> ## Documentation Index
> Fetch the complete documentation index at: https://docs.lekalao.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Preview and checks

> See the e-mail as your readers will, and fix it before sending.

## The preview

The preview on the right of the editor is rendered by the sending engine itself, with sample values (Ada Lovelace, [ada@example.com](mailto:ada@example.com)). It refreshes half a second after the last keystroke.

| Button                   | Effect                                                                                                                                      |
| ------------------------ | ------------------------------------------------------------------------------------------------------------------------------------------- |
| **Phone** / **Computer** | The width of a phone (390 px) or the full width.                                                                                            |
| **Dark** / **Light**     | Acts like a mailbox in dark mode, which inverts the parts with no explicit colour: the best way to spot dark text on a now-dark background. |
| **HTML** / **Text**      | The e-mail, or the text version built from it.                                                                                              |

When the content cannot be rendered (invalid MJML, a damaged block document), the preview shows the error instead of the e-mail.

## Check the links

**Check the links** calls every link in the content and shows its response code. A link in error (404, 500, unreachable) appears in red. Links to internal or private addresses are not called.

## Check for readers

**Check for readers** reads the rendered e-mail back and points out what gets in the way. They are remarks, never a block: each is marked **Problem** or **Worth a look**.

| Remark                                        | Why it matters                                                               |
| --------------------------------------------- | ---------------------------------------------------------------------------- |
| Images without a description                  | A screen reader, or a mailbox that blocks images, shows nothing.             |
| An e-mail that is almost all images           | Spam filters distrust it, and the e-mail looks empty with images blocked.    |
| Links that say nothing ("click here", "here") | Out of context, a screen reader announces them with no idea where they lead. |
| Text that is too small                        | Unreadable on a phone.                                                       |
| Not enough contrast                           | Text and background too close in brightness (the WCAG ratio).                |
| An e-mail over 100 kB                         | Gmail cuts the end off behind a "View entire message" link.                  |
| No text version                               | Some mailboxes and some filters ask for one.                                 |

"Nothing in the way. This e-mail reads well." means all is well.

## Send a test

**Send a test**: up to five addresses separated by commas. The e-mail goes out through the campaign's provider, with the subject prefixed "\[Test]" and sample values. In an A/B test, the version on screen is the one that goes. No test is counted in the statistics.

<Tip>
  Send yourself a test on **Gmail** and on **Outlook** at least: they are the
  two that stray furthest from the preview, especially with hand-written
  HTML.
</Tip>