Your video call froze. Your game just spiked to 300 ms. Your Wi-Fi says "Excellent" and the speed test looks fine. NetDiag+ tells you what's actually wrong — and where, in the chain from your phone to the server, the problem lives.

31 network tools on stock Android. No root, no account.

FIND THE WEAK LINK
• Health Score: one run of about 40 seconds gives a 0–100 score and a verdict for your Wi-Fi, router and ISP
• Bufferbloat: lag under download and upload load, graded A+ to F, with download and upload speed
• Latency Dashboard: latency, jitter and loss to the services people in your market use, worst first. Curated for Saudi Arabia and the Gulf, Turkey, Russia and Egypt; a global set elsewhere

MEASURE
• Ping (real ICMP, no fake TCP fallback)
• Path MTU (DF-bit binary search — find fragmentation)
• Traceroute + MTR (per-hop loss and latency)
• Speed Test (Cloudflare, with jitter — not just Mbps)
• STUN / NAT type (spot symmetric NAT that breaks P2P)
• Wi-Fi info (signal, channel, 2.4 GHz overlap warning)

INSPECT
• DNS lookup + Encrypted DNS (DoH; compares 3 resolvers)
• Reverse DNS, WHOIS (with IANA referral)
• TLS Inspector (full cert chain, expiry)
• SSL Checker (probes TLS 1.0-1.3 separately)
• HTTP/3 + QUIC reachability
• HTTP headers + redirect chain

SCAN
• LAN Scanner (concurrent /24 sweep)
• Port Scanner (19 common ports)
• TCP Ping (when ICMP is filtered)
• mDNS / Bonjour browse

DIAGNOSE
• Network Passport (one-tap composite report — shareable)
• Site Reach (DNS → TCP → TLS → HTTP; names the failing layer)
• VPN Check (should you use a VPN on this network? IP + NAT + DNS leak + geo — 4 probes, one answer)
• Host Monitor (watch a service for outages)
• Subnet Calculator (offline)
• IP Info (geolocation, ISP, AS; flags mobile/proxy/hosting)
• Network Info (transport, DNS, MTU)

BUILT TO BE TRUSTED
• No account, no sign-up
• Tests run on your device, not on our servers
• Usage statistics via Firebase Analytics, linked to a device ID, not to your name or email
• Test history stays local
• Open protocols only (ICMP, TCP, UDP, HTTPS, DoH)

WHO IT'S FOR
• Gamers chasing the lag spike that ruins ranked matches
• Remote workers whose Zoom freezes while the speed test says fine
• Anyone who wants to check that their ISP delivers what they pay for
• Network engineers, SREs, home-lab tinkerers who want real numbers

FREE AND PREMIUM
• Every tool is free. An optional one-time Premium, not a subscription, adds 30- and 90-day Bufferbloat trends and every market in the Latency Dashboard.
• Some results, mostly ones that find a problem, show an offer for a VPN service. That offer is the only advertising in the app.

Support: netdiag.online/support/
Privacy: netdiag.online/privacy/