Know where the network is broken, and whose fault it is.
Synth Monitor tests your applications and the paths to them from agents everywhere. When something degrades, it names the network at fault, with the evidence to send that provider.
| Agent | Problem | Where |
|---|---|---|
| Frankfurt-1 | 14% loss | hop 4 · AS64500 |
| London-2 | 13% loss | hop 5 · AS64500 |
| Paris-Office | 12% loss | hop 6 · AS64500 |
| Singapore-1 | Healthy | via AS64511 |
Most monitoring tells you something is slow. Then the real work starts.
Synth Monitor answers the questions your team spends the first hour of an incident on.
Is it us?
Tests from your own sites, laptops and the cloud separate a local problem from one on the internet. The diagnosis says plainly what is fine: “your network and the destination are fine.”
Where exactly?
Multi-flow traces show the hop where real loss starts, the latency jump against the last healthy path, and route changes and BGP activity lined up on one timeline.
Whose network?
Every hop is mapped to its network: your site, your access ISP, a transit provider or the destination. Across agents, the culprit is the network they have in common.
Loss you can trust, on the hop where it starts.
Routers that rate-limit traceroute replies make most path tools cry wolf. Synth Monitor counts loss only when it continues downstream, traces several flows to reveal load-balanced branches, and remembers every path so you can slide back to the moment things changed.
- Real vs. rate-limited loss, per hop
- Each hop's network, role and location
- Path time travel with a BGP activity overlay
| Hop | Router | Network | Avg | Loss |
|---|---|---|---|---|
| 1 | 192.168.1.1 | private | 1.2 ms | 0% |
| 2 | 100.64.12.1 | AS64496 Access-ISP | 6.8 ms | 0% |
| 3 | 198.51.100.9 | AS64496 Access-ISP | 8.1 ms | 0% |
| 4 | 203.0.113.14 | AS64500 Transit-Example | 19.6 ms | 14% real |
| 5 | 203.0.113.77 | AS64500 Transit-Example | 24.3 ms | 13% real |
| 6 | 192.0.2.10 | AS64510 Example-Cloud | 25.1 ms | 13% real |
Every layer between your users and your service.
Hop-by-hop paths
Paris traceroute over several flows, so load-balanced branches show up. Loss is judged real only when it continues to the target.
- ECMP branches
- MPLS labels and hidden tunnels
- DSCP re-marking
- Path MTU and black holes
BGP routing
Your prefixes watched from public route collectors and your own routers (BMP).
- Origin and sub-prefix hijacks
- Route leaks (valley-free)
- RPKI-invalid announcements
- Route changes on your paths
DNS from the root down
Each agent resolves from the root servers itself and reports every referral, so you see which server is slow or broken.
- Root, TLD and authoritative timing
- Full DNSSEC chain validation
- Lame and glueless servers
Web, API and browser
From a single HTTP check to multi-step API flows and real-browser journeys with screenshots.
- Multi-step API with variables
- Page load: FCP, LCP, waterfall
- Scripted browser transactions
- FTP, FTPS, SFTP
Voice and SIP
RTP-sized traffic between agents with the ITU E-model, plus SIP OPTIONS and REGISTER checks.
- MOS and R-factor per direction
- Jitter buffer discards
- Burst loss
- SIP over UDP, TCP, TLS
Agents everywhere
One command on Linux, Docker, macOS or Windows, launched in your AWS account, or our shared agents.
- Laptop agents: Wi-Fi, gateway, VPN
- Agent-to-agent tests
- Auto-update
- Outbound HTTPS only
Send the provider a report they can't argue with.
One click turns a diagnosis into a provider-ready report: verdict, UTC timeline, source networks and the hop-by-hop paths. Print it, or share a public link with the provider.
Target: api.example.com (192.0.2.10) tcp/443
Problem since: 2026-10-21 14:05 UTC (ongoing)
VERDICT: packet loss begins in AS64500 Transit-Example
first lossy hop: 203.0.113.14 (hop 4), 14% loss
loss persists to the destination: real, not ICMP rate-limiting
3 of 4 source networks affected; AS64511 path healthy
TIMELINE (UTC)
13:59 route change: AS64496 → AS64500 → AS64510
14:05 loss starts (Frankfurt-1, London-2, Paris-Office)
See whose network it is, on your own traffic
Free during the beta. Install an agent in one command and your first test is live in minutes.