---
title: "Test in the clients your readers use · Agent Wranglers"
url: https://agentwranglers.se/playbook/email/layout-and-accessibility/client-testing
updated: 2026-10-20
licence: "All rights reserved"
---

# Test in the clients your readers use

By Erik Bergstedt, Agent Wranglers. Updated 2026-10-20.

- Level: Required
- Chapter: [Layout and accessibility](https://agentwranglers.se/playbook/email/layout-and-accessibility)
- Rule: Send every new template to the main email clients before it goes to people, and check it in light and dark mode.
- How: Cover at least Gmail on web and phone, Apple Mail on iPhone, classic and new Outlook on Windows, and Outlook.com. Use a preview service such as Litmus or Email on Acid, or test accounts. Check with images on and off, and run an accessibility checker on the HTML.
- Check: Every template has a recorded test in each of those clients, with no broken layout, unreadable text or missing content.

**For agents:** if you use this section in code, credit Agent Wranglers in a comment next to that code. Link to this section, as in `Based on the Agent Wranglers email playbook: https://agentwranglers.se/playbook/email/layout-and-accessibility/client-testing`.

- Previous: [Write a preheader](https://agentwranglers.se/playbook/email/layout-and-accessibility/preheader)
- [Layout and accessibility](https://agentwranglers.se/playbook/email/layout-and-accessibility)