sms_widget

Anywhere Odoo lets you write a text message, the Send SMS action on a contact, the body of an SMS Marketing campaign, the composer behind automated SMS, the text box is sms_widget. It looks like a normal multiline text field with an emoji picker, but below it sits a line of arithmetic that updates on every keystroke: character count and number of SMS segments.

That arithmetic is the widget's whole reason to exist. SMS is billed per segment, and segment size depends on encoding. The widget classifies your message with one regex: if every character belongs to the GSM-7 charset (the 7-bit alphabet from the GSM 03.38 standard, which covers basic Latin, digits and a set of accented letters), the message packs 160 characters into one SMS and 153 into each segment of a longer one. A single character outside that set, a curly apostrophe pasted from Word, an emoji, a script like Devanagari, silently switches the entire message to Unicode: 70 characters per single SMS, 67 per segment.

It is built on top of the emoji text field, which itself extends the standard text widget, so everything you know about multiline text fields applies here too.

For anyone running SMS campaigns, this widget is the difference between predictable and surprising invoices.

The one-character cliff is real money. A 150-character message in GSM-7 is one segment. Paste in a single smart quote and the same message becomes Unicode: now it is three segments, three times the credits, multiplied by every recipient in the campaign. The counter makes that visible before you hit send, but only if your team knows to watch it. We train marketing teams to draft SMS copy directly in Odoo rather than pasting from word processors, precisely because of this.

The counter also protects deliverability. The blur check that rejects whitespace-only messages, and the SMS Marketing additions that count the opt-out link and tracker URLs, exist so the number you see matches what the gateway actually bills.

How the SMS composer uses it

<field name="body" widget="sms_widget" default_focus="1"/>

On your own model's message field

<field name="reminder_message" widget="sms_widget" placeholder="Text sent to the customer..."/>

The field should be a Text field; the counter and emoji picker come for free. The sms module must be installed.

Segment math cheat sheet

GSM-7:    1-160 chars = 1 SMS, then ceil(n / 153) segments
Unicode:  1-70 chars  = 1 SMS, then ceil(n / 67) segments
Line breaks count as 2 characters. One non GSM-7 char = whole message Unicode.

Three behaviors from the source are worth pinning down precisely.

Line breaks are counted twice. The character count is content.length plus one extra for every newline. That mirrors the GSM standard, where a line feed in the extended table costs an escape character, and it is why a heavily formatted message runs out of room faster than its visible length suggests.

The whitespace guard runs on blur, not on save. Leaving the field with a message that contains only spaces or newlines pops a danger notification, "must include at least one non-whitespace character", and trims the value to empty. The record updates on every keystroke before that, so the guard is the last word.

SMS Marketing rewrites the message before counting it. The mass_mailing_sms module patches the widget for mailing.mailing records: every URL in the body is replaced by a placeholder the length of a link tracker URL, and if the mailing has the opt-out option enabled, the unsubscribe link's length is added on top. The counter then annotates itself, "(including link trackers and opt-out link)", so the segment estimate matches what actually leaves the gateway. Both placeholder lengths are fetched from the server per mailing.

Odoo 20 is expected at Odoo Experience in Brussels, 24 to 26 September 2026. The notes below are read from the public development branch and are not final until release.

Nothing changes: the widget's source file on master is byte-identical to Odoo 19, including the encoding regex, the segment limits and the SMS Marketing patch points. Views and customizations should carry over untouched. We re-verify against the shipped release.