Location provider for UnifiedNlp and microG using only local data.
About this app
The backend passively monitors the GPS and scans for nearby WiFis and mobile cells/towers. From this a database of emitter locations is created. When UnifiedNlp / microG request a location from Local NLP Backend, a scan for nearby emitter is initiated and a location determined based on the scan results.
Local NLP Backend is a fork of the Déjà Vu NLP Backend with some improvements and a crude UI for configuration and importing / exporting data, including cell lists from MLS or OpenCelliD.
This backend uses no network data. All data acquired by the phone stays on the phone, though it may be exported manually.
How to use:
Local NLP Backend can be used like Déjà Vu: just enable the backend and let it build up the database by frequently having GPS enabled, e.g. using a map app. If you have a Déjà Vu database (you'll need root privileged to extract it), it can be imported in Local NLP Backend. Further import options are databases exported by Local NLP Backend, and cell csv files from MLS or OpenCelliD. Note that the local database needs to be filled, either using GPS or by importing data, before Local NLP Backend can provide locations!
In order to speed up building the database, LocalNLP has an optional active mode that enabled GPS when there is no known emitter nearby (low setting) or when any unknown emitter is found (aggressive setting).
Note that microG has stopped supporting UnifiedNlp backends with 0.2.28. If you still want to use this backend (or others), you need to use older microG versions. This can only be recommended if you use microG for location only. Personally I use 0.2.10, as with later versions location backends stop providing locations after some time.
Licensed under GPL-3.0-or-later.
What's New in v1.2.15
Imported from the F-Droid repository index.
Version history
Aug 1, 2025 · 1.1 MB · Android API 18–34 · code 43
Imported from the F-Droid repository index.
SHA-256 61c52b9502b959fb4324ffa40063de33cd25f475c15cc202406017ff7d5c03f1
Jan 24, 2025 · 1 MB · Android API 18–34 · code 42
Imported from the F-Droid repository index.
SHA-256 01f7b36b683989d95540caa03446ecd14b5793278c16718e71a44778de42ef90
Jan 2, 2025 · 1 MB · Android API 18–34 · code 41
Imported from the F-Droid repository index.
SHA-256 43c892e61864a1ac5a27fda0b20560ea347f2e893bdc9ecf1973a54b261800de
Will it run on your device?
73%
- Runs on a broad range of modern Android versions.
- ABI coverage is focused on newer 64-bit devices.
Installation Guide
Open Settings on your Android device
Go to Security → Unknown sources (or Install unknown apps)
Enable "Allow from this source" for your browser or file manager
Open the downloaded APK file from your Downloads folder
Tap "Install" and wait for installation to complete
Launch the app from your home screen
Make sure to re-enable Unknown Sources restrictions after installation for security.
How to install this safely
How to verify the file you downloaded
Before you install anything, confirm the file is the one described here. On a computer, run shasum -a 256 your-download.apk (macOS or Linux) or certutil -hashfile your-download.apk SHA256 (Windows), then compare the output character-for-character with the SHA-256 on this page. If a single character differs, the file is not the build we recorded — delete it.
What the signing certificate proves
Every Android app is signed with a private key that only its developer holds. The fingerprint on this page is a hash of the matching public certificate, and it proves continuity rather than identity: it tells you a build came from whoever signed the earlier ones. Android enforces this at install time — if a package claiming to be helium314.localbackend is signed with a different key, the system will refuse to install it over your existing copy. A fingerprint that changes between releases is worth pausing on, because a repackaged app that has been modified by someone else cannot keep the original signature.
How to roll back to an earlier version
If the current release misbehaves, 1.2.14 is the last build before it. Android will not install an older version code over a newer one, so you must uninstall Local NLP Backend first — which clears its local data unless you have a backup. Reinstall the older APK only if its signing fingerprint matches the build you already trust, and check the API range: an older release may target an Android version your device has moved past.
Why we list sources instead of hosting everything
The official store channel is almost always the right choice: it updates automatically and carries the publisher's own distribution guarantees. A direct APK is useful when a device has no store access, when a rollout has not reached your region, or when you need a specific version — and only when the publisher has authorized that copy. APKBrowse does not list pirated, cracked, or unauthorized rebuilds of Local NLP Backend, and a listing is removed when the evidence for it stops holding up.
Get Local NLP Backend
Every source we list for helium314.localbackend is legality-reviewed. Pirated or cracked builds are never offered.
Other sources
F-Droid listing
officialF-Droid builds this app from source and signs it. This is its official listing, with older builds and full release notes.
Source code
verified publisherThe upstream repository this build is compiled from.
We check legality and signature continuity, but device behaviour still varies. Install at your own discretion.
App Information
Security Verification
We record provenance; we do not run malware scans. Verify the hash yourself before installing.
SHA-256 Hash
61c52b9502b959fb4324ffa40063de33cd25f475c15cc202406017ff7d5c03f1
Signing certificate
ad64e10282ef438f23a91661582aa713fc478411b78a772cb5c0b39e769100eb
Permissions Required
Previous Versions
The signing certificate fingerprint for this release is on record, so a build that does not match it did not come from this publisher.
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