Google Messages extension
A Chrome extension that sends a Mersal contact group as SMS from your own phone number through Google Messages for web, at a controlled pace with hourly and daily caps.
This extension solves one specific problem: you have a list in Mersal and you want to send it as SMS from your own number, with no provider and no per-message fee. The extension opens Google Messages for web — already paired with your phone — and drives the sending from there, so messages leave on your SIM and appear on your handset as if you typed them.
What you need
Chrome, an Android phone paired with Google Messages for web by QR, and a Mersal account with a contact group. You do not need an SMS gateway or message credit.
Installing and running it
Download the extension
From the Updates Hub. The build published there is always the current one, and the extension tells you itself when an update ships.
Sign in with your Mersal account
From the extension icon, press Sign in via mersal.it. You never type a password inside the extension — you are taken to the site and returned.
Open Google Messages for web
And pair it with your phone by QR if it is not paired already.
Use the Mersal panel
A green Mersal panel appears at the bottom of the Google Messages page: pick the group, write the message, and start.
Pace and limits
The extension offers three sending paces:
- Slowest and safest — for new numbers, or if you are worried about a restriction.
- Balanced — the default: a reasonable pace with good protection.
- Fastest — for an old, trusted number only; the risk of a restriction is higher.
On top of that it respects an hourly cap and a daily cap: on reaching the hourly limit it waits, and on reaching the daily limit it stops and continues the next day.
The limits are the protection, not an obstacle
Carriers restrict numbers that send at an inhuman rate. The paces and caps exist for exactly that reason, and pushing past them risks your own SIM.
Wording variants and variables
A message can carry variables from the contact (their name, for example) and can be written in several wordings the system rotates between — which is what makes the messages read as human-written rather than generated from one template.
The log in Mersal
Every message the extension sends is recorded in your Mersal reports, so you follow the results in the same place as every other channel. These messages do not consume message credit, because they left on your SIM rather than through a gateway.
Troubleshooting
The green panel does not appear
Check you are on messages.google.com/web and the extension is enabled, then reload the page. The Scan page button inside the panel re-detects the interface elements.
Message: the send button did not activate
Google has most likely changed something in their interface. Update the extension to the latest build from the Updates Hub; fixes arrive from there.
A number was skipped with 'the open conversation is for a different number'
That is a deliberate safeguard: the extension verifies the open thread belongs to the right number before sending, and skips rather than message the wrong person.