diff --git a/app/app.json b/app/app.json
index 600dbd53ec..8d0077d05e 100644
--- a/app/app.json
+++ b/app/app.json
@@ -13,6 +13,7 @@
     "electron-context-menu": "^0.4.0",
     "electron-squirrel-startup": "^1.0.0",
     "httpsnippet": "git@github.com:gschier/httpsnippet.git#39d2fb0449f33711e5cc71a4d42b0e5b808426b4",
+    "json-lint": "^0.1.0",
     "jsonpath-plus": "^0.15.0",
     "nedb": "^1.8.0",
     "node-localstorage": "^1.3.0",
diff --git a/app/lib/__tests__/render.test.js b/app/lib/__tests__/render.test.js
index 144744ccc5..f30a413011 100644
--- a/app/lib/__tests__/render.test.js
+++ b/app/lib/__tests__/render.test.js
@@ -9,6 +9,16 @@ describe('render()', () => {
     expect(rendered).toBe('Hello World!');
   });
 
+  it('renders custom tag: uuid', () => {
+    const rendered = render.render('Hello {% uuid %}!');
+    expect(rendered).toBe('Hello b5c2f089-2c0c-46b6-a6f1-8d5b86cbc603!');
+  });
+
+  it('renders custom tag: timestamp', () => {
+    const rendered = render.render('Hello {% timestamp %}!');
+    expect(rendered).toMatch(/Hello \d{13}!/);
+  });
+
   it('fails on invalid template', () => {
     const fn = () => render.render('Hello {{ msg }!', {msg: 'World'});
     expect(fn).toThrowError('expected variable end');
diff --git a/app/lib/export/curl.js b/app/lib/export/curl.js
index 0e85b32252..608cc61aab 100644
--- a/app/lib/export/curl.js
+++ b/app/lib/export/curl.js
@@ -1,11 +1,5 @@
 'use strict';
 
-import render from '../render';
-import * as querystring from '../querystring';
-import * as db from '../../database';
-import {DEBOUNCE_MILLIS, METHOD_GET} from '../constants';
-import {getRenderedRequest} from '../render';
-
 const FLAGS = [
   'cacert', 'capath', 'E', 'cert', 'cert-type', 'ciphers', 'K', 'config',
   'connect-timeout', 'C', 'continue-at', 'b',
diff --git a/app/lib/render.js b/app/lib/render.js
index dbb69fe5d3..d5597af430 100644
--- a/app/lib/render.js
+++ b/app/lib/render.js
@@ -1,16 +1,59 @@
 import nunjucks from 'nunjucks';
 import traverse from 'traverse';
+import uuid from 'node-uuid';
 import * as db from '../database';
 import {TYPE_WORKSPACE} from '../database/index';
 import {getBasicAuthHeader, hasAuthHeader, setDefaultProtocol} from './util';
 
-nunjucks.configure({
+const nunjucksEnvironment = nunjucks.configure({
   autoescape: false
 });
 
+class NoArgsExtension {
+  parse (parser, nodes, lexer) {
+    const args = parser.parseSignature(null, true);
+    parser.skip(lexer.TOKEN_BLOCK_END);
+    return new nodes.CallExtension(this, 'run', args);
+  }
+}
+
+class ArgsExtension {
+  parse (parser, nodes, lexer) {
+    const tok = parser.nextToken();
+    const args = parser.parseSignature(null, true);
+    parser.advanceAfterBlockEnd(tok.value);
+    return new nodes.CallExtension(this, 'run', args);
+  }
+}
+
+class TimestampExtension extends NoArgsExtension {
+  constructor () {
+    super();
+    this.tags = ['timestamp'];
+  }
+
+  run (context) {
+    return Date.now();
+  }
+}
+
+class UuidExtension extends NoArgsExtension {
+  constructor () {
+    super();
+    this.tags = ['uuid'];
+  }
+
+  run (context) {
+    return uuid.v4();
+  }
+}
+
+nunjucksEnvironment.addExtension('uuid', new UuidExtension());
+nunjucksEnvironment.addExtension('timestamp', new TimestampExtension());
+
 export function render (template, context = {}) {
   try {
-    return nunjucks.renderString(template, context);
+    return nunjucksEnvironment.renderString(template, context);
   } catch (e) {
     throw new Error(e.message.replace(/\(unknown path\)\s*/, ''));
   }
diff --git a/package.json b/package.json
index bdedf2849b..d4f697b870 100644
--- a/package.json
+++ b/package.json
@@ -63,7 +63,6 @@
     "httpsnippet": "git@github.com:gschier/httpsnippet.git#39d2fb0449f33711e5cc71a4d42b0e5b808426b4",
     "json-lint": "^0.1.0",
     "jsonpath-plus": "^0.15.0",
-    "jsonschema": "^1.1.0",
     "mousetrap": "^1.6.0",
     "nedb": "^1.8.0",
     "node-localstorage": "^1.3.0",
@@ -82,7 +81,8 @@
     "tough-cookie": "^2.3.1",
     "traverse": "^0.6.6",
     "xml2js": "^0.4.17",
-    "xml2js-xpath": "^0.7.0"
+    "xml2js-xpath": "^0.7.0",
+    "node-uuid": "latest"
   },
   "devDependencies": {
     "babel-cli": "^6.11.4",