The Google Pixel modem zero-click flaw patched this month (CVE-2026-58704) reminded everyone that the cellular chip in a phone is a computer in its own right, running its own firmware, and mostly invisible to the operating system. If you own a Pixel, apply the 2026-09-05 patch first. Then, if you want to see what the modem is actually doing, install one of the apps below.
These are the best apps for Android modem diagnostics in 2026. We tested them on Pixel 9, Pixel 11, and Galaxy S26 Ultra hardware, and picked the seven that surface real signal, cell tower, and radio-frequency information without pretending to be antivirus.
What matters in a modem diagnostic app
- Reads the phone’s telephony APIs correctly. Some apps guess and get band assignments wrong.
- Works without root on modern Android (14, 15, 16). Root-only tools have limited audience.
- Shows the raw signal metrics that matter: RSRP, RSRQ, SINR for LTE; SS-RSRP, SS-RSRQ for 5G.
- Maps cell towers so you can see which tower you are actually attached to.
- Does not phone home. Modem data is sensitive; do not send it to a stranger’s server.
Quick comparison
| App | Best for | Platforms | Free plan | Starting price | Rating |
|---|---|---|---|---|---|
| Network Cell Info Lite | Everyday cell metrics | Android | Yes | Around $5 for Pro | 4.5/5 |
| NetMonster | Multi-carrier mapping | Android | Yes | Optional donation | 4.7/5 |
| Cellular-Z | Comprehensive readouts | Android | Yes | $0 | 4.4/5 |
| SignalCheck Pro | Enthusiast dashboards | Android | 7-day trial | Around $6 one-time | 4.6/5 |
| Wigle WiFi Wardriving | WiFi and cell mapping | Android | Yes | $0 | 4.3/5 |
| SnoopSnitch | Cellular attack detection | Android | Yes | $0 | 4.4/5 |
| Speedtest by Ookla | Standard throughput tests | Android | Yes | Ad-free ~$5/mo | 4.5/5 |
The apps
1. Network Cell Info Lite, best for everyday cell metrics
Network Cell Info Lite is the app most enthusiasts install first. Clean dashboards, dual-SIM support, LTE and 5G metrics, and cell tower coordinates on a map. Free version covers the basics; the Pro upgrade adds signal logging and band-specific graphs.
Where it falls short: the free version’s ad load is heavy. Pro removes ads.
Pricing:
- Free: full base app with ads.
- Paid: around $5 for Pro (ad-free, logging).
Platforms: Android.
Download: Google Play · Publisher site
Bottom line: the app most people should try first.
2. NetMonster, best for multi-carrier mapping
NetMonster is the open-source Android alternative to European multi-SIM diagnostic tools. It shows every attached cell, historical signal, and neighbor cells on one panel. Its heatmap view is uniquely useful for anyone testing home coverage.
Where it falls short: the UI density scares off first-time users. The learning curve is real for the map view.
Pricing:
- Free: full app (open source).
- Paid: optional donation.
Platforms: Android.
Download: Google Play · GitHub · Publisher site
Bottom line: the open-source tool for anyone who wants both SIMs surfaced.
3. Cellular-Z, best for comprehensive readouts
Cellular-Z was built by a Chinese developer and remains one of the most complete readouts on Android. Bands, physical cell IDs, TAC codes, MCC and MNC, RSRP and RSRQ, band count, and provider details are all on one screen.
Where it falls short: the developer’s website is Chinese-language. Support outside China is community-driven.
Pricing:
- Free: full app.
- Paid: none.
Platforms: Android.
Download: Google Play · APKMirror mirror
Bottom line: the “one screen has everything” diagnostic app.
4. SignalCheck Pro, best for enthusiast dashboards
SignalCheck Pro is the app the North American cellular enthusiast community rallied around. Dashboard-heavy, real-time signal graphs, connection state logging, and a “cell towers I have seen” history. The developer publishes carrier-band-specific tables for the US big three.
Where it falls short: one-time paid app. There is a free “Lite” variant, but the Pro tier is where the useful features live.
Pricing:
- Free: 7-day trial and free Lite variant.
- Paid: around $6 one-time for Pro.
Platforms: Android.
Download: Google Play · Publisher site
Bottom line: the paid app that hobbyists happily buy.
5. Wigle WiFi Wardriving, best for WiFi and cell mapping
Wigle logs every WiFi and cell tower you pass and uploads them (opt-in) to the community Wigle database. Useful for anyone mapping coverage in an area, cross-referencing carrier deployments, or hunting rogue cells.
Where it falls short: the “wardriving” branding aside, the uploaded data goes to a public database. Opt out of upload if privacy matters to you.
Pricing:
- Free: full app.
- Paid: none.
Platforms: Android.
Download: Google Play · Publisher site
Bottom line: the community-database entry point.
6. SnoopSnitch, best for cellular attack detection
SnoopSnitch is the app that started because researchers noticed IMSI catchers were more common than the industry admitted. On rooted Android with a compatible Qualcomm modem, it detects suspicious cell activity: SS7 attacks, silent SMS probes, and downgrade attempts.
Where it falls short: requires root and a specific Qualcomm modem chipset. Pixel and Samsung Exynos devices are largely out of scope.
Pricing:
- Free: full app (open source).
- Paid: none.
Platforms: Android (rooted, Qualcomm modem).
Download: Google Play · F-Droid · Publisher site
Bottom line: niche, but the only serious cellular attack detector on Android.
7. Speedtest by Ookla, best for standard throughput
Speedtest is the benchmark every carrier and reviewer cites. Latency, download, upload, and jitter across a known global server network. Its download and upload numbers are the numbers your carrier’s support desk will ask for.
Where it falls short: it measures throughput, not signal quality. A phone with a great Speedtest score can still have a poor RSRP if you are attached to a nearby tower with lots of headroom.
Pricing:
- Free: base app with ads.
- Paid: around $5/mo for ad-free.
Platforms: Android, iOS, Windows, macOS.
Download: Google Play · Publisher site
Bottom line: the throughput test everyone standardizes on.
How to pick the right one
- Install Network Cell Info Lite first. It is the friendliest overview.
- Add NetMonster if you use two SIMs.
- Install Cellular-Z if you want raw readouts on one screen.
- Buy SignalCheck Pro if you are seriously benchmarking coverage across multiple locations.
- Add Speedtest by Ookla for throughput. Everyone else is measuring signal quality; this measures speed.
- Use SnoopSnitch only if you can root your device and have a compatible chipset.
FAQ
Do these apps require root? Only SnoopSnitch needs root and a Qualcomm modem. Every other app on this list works on stock Android without root.
Can these apps tell me if I am being spied on? SnoopSnitch is the closest, and only on rooted Android with a compatible chipset. For most users, “spied on via cellular” is a low probability compared to the risks of a compromised app.
Which app is best for finding out which band I am on? Cellular-Z and NetMonster both show the current band and neighbor bands on one screen.
Are any of these apps open source? NetMonster and SnoopSnitch are open source. Others are proprietary but do not require sensitive permissions.
Do these work on the Pixel 11 and Galaxy S26? Yes. Both devices expose the modern telephony APIs these apps rely on. On the S26 you may need to grant a phone permission on first launch.
