Synapse: Device Check
Test Phones to Buy or Sell
Only for iPhone
Free · In‑App Purchases · Designed for iPhone. Not verified for macOS.
iPhone
Buying or selling a used iPhone? Know what works before money changes hands.
Synapse helps you test key iPhone hardware — including cameras, speakers, microphones, sensors, buttons, connectivity, and biometrics — then creates a clear pass/fail device report you can share with a buyer, seller, repair shop, or resale listing.
QUICK CHECK — FREE
Run a basic test in minutes. No purchase required.
Tests include:
• Display
• Touchscreen
• Rear camera
• Wi-Fi
• Bluetooth
FULL DIAGNOSTIC
Unlock the complete hardware test suite and generate a shareable device report.
Full Diagnostic includes:
• Front camera and flashlight
• Video recording
• Microphones and speakers
• Proximity sensor
• Motion sensors
• Screen rotation
• Face ID or Touch ID sensor check
• Vibration motor
• Volume, lock, and mute buttons
• GPS / location accuracy
• System integrity indicators
• Shareable pass/fail report with device details
DEVICE CHECKS
Purchase Device Checks in the app and save them to your account.
Available options:
• Single Device Check
• 3 Device Checks
• 10 Device Checks
Sign in with Apple or email to save your purchased Device Checks, view your remaining checks, and use them on this device or another signed-in device.
KEY FEATURES
• Free Quick Check
• Full Diagnostic hardware testing
• Shareable pass/fail device report
• Device Checks saved to your account
• View remaining Device Checks in your Profile
• Useful for buying, selling, repairing, or verifying a used iPhone
PRIVACY
Synapse runs hardware tests on your device. Your account is used to save purchased Device Checks and help you access them across signed-in devices.
Permissions may be requested for camera, microphone, location during GPS testing, motion sensors, Bluetooth, Face ID / Touch ID checks, and local network features when needed.
Apple, iPhone, Face ID, and Touch ID are trademarks of Apple Inc.
Synapse now supports more iPhones! We've lowered the minimum requirement to iOS 15, so devices from iPhone 6s and newer can now run the full diagnostic.
New in this update:
Added Compass and Barometer to the Full Diagnostic
New pre-run overview showing every test before you begin
Improved audio testing experience
The developer, Nexus Link LLC, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Not Collected
The developer does not collect any data from this app.
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- Nexus Link LLC
- Size
- 5.7 MB
- Category
- Utilities
- Compatibility
Requires iOS 15.0 or later.
- iPhone
Requires iOS 15.0 or later. - iPod touch
Requires iOS 15.0 or later. - Mac
Requires macOS 12.0 or later and a Mac with Apple M1 chip or later. - Apple Vision
Requires visionOS 1.0 or later.
- iPhone
- Languages
- English
- Age Rating
4+
- 4+
- In-App Purchases
Yes
- Full Diagnostic $2.99
- 10 Checks — Pro Pack $9.99
- 3 Checks — Best Value $4.99
- Copyright
- © 2026 Nexus Link LLC
