug: 4.4.3(supports-color@7.2.0)
       lodash: 4.18.1
@@ -6956,9 +6962,9 @@ snapshots:
     dependencies:
       date-fns: 2.30.0
 
-  '@tryghost/nql@0.13.1':
+  '@tryghost/nql@0.13.1(supports-color@7.2.0)':
     dependencies:
-      '@tryghost/mongo-knex': 0.10.1
+      '@tryghost/mongo-knex': 0.10.1(supports-color@7.2.0)
       '@tryghost/mongo-utils': 0.6.5
       '@tryghost/nql-lang': 0.6.6
       lodash: 4.18.1
@@ -7036,6 +7042,10 @@ snapshots:
 
   '@types/methods@1.1.4': {}
 
+  '@types/node@24.13.1':
+    dependencies:
+      undici-types: 7.18.2
+
   '@types/node@24.13.2':
     dependencies:
       undici-types: 7.18.2
@@ -7417,7 +7427,7 @@ snapshots:
 
   bluebird@3.7.2: {}
 
-  body-parser@2.3.0:
+  body-parser@2.3.0(supports-color@7.2.0):
     dependencies:
       bytes: 3.1.2
       content-type: 2.0.0
@@ -7872,14 +7882,14 @@ snapshots:
 
   eslint-visitor-keys@4.2.1: {}
 
-  eslint@9.39.4:
+  eslint@9.39.4(supports-color@7.2.0):
     dependencies:
       '@eslint-community/eslint-utils': 4.9.1(eslint@9.39.4)
       '@eslint-community/regexpp': 4.12.2
-      '@eslint/config-array': 0.21.2
+      '@eslint/config-array': 0.21.2(supports-color@7.2.0)
       '@eslint/config-helpers': 0.4.2
       '@eslint/core': 0.17.0
-      '@eslint/eslintrc': 3.3.5
+      '@eslint/eslintrc': 3.3.5(supports-color@7.2.0)
       '@eslint/js': 9.39.4
       '@eslint/plugin-kit': 0.4.1
       '@humanfs/node': 0.16.8
@@ -7980,10 +7990,10 @@ snapshots:
     transitivePeerDependencies:
       - supports-color
 
-  express@5.2.1:
+  express@5.2.1(supports-color@7.2.0):
     dependencies:
       accepts: 2.0.0
-      body-parser: 2.3.0
+      body-parser: 2.3.0(supports-color@7.2.0)
       content-disposition: 1.1.0
       content-type: 1.0.5
       cookie: 0.7.2
@@ -7993,7 +8003,7 @@ snapshots:
       encodeurl: 2.0.0
       escape-html: 1.0.3
       etag: 1.8.1
-      finalhandler: 2.1.1
+      finalhandler: 2.1.1(supports-color@7.2.0)
       fresh: 2.0.0
       http-errors: 2.0.1
       merge-descriptors: 2.0.0
@@ -8004,8 +8014,8 @@ snapshots:
       proxy-addr: 2.0.7
       qs: 6.15.2
       range-parser: 1.2.1
-      router: 2.2.0
-      send: 1.2.1
+      router: 2.2.0(supports-color@7.2.0)
+      send: 1.2.1(supports-color@7.2.0)
       serve-static: 2.2.1
       statuses: 2.0.2
       type-is: 2.1.0
@@ -8013,7 +8023,7 @@ snapshots:
     transitivePeerDependencies:
       - supports-color
 
-  extract-zip@2.0.1:
+  extract-zip@2.0.1(supports-color@7.2.0):
     dependencies:
       debug: 4.4.3(supports-color@7.2.0)
       get-stream: 5.2.0
@@ -8055,7 +8065,7 @@ snapshots:
 
   file-uri-to-path@1.0.0: {}
 
-  finalhandler@2.1.1:
+  finalhandler@2.1.1(supports-color@7.2.0):
     dependencies:
       debug: 4.4.3(supports-color@7.2.0)
       encodeurl: 2.0.0
@@ -9408,9 +9418,9 @@ snapshots:
 
   reusify@1.1.0: {}
 
-  rewire@9.0.1:
+  rewire@9.0.1(supports-color@7.2.0):
     dependencies:
-      eslint: 9.39.4
+      eslint: 9.39.4(supports-color@7.2.0)
       pirates: 4.0.7
     transitivePeerDependencies:
       - jiti
@@ -9444,7 +9454,7 @@ snapshots:
       '@rolldown/binding-win32-arm64-msvc': 1.0.3
       '@rolldown/binding-win32-x64-msvc': 1.0.3
 
-  router@2.2.0:
+  router@2.2.0(supports-color@7.2.0):
     dependencies:
       debug: 4.4.3(supports-color@7.2.0)
       depd: 2.0.0
@@ -9475,7 +9485,7 @@ snapshots:
 
   semver@7.8.5: {}
 
-  send@1.2.1:
+  send@1.2.1(supports-color@7.2.0):
     dependencies:
       debug: 4.4.3(supports-color@7.2.0)
       encodeurl: 2.0.0
@@ -9496,7 +9506,7 @@ snapshots:
       encodeurl: 2.0.0
       escape-html: 1.0.3
       parseurl: 1.3.3
-      send: 1.2.1
+      send: 1.2.1(supports-color@7.2.0)
     transitivePeerDependencies:
       - supports-color
 
@@ -9659,7 +9669,7 @@ snapshots:
 
   strip-json-comments@3.1.1: {}
 
-  superagent@10.3.0:
+  superagent@10.3.0(supports-color@7.2.0):
     dependencies:
       component-emitter: 1.3.1
       cookiejar: 2.1.4
@@ -9673,11 +9683,11 @@ snapshots:
     transitivePeerDependencies:
       - supports-color
 
-  supertest@7.2.2:
+  supertest@7.2.2(supports-color@7.2.0):
     dependencies:
       cookie-signature: 1.2.2
       methods: 1.1.2
-      superagent: 10.3.0
+      superagent: 10.3.0(supports-color@7.2.0)
     transitivePeerDependencies:
       - supports-color