html_mail

Email clients are the most hostile rendering environment in business software: no external stylesheets, wildly inconsistent CSS support, and layouts that fall apart outside a browser. html_mail exists because of that. It subclasses the standard html editor field and changes exactly the things that break email.

Users see the familiar rich text editor. The difference happens when content is read back for saving: the widget walks the edited document, computes the styles the browser actually applied, and writes them into inline style attributes using the conversion helpers that ship next to it. What lands in the database is markup a mail client can render without ever seeing Odoo's stylesheets. That is why an email body authored in Odoo survives Gmail, and why this widget rather than plain html backs mail templates, group messages and recruitment correspondence.

For a business the widget's constraints are features. Every capability it removes, multi column layouts, embedded interactive blocks, attachment generating image drops, is something that would have looked fine in Odoo and broken in your customer's inbox. Guardrails beat guidelines: authors physically cannot produce the layouts that fail.

The practical implication for teams building templates: author inside Odoo, not by pasting from design tools. Content pasted from a web design export arrives with class based styling that only partially survives the inlining pass, which is the root of most "our newsletter looks different in Outlook" tickets. Keep master content in the template, use the editor's own formatting, and test with a real send to a Gmail and an Outlook account before a campaign, not after.

Standard email body field

<field name="body_html" widget="html_mail"/>

Fixed height editing box

<field name="body_html"
       widget="html_mail"
       options="{'height': 400}"/>

Text only email body, media disabled

<field name="reply_body"
       widget="html_mail"
       options="{'allowImage': False, 'allowVideo': False, 'allowFile': False}"/>

Dynamic placeholders on a template model

<field name="body_html"
       widget="html_mail"
       options="{'dynamic_placeholder': True, 'dynamic_placeholder_model_reference_field': 'model_id'}"/>

The 19.0 subclass makes exactly four moves on top of the html field, all visible in getConfig and getEditorContent:

CSS inlining on read back. getEditorContent clones the edited document, temporarily mounts the clone so computed styles resolve, and runs toInline with rules gathered by getCSSRules, cached per editor instance in a WeakMap. Class driven appearance becomes inline styles; markup leaves the field email ready.

Column plugin removed. The editor's plugin list is filtered to drop the column layout plugin, because multi column structures are the classic Outlook casualty.

Attachment free image drops. dropImageAsAttachment is off, so dragging an image into the body does not mint an ir.attachment the way it does in the standard html field.

Safe link defaults. Links created in the editor get target="_blank" and rel="noreferrer noopener" automatically.

Everything else, toolbars, powerbox, history, is the shared html editor. That inheritance is also the risk surface: options added to the base field arrive here untested for email fitness, which is why the option table's descriptions note where mail overrides them.

Odoo 20 is expected at Odoo Experience in Brussels, 24 to 26 September 2026. Everything below is read from the public development branch, which can shift until feature freeze, and this page is re-verified against the shipped build.

Dynamic placeholders gain a permission system. The branch adds a field filter wired to the allowed_qweb_expressions service: users without the mail template editor group can only insert placeholder paths from an approved whitelist, and one2many, many2many, boolean and non searchable fields are excluded outright. Template injection through placeholder pickers gets materially harder.

Datetime placeholders localize themselves. Inserting a datetime field now generates a format_datetime expression carrying the recipient partner's timezone when the model exposes one, with the label as fallback text. Timestamps in emails stop defaulting to server time.

One new option appears: no_move_node_plugin. It disables the editor's block drag handles inside the mail variant.

Teams with heavy template customization should budget a re-test of placeholder driven templates during the upgrade; our Odoo migration service includes exactly that pass.