Receive SMS missed while device was off

I’m new to voip. I got a account and was able to make calls and sms to and from my (Linux) computer and phone. However, when I tested sending texts to my computer while the computer was off, the computer never got the texts even when the computer was turned back on. I don’t want to have to have my computer on all the time.

I do have a VPS where I could install Asterisk or some other server software if it helped and if the setup work was reasonable. has options for sending SMS to email (but then you can’t see the message flow from a single sender as easily) or HTTP GET request (but I don’t want to write an instant messaging web application). I asked their support about texting while the device is off and they said “You can receive SMS through a softphone app, and they will be available only 1 hour after being sent and the app not being registered. There’s no specific app to do what you mention”

Any suggestions? Is this a limitation of SIP - would AIX behave differently? Is this a limitation of - do other PSTN-to-SIP providers push missed messages out when the device comes back online/registers/whatever? Would a PBX on my VPS provide a solution with a reasonable amount of setup work? Is there an analog of email IMAP/POP for SMS messages - where the server stores messages until the client pulls them down or syncs them? From what I remember looking into OpenPhone it seemed like it would work for me, but I would prefer an open source or at least industry standard not-locked-into-one-provider solution.


It’s a limitation of the provider, SMS over GSM is also pushed to the phone, but the SMS centre holds onto messages for a reasonable time.

It’s a limitation of the provider, SMS over GSM is also pushed to the phone, but the SMS centre holds onto messages for a reasonable time.


so switching to Callcentric/Flowroute/Anveo or other may solve the problem? Or do they all have this short-hold-of-messages behavior?

If it’s just that the provider isn’t holding onto the messages for very long, would a PBX solve the issue - could you have a PBX that held onto the messages for a longer time - say a couple days or a week?

I wonder if there is something more going on than just the message holding time. It seems like the turn-off-computer-send-text-turn-back-on process took less than an hour - unless actually holds for less than an hour…? Not sure. I can retest if useful.

I don’t know. It depends on how important people who are offline most of the time are for their business model How much money do they make from each message? My guess is that none will.

My guess is that there isn’t much of demand for this feature. I don’t think FreePBX offers it. Asterisk is a PBX construction toolkit, so won’t even deliver them without some specific configuration. You could configure it, probably when combined with other software, like cron jobs, to implement it.

Did you unregister before going offline. Maybe they don’t handle delivery failures well.

None of this has to do with SIP. is offering ways for you to get your SMS/MMS messages. You can use their portal, email notices or you can use a RESTful API call to pull the messages from their server. None of that is SIP. They do not send SMS over SIP and if they did it would be over SIMPLE so it can be sent via your SIP connection.

None of what they do for SMS/MMS is related to a device being online or registered. It’s a completely different process. If you don’t want to use their available solutions or write a RESTful API call (which all major providers require) then you’re not going to get far with SMS/MMS.

Maybe the client didn’t unregister. I recently tested explicitly going offline in Jami (without turning off the computer) and when I came back online I did get the texts that were sent interim. Maybe before it didn’t unregister when I shut down. Seems like a fault on both sides - the server shouldn’t throw away messages right away because of failed delivery, but also the client should unregister when I shut down the computer.

What would be the order of magnitude of this undertaking for someone familiar with Linux but not familiar with Asterisk? A day or two installing a package, configuring files, and maybe writing a script? Or is there a large learning curve barrier?

I already got texting working with Jami on the computer, separate from the portal, email, or writing an API. I just missed texts when the computer was off. Does Jami have pre-written API calls specific to, or is the API standardized across providers? Otherwise, how can it not be SIP?

Edit: just tested with MMS, and it doesn’t seem to work on Jami, but I can see it in the portal - is this what you’re talking about? SMS over SIP, but MMS must be over API?

So this is what I ended up doing if it helps anyone else.

I made a sort of email/text gateway on the VPS i’ve been using. I configured to send me URL requests when new messages come in. Then, on my VPS I have an HTTP server that responds by making an API call to in case there was a picture attachment that does’t send with the webhook. The HTTP server then packages the text (with picture if there is one) into an email and sends it to me. I also have an SMTP server that receives emails, and based on the sender and receipient of the email ( converts to a text sent through the API.

Now since my mail server provider and my newly created gateway are both always online, I can turn off my devices at home for as long as I want without missing any texts or worrying about registrations.

I also found an email client “Delta Chat” that will access IMAP and provides a chat feel to emails so texting over email looks kind of like a normal messenger app.

No group chats though since doesn’t support that. Twilio might, but I’d have to figure out their API and deal with the switch so I’m calling it good enough for now.

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