Zero-instrumentation monitoring
See everything your
servers are doing.
aacyn monitors your apps and infrastructure — request rates, errors, response times — without touching your code.
It runs on your hardware, so your data stays yours.
Free and open source. Forever.
What is aacyn?
A monitoring tool that watches your servers from the operating system level — no SDKs to install, no code changes, no cloud account required.
Monitor
See every request, error, and slow response across your services. aacyn uses a Linux technology called eBPF to observe traffic at the kernel level — no agents or SDK installs needed.
Self-hosted
Runs on your hardware — a mini PC, a server rack, or a Docker container. Your telemetry data never leaves your network. No cloud vendor lock-in.
Free and open source
No per-host fees. No per-GB surcharges. No surprise invoices. Apache 2.0 licensed — use it, modify it, ship it. All features included, no tiers.
See inside your Docker stack in 30 seconds
Add one service to your docker-compose. The dashboard lights up automatically — every connection between your containers appears without touching a single line of application code.
services:
# ... your existing services ...
aacyn:
image: ghcr.io/aacyn/sidecar:latest
privileged: true
pid: host
ports:
- "3001:3001" # Dashboard
Real dashboard output — nginx → node → postgres topology discovered automatically via eBPF.
Ingest millions of events per second
Most monitoring tools parse JSON on every incoming request, which limits throughput. aacyn also accepts a compact binary format that skips parsing entirely — the bytes from your HTTP request go straight into storage.
The result: over 5 million events per second on a single box. That's 16× faster than JSON-only ingestion.
Query 5 million events in under a millisecond
aacyn stores data in a format optimized for analytics — instead of reading entire rows, it reads only the columns you need. Combined with modern CPU acceleration, this makes searching, filtering, and aggregating nearly instant.
Your data never leaves your network.
aacyn runs on your hardware and stores everything locally. There is no cloud backend. The only outbound request is a daily license check — a 200-byte ping that contains no telemetry data.
See it in action
Deploy aacyn on your cluster and see every TCP connection — between your services, your databases, and external APIs — captured at the kernel level with zero code changes.
Deploy aacyn and set NEXT_PUBLIC_AACYN_API_URL to see live cluster topology here.
aacyn is free and open source.
Apache 2.0. No tiers, no limits, no phone calls from sales.
- All features unlocked — Golden Signals, binary ingestion, Grafana plugin, cold storage
- Self-hosted, your data never leaves your network
- Community-supported via GitHub Discussions and Discord