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Wireless StreamingTLS 1.3 · mDNS Discovery

Local Wi-Fi & AirPlay Mirroring

Cable-free streaming over 5GHz Wi-Fi with mDNS discovery, SHA-256 certificate pinning, and native AirPlay.

5 min read•Last updated October 2026•Source docs
Supported Devices
iPhone / iPad (iOS 15+) & Android (8.0+)
Discovery Protocol
Bonjour / Avahi mDNS (_castsprint._tcp)
Encryption
Local TLS 1.2/1.3 + SHA-256 Pinning
Session Security
Connection-Scoped 6-Digit PIN
Recommended Band
5 GHz Wi-Fi 5 / 6 or Gigabit Ethernet Host
Target Latency
20 – 35 ms (iOS) / 45 – 65 ms (Android)

CastSprint provides encrypted, cable-free wireless mirroring across your local home or studio network. It completely eliminates third-party cloud relays, subscription servers, and account logins. Your video and audio remain 100% private on your local subnet.

100% Local LAN Security Model

Unlike commercial mirroring utilities that route unencrypted frames through external servers, CastSprint uses end-to-end local cryptographic pinning:

  • Ephemeral Local TLS: The desktop receiver generates a local self-signed X.509 certificate on launch.
  • SHA-256 Fingerprint Pinning: The client validates the server's certificate strictly against the pinned SHA-256 fingerprint broadcast over mDNS.
  • 6-Digit Random PIN: A connection-scoped PIN is generated for each session. Unauthorized devices on your Wi-Fi cannot connect or intercept your screen.
  • Zero WAN Exposure: No port forwarding or UPnP is required or recommended.

iOS Wi-Fi Streaming (CastSprint iOS App)

For the lowest wireless latency on iPhone and iPad (~20–35ms), use the dedicated CastSprint iOS companion app:

  1. Ensure both your iPhone and PC/Mac are on the same 5 GHz Wi-Fi network.
  2. Launch CastSprint Desktop. Note the 4-digit or 6-digit session PIN.
  3. Open CastSprint iOS on your phone.
  4. Select your desktop receiver from the discovered devices list.
  5. Tap Launch Broadcast Picker, select CastSprint, and tap Start Broadcast.
  6. Your screen streams via Apple ReplayKit / VideoToolbox H.264 into CastSprint Desktop.

System AirPlay Mode (Zero-App Wireless)

On macOS and Windows, CastSprint also provides zero-app wireless mirroring utilizing Apple's standard AirPlay 2 protocol:

  1. Ensure your iPhone and computer are on the same Wi-Fi network.
  2. In CastSprint Desktop, ensure the AirPlay receiver is set to Active.
  3. Swipe down to open iOS Control Center.
  4. Tap Screen Mirroring and tap CastSprint Desktop.
AirPlay vs Dedicated AppNative AirPlay is convenient for quick demos and presentations (latency ~80–150ms). For fast-paced competitive gaming (PUBG, COD Mobile, Genshin), use the CastSprint iOS app or wired USB for 20–35ms response time.

Android Wi-Fi & Discovery

CastSprint Android discovers local desktop receivers using multicast DNS (mDNS):

  1. In CastSprint Android, choose Secure Wi-Fi (LAN).
  2. Tap Configure / Discover PC to view nearby receivers.
  3. Select your PC, enter the 6-digit session PIN displayed on your monitor, and tap Save.
  4. Tap Start Mirroring and allow the system capture prompt.

Esports Network Optimization

For flawless 60 FPS wireless mirroring without stutter:

  • Use 5 GHz or Wi-Fi 6 (802.11ax): 2.4 GHz channels suffer heavy interference from Bluetooth, microwaves, and neighboring routers.
  • Gigabit Ethernet Host: Connect your gaming desktop PC to your router via Ethernet cable. Having only the mobile device on Wi-Fi halves wireless congestion.
  • Avoid Guest Wi-Fi: Guest networks enforce "AP Client Isolation", which blocks devices from communicating with each other.

Firewall Configuration

If CastSprint Desktop does not appear in discovered lists, allow TCP port 27183 in Windows Defender Firewall:

PowerShell (Administrator)
New-NetFirewallRule -DisplayName 'CastSprint Receiver' -Direction Inbound -LocalPort 27183 -Protocol TCP -Action Allow -Profile Private