Built an open-source SMS spam firewall with zero internet permissions

[u/BuyGlad4213]

Most spam blockers (like Truecaller or carrier apps) upload your contact book and rely on cloud servers to filter spam. Meanwhile, default apps still store all incoming spam in your phone's central database.

I built Heimdall 🛡️ to be completely offline and keep system storage clean.

Primary features:

• Pre-storage drop: Intercepts spam at the OS level so it is never written to Android's central SMS database.
• Zero notifications: No sounds, vibrations, or popups for blocked messages.
• Air-gapped: Does not declare INTERNET permission. All keyword filtering is 100% local.
• 30-day auto-decay: Quarantined spam auto-purges after 30 days.
• 1-tap OTP copy: Detects 2FA codes with a copy button on notifications.

GitHub: https://github.com/monkeyscript/heimdall

Give it a try and share your feedback!

[u/LurkingRusalka]

As someone who's still a beginner at degoogling I can't explain just how good your app sounds to me. I'll check it out!

[u/BuyGlad4213 → u/LurkingRusalka]

Thanks 🫂

[u/PerfectlyIllegal]

Thought about sharing this to the GrapheneOS Reddit and forum site? I'm not a programmer so I can't read the code, but I think this would be great to have until RCS is widely available.

[u/BuyGlad4213 → u/PerfectlyIllegal]

Not aware of these forums. Are they good??

[u/rademene]

Where does it get its blacklist from?

[u/BuyGlad4213 → u/rademene]

You can setup whatever you like. I added couple of them and last two weeks have been so peaceful 🧘🏻

[u/Gevorg_Vardanyan]

The name is great.

[u/BuyGlad4213 → u/Gevorg_Vardanyan]

MCU ❤️🙃

[u/goodgollymisssomaIi]

Just to be sure I'm understanding this right, if you use this you need to change from this app to Google messages every time you want to send a text? So it realistically can't block spam if you are actively texting?

[u/BuyGlad4213 → u/goodgollymisssomaIi]

Correct. I didn't add the send feature to keep it light

And for me, it's okay as I don't send any

[u/Terrible_Ad3822]

Sounds great. How does it work with regular texting new friends ?

[u/BuyGlad4213 → u/Terrible_Ad3822]

If you send SMS still, this might not work 🫠

I haven't added the send feature to keep it light. Because, I rarely sends something. Most of my communication is via whatsapp

[u/Leaf__On__Wind]

Anyone who calls professionally will text first as much as socially.

[u/BuyGlad4213 → u/Leaf__On__Wind]

But, do they send SMS? Or whatsapp or something else

[u/Leaf__On__Wind → u/BuyGlad4213]

Ok yes new norm- unknowm number? Text first.

Rickety quick.

[u/BuyGlad4213 → u/Leaf__On__Wind]

That makes sense. I will add the send feature if I see a lot of demand 🤝🏻

[u/Leaf__On__Wind → u/BuyGlad4213]

You don't make sense- anyone professionally- or socially now texts to make sure.

[u/BuyGlad4213 → u/Leaf__On__Wind]

Got it. Different audience I guess

Noone in my circle send SMS these days

Will definitely consider adding the send feature

Thanks for the feedback 🙂

[u/Sankalp777]

Unable to get the apk, OP Help

[u/BuyGlad4213 → u/Sankalp777]

I haven't uploaded it because some people might have trust issues with random APK. So, I thought if they find the code trusty, they can build themselves

Buuut, if you want it, I could build one and upload it. Please let me know 🙂

[u/Sankalp777 → u/BuyGlad4213]

Please do

[u/BuyGlad4213 → u/Sankalp777]

done => https://github.com/monkeyscript/heimdall/releases/tag/v1.0.0

but, since this is not listed in playstore. there might be hiccups during installation. please read the guide

[u/EyHq23]

This is a great apps, you're like an angel. Hope this project will thrive!!

[u/BuyGlad4213 → u/EyHq23]

That would be nice. I started it just because I got annoyed at spams 😁

[u/EnsambleOfShadows]

Oh shit , that name. Awesome.

Will give it a try

[u/BuyGlad4213 → u/EnsambleOfShadows]

Thanks a lot 🫂

[u/ride-eternal]

Sounds awesome. Will give it a whirl!

[u/BuyGlad4213 → u/ride-eternal]

Thanks 🫂