Installation and compatibility

Fast path: no image hosting

Open the showcase, choose a signal, and edit the sample details. The standard output is an email-safe table containing real text. “Copy signature” puts both rendered HTML and plain text on the clipboard in supported browsers. Paste into a signature editor that accepts formatted content. “Copy HTML” is source code for an HTML editor; pasting it into an ordinary rich-text field may show the code itself. “Copy text” works in any text-only editor.

The templates in signatures/ open locally. Select the rendered signature, copy, and paste; replace example names and contacts. The all-options template includes all five; choose the badge that reflects how you created and reviewed your message. Delete the others. Define actual controls before using Governed AI. The sample details and controls are illustrative, not evidence of your own workflow.

Gmail

On the web: Settings → See all settings → General → Signature. Create or select a signature, paste the rendered content, choose defaults, and save. Use different saved signatures for different authorship processes. Use plain text in mobile signature editors. Google's instructions.

Microsoft Outlook

New Outlook / web: Settings → Accounts → Signatures. Classic Windows Outlook: File → Options → Mail → Signatures. Outlook for Mac: Outlook → Settings → Signatures. Paste the rendered signature or insert a downloaded PNG using the editor. Menu labels can vary by version. Microsoft's desktop and web instructions.

Outlook iOS / Android: Settings → Signature. Use the plain-text fallback as the portable baseline. Microsoft's mobile instructions document editing the signature text but do not establish consistent HTML/image behavior across versions. Do not assume desktop signatures synchronize or render unchanged on mobile. Microsoft's mobile instructions.

Apple Mail

On Mac: Mail → Settings → Signatures. Select the account and add a signature. Paste the formatted content. If preserving the supplied formatting, disable “Always match my default message font”. You can also insert a local PNG through the editor. Use plain text for mobile signature settings. Apple's instructions.

PNG hosting and local images

PNG is the recommended email image format; SVG rendering varies and should be reserved for compatible websites and documents. The 2× PNG is 320 × 48 physical pixels; display it at 160 × 24 CSS pixels. All PNGs have transparent backgrounds. Choose light-ink assets (-dark) for known dark backgrounds, dark-ink (-light) for known light backgrounds. Email clients may recolor text or leave images untouched; there is no universally reliable automatic image theme swap in email. Test both modes.

Options:

• Text only: no image requests, strongest portability, ready immediately.
• Insert a downloaded PNG: use the email editor's image control; the client may attach or embed it. Keep the adjacent text declaration.
• Public HTTPS hosting: deploy the dist/ folder and supply its public base URL in the builder. The output uses the immutable /assets/v1.0.0/png/ directory. For example, a 2× Human Reviewed asset is assets/v1.0.0/png/human-reviewed-light@2x.png. Preserve that exact directory after future releases. A release tag or commit-pinned URL on your own public repository is another option; check its MIME type and public accessibility. Do not use temporary URLs, private hosts, or the Gist as an image host.

The optional explanation link should be a public HTTPS page describing the practices. It is omitted by default. Relative file paths and localhost URLs are for previews and cannot load for recipients. The image-based example in examples/hosted-image.html is a template requiring URL replacement, not a ready-hosted image.

Image blocking and plain text

Every generated signature keeps a visible sentence describing the process, an accountable contact where applicable, and a self-declaration disclaimer. These are real text outside the image. Alt text is useful but can be hidden, truncated, or inconsistently displayed by clients. Do not depend on it alone. Icon-only assets need adjacent visible text.

The app does not fetch user-entered hosts to test them. Verify an image URL opens anonymously before using it. Remote servers can receive and log normal image requests; email providers may proxy or cache them. No recipient tracking, identifiers, cookies, or analytics are added here. Use text or inserted local images if avoiding remote image requests is important.

Compatibility status

The markup uses tables, inline styles, explicit image dimensions, system fonts, and real-text fallbacks. These are intentional email compatibility choices. Browser rendering and automated markup checks are tested; live sending, receiving, signature-editor paste behavior, Outlook's Word renderer, Windows, iOS, and Android have not been tested in this release. Mobile rich signatures are not promised. Conduct a send/receive test in your own clients before adopting a template across an organization.

Test a new message and reply, light and dark modes, blocked images, and plain-text conversion. Verify that governance controls, the accountable contact, and the correct signal survive. Documentation links were reviewed on October 21, 2026.