An SMS form uses the sms URI scheme to hand a recipient and message body to a compatible device. The messaging app should show the draft and require the visitor to confirm sending.
Design for a short mobile interaction
SMS works best for brief enquiries. Ask for only the information needed to identify and answer the request, and keep the message introduction compact enough to review on a phone.
Use an international destination
Enter the destination owner's number in international format. FormToInbox removes visual separators and preserves a leading plus sign when generating the SMS URI. The number remains visible in the exported code.
Build the SMS URI safely
Encode the message body before adding it to the URI. Activating the link should open a composer; it should not silently send a message.
const number = '+15551234567';
const message = ['New website enquiry', 'Name: ' + name, 'Topic: ' + topic].join('\n');
window.location.href = 'sms:' + number + '?body=' + encodeURIComponent(message);Test costs and compatibility
Test iOS, Android and any desktop environment you support because handling varies by browser and installed apps. Tell visitors that carrier charges may apply and retain a non-SMS contact option.
Frequently asked questions
Is the SMS sent automatically?
No. The generated link opens a draft and the visitor confirms whether to send it.
Will an SMS form work on desktop?
Only when the device and browser have a compatible handler. Treat mobile as the primary case and provide a fallback.
Can an SMS form store submissions?
No. The client-side handoff does not create a FormToInbox record or hosted inbox entry.
Primary sources
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