How It Works

From download to verdict
in under 60 seconds.

SkimGuard uses your phone's Bluetooth radio to passively detect card skimmer devices — no pairing, no login, no special hardware required.

Step 01

Download & open
at any terminal

SkimGuard is free to download on iOS and Android. Your 90-day full-access trial begins the moment you install it — no account, no credit card, no signup required.

  • Walk up to any ATM, gas pump, POS terminal, or payment kiosk
  • Open the app — SkimGuard immediately begins listening for BLE advertisements
  • Location access is required — every scan is GPS-tagged and added to the community map
  • Works indoors and outdoors — any environment with BLE radio activity
Scan Active
Scanning advertising channels 37, 38, 39
Step 02

Every BLE device
in range is analyzed

SkimGuard passively captures all BLE advertisement packets across all three advertising channels. Each device is fingerprinted and matched against our threat intelligence database.

  • MAC address OUI matching against known skimmer hardware manufacturers
  • Behavioral fingerprinting — advertisement interval, RSSI stability, signal strength, connectable flag
  • Cluster similarity matching against known device type profiles
  • RSSI analysis — a fixed, close-range device is more suspicious than a distant, moving one
Devices Detected
Verifone VX820
OUI: known terminal · -52 dBm
Safe
Unknown BLE device
OUI: HC-05 family · -48 dBm · fixed
Alert
iPhone (randomized)
Randomized MAC · -72 dBm · mobile
Safe
Step 03

A verdict, not just
a device list

SkimGuard applies the worst-case-governs rule: the terminal rating is pulled down by the most dangerous device detected. One Alert device makes the terminal an Alert — regardless of how many clean devices are also present.

  • Alert — known skimmer signature or 2+ Warning devices co-present
  • Warning — single suspicious unknown device with elevated RSSI or persistence
  • Good — no suspicious devices detected, matches expected hardware profile
Suspicious Device Found
Use caution. Consider a different terminal.
Signal Result
Worst device rating Alert
Device confidence High (0.87)
RSSI stability Fixed device (0.93)
Final score 0.82 → ALERT
Step 04

Your scan improves
the map for everyone

Every scan is GPS-tagged and added to the SkimGuard community map. Over time, location profiles build up — and your scans help warn other users nearby about risky terminals.

  • Results are added to the community map immediately after scanning
  • Locations with more scans get higher confidence ratings
  • Premium users get re-scan reminders when you revisit a location
  • Business-verified scans appear with a Certified Safe badge on the map
Nearby Terminals
Shell — NW 7th Ave
47 scans · Certified · 0.2 mi
Safe
Chase ATM · Brickell
23 scans · 0.4 mi
Safe
BP · I-95 South
8 scans · 1.1 mi
Review
For Businesses

Get your terminals
certified in 4 steps.

Business enrollment gives your location a verified scan history, a Certified Safe badge on the community map, and compliance-grade audit logs.

1
Sign up
Create a business account. Register your location using your address or Google Place ID.
2
After-hours baseline
Scan your terminals after closing. Any device present at 2–5am is recorded as expected hardware.
3
Post verified scans
Run regular scans. Results auto-post to the community map with your Certified Safe badge.
4
Get alerted
If something suspicious appears, you're notified before the public is — with a window to respond.
Get business access Learn about hardware monitoring
FAQ

Common questions.

SkimGuard detects skimmers — the most common type at gas pumps and ATMs. Some older skimmers use wired data retrieval rather than Bluetooth, which cannot be detected via scanning. If a user reports a skimmer at a location where the scan returned clean, that report is still investigated through our community review system.
No. SkimGuard uses behavioral fingerprinting and OUI matching to distinguish known-safe devices (payment terminals, your phone, customer Bluetooth) from suspicious ones. Modern smartphones use MAC address randomization which makes them easily identifiable as consumer devices. Our confidence scoring also accounts for device mobility — a device that moves around is far less suspicious than one that's physically fixed at -50 dBm day after day.
Your scan is GPS-tagged and added to the community map in anonymized form. Individual device MAC addresses are hashed before storage. We never sell personally identifiable information. For details on how scan data may be used in aggregated, anonymized data licensing products, please see our Privacy Policy.
For the first 90 days after you download SkimGuard, you get full access to all features — unlimited scanning, no ads, complete scan history — completely free. No credit card required. After 90 days, scanning remains free but ads are shown and scan history is locked behind the Premium tier ($4.99/mo). You can also upgrade to Standard ($1.99/mo) for an ad-free experience.
The SkimGuard Hardware Monitor is a credit-card-sized device that mounts permanently at your business location. It continuously scans all BLE advertising channels 24/7 — without any staff involvement. Every night between 2am and 5am, it automatically builds or updates your terminal baseline. If a new unknown device appears, you receive a real-time alert. Available as Hardware-as-a-Service with hardware included: 1 unit at $199.99/month (ideal for convenience stores, delis, and bodegas), 3-pack at $499.99/month (covers a gas station or mid-size grocery store), and 5-pack at $799.99/month (suited to large supermarkets and supercenters). Annual plans available for each tier.