42 tools 100% client-side Open source
Free DevOps tools and hands-on training, right in your browser.
OpsCanopy is where engineers check configs, queries and network math — and where developers learn to become DevOps engineers. Nothing you paste leaves your device, and there is no account. Ever.
- Network
- 10.20.0.0
- Broadcast
- 10.20.3.255
- Netmask
- 255.255.252.0
- Wildcard
- 0.0.3.255
- Usable range
- 10.20.0.1 – 10.20.3.254
- Usable hosts
- 1,022
- Class
- Private (RFC 1918)
/22 → 1,022 usable hosts
Exact answers, not approximations.
- GitHub Actions 82 conformance cases Every operator, coercion and glob is pinned to a versioned corpus (gha-2026.10) that the test suite runs on each build.
- jq Real jq 1.8.2 Not a re-implementation: the actual jq binary compiled to WebAssembly, running in your tab.
- Alertmanager Routes like the router Nested routes, continue, matchers and grouping are modelled the way Alertmanager itself resolves them.
- IP & hashing RFC and NIST vectors Exact BigInt arithmetic for IPv4 and IPv6, checked against published test vectors rather than eyeballed.
Jump back in
The tool index.
Focused, single-purpose utilities for platform and DevOps engineers — every one live, exact and a single bookmark away.
GitHub Actions Expression Tester
CI/CD
Evaluate ${{ }} expressions and simulate workflow triggers.
Open tool- Alertmanager Route Tester Walk your Alertmanager route tree against alert labels to find the matching receiver(s) - in your browser.
- Prometheus Relabel Tester Test Prometheus relabel_configs against sample labels and see exactly what survives.
- AlertLint Unit testing for Grafana Loki alert rules.
- jq Playground Test jq expressions against your JSON — real jq 1.8.2 running in your browser.
- Certificate Decoder & Chain Checker Decode PEM certificates, check chain order, and verify signatures — in your browser.
- Subnet Calculator Network, broadcast, mask and host range from any IPv4/IPv6 CIDR.
- JWT Decoder & Encoder Decode, verify, and sign JWTs — HS/RS/PS/ES/EdDSA — with a built-in key generator.
- Cron Expression Tester Explain any cron expression in plain English — and see the next runs.
From developer to DevOps engineer in 90 days.
A guided path — one focused lesson a day, and a story-driven mission you play in an in-page terminal to fix a broken system at the end of every week. All 90 days and 10 missions are live now — open from day one.
- 90
- days
- 5
- phases
- 10
- browser missions
- ~80
- hours core
Three of the ten missions
- Week 1 Server Down! The web server died at 2 a.m. and you're the only one awake — find it, fix it, bring it back. Play
- Week 4 Docker Rescue A containerized app is crash-looping on a fresh host — get the stack up without touching the source code. Play
- Week 11 Kubernetes Chaos One pod is stuck starting, the rest are CrashLoopBackOff — read the events and restore order. Play
student@prod-web-01:~$ ps aux --sort=-%cpu | head -3USER PID %CPU COMMANDroot 4521 94.0 /opt/scripts/nightly-backup.shstudent@prod-web-01:~$ kill 4521student@prod-web-01:~$ systemctl restart nginxstudent@prod-web-01:~$ curl -sI localhost | head -1HTTP/1.1 200 OK# 02:07 — the site is back. You did that.Staged roadmaps & hands-on guides.
Go from the fundamentals to job-ready with staged career roadmaps and deep, practical guides — Linux, Docker, Kubernetes, AWS and networking. Self-paced, and you can practise with the tools as you go.
Why OpsCanopy
One set of guarantees, not twenty tabs.
Every OpsCanopy tool runs as static JavaScript in your browser. There is no backend to receive your rules, configs or logs — no uploads, no telemetry on your inputs, no account to create. Close the tab and it’s gone.
- ONE PLACE Everything in one tab. Bookmark one site instead of a dozen. When you need a converter, validator, or calculator, it's already here — same look, same shortcuts, no re-learning.
- ALWAYS FAST Instant, every time. Every tool is static and client-side, so there are no server queues or cold starts to wait on — pages load instantly, whether you or ten thousand people hit them at once.
- NO GATE Nothing to unlock. Every tool, guide and practice exam is open to anyone — no paywall, no trial, no form. Open the page and start working.
- requests (this page)
- —
- your input
- 0 bytes sent
- uploads
- 0
- cookies (this origin)
- —
- accounts
- 0
Notes from the incidents.
Short, practical write-ups on the problems these tools exist to solve — why a pipeline went red, where an alert vanished, what a query actually means.
- chown command in Linux: change file owner and group The chown command in Linux explained: user:group syntax, chown -R and symlinks, --reference, chgrp, chmod vs chown, and fixing Docker volume permission errors with numeric IDs.
- chmod command in Linux: syntax, examples and common mistakes The chmod command in Linux explained: octal and symbolic modes, chmod +x, chmod -R and its traps, setuid, setgid and sticky bits, umask, and how to fix Permission denied.
- Kubernetes Service has no endpoints: find the selector bug A Kubernetes Service has no endpoints, or a Deployment says selector does not match template labels? One bug, two symptoms, and how to trace both to a fix.
Verify the AI
Check an AI’s answer against the real computation.
Paste the numbers an assistant gave you next to the input it was given. The tool recomputes them exactly, on this page, and marks each claim — the same check the subnet, cron, timestamp and Base64 tools carry under their result panel.
| field | claimed | computed | verdict |
|---|---|---|---|
| Broadcast address | 192.168.1.255 | 192.168.1.255 | match |
| Usable hosts | 256 | 254 | mismatch |
FAQ
Questions, answered.
Tap a question to expand the answer.
Are OpsCanopy tools really free?
Yes. Every tool is completely free with no paywalls, usage limits, or premium tiers. There is no account requirement of any kind — open a tool in your browser and start using it immediately.
Do I need to sign up to use these online DevOps tools?
No. There is no signup, login, or email capture. Open any tool in your browser tab and use it immediately — no account, no cookie banner, no friction. Analytics is cookieless by default in the EU, the UK and Switzerland, and uses a single first-party cookie elsewhere; either way you can change it on the privacy page.
Is my data uploaded to a server when I use the tools?
No. Every tool runs 100% client-side in your browser tab; nothing you paste is logged, stored, or uploaded. Your data never leaves the browser.
Is it safe to paste a JWT or config into a browser-based tool?
On OpsCanopy, yes. Decoding and parsing happen entirely in local JavaScript — nothing you paste is ever transmitted, which you can verify in the browser network tab (the only outbound traffic is aggregate page analytics, disclosed in our privacy policy). As general hygiene, never share signing secrets with any third party, but OpsCanopy uploads none of your input.
More questions (5)
Do the tools work offline?
Once a tool page has loaded, it keeps working even if you disconnect from the internet, because all processing is local and there is no backend to call. Going offline is also an easy way to verify the client-side privacy claim yourself.
Who are these browser-based DevOps tools for?
DevOps engineers, SREs, sysadmins, platform and backend engineers — anyone who needs quick subnet and CIDR math, cron schedules, PromQL or LogQL queries, JWT, Base64 and hash utilities, timestamp conversion, GitHub Actions validation, or Kubernetes resource sizing without installing anything.
Why use these instead of asking ChatGPT or Claude?
Use both — for different jobs. An AI assistant is excellent at explaining concepts and drafting configs, but it generates plausible text rather than computing answers, and exact arithmetic is a documented weak spot: subnet boundaries, cron schedules, epoch conversions and regex behaviour routinely come back looking right and being wrong. OpsCanopy tools compute answers deterministically — real parsers, exact math — and recompute instantly as you tweak the input, with no re-prompting, no token cost and no rate limits; once a tool page has loaded, it keeps working offline. Nothing you paste is ever transmitted, so logs, tokens and configs stay on your machine. Several tools even make handy AI checkers: run the same subnet, cron expression or timestamp through them and you get the ground truth to compare against.
How is OpsCanopy different from other online developer tool collections?
Most tool collections focus on generic formatters. OpsCanopy specialises in DevOps and SRE workflows — CIDR planning, cron, PromQL and LogQL, Kubernetes capacity, CI validators — with the same guarantees throughout: free, no signup, 100% client-side, nothing uploaded or logged.
I want to become a DevOps engineer — where do I start?
Start with OpsCanopy Learn at /learn. It pairs a staged DevOps career roadmap (/learn/roadmaps/devops) with free, hands-on guides covering Linux, Docker, Kubernetes, AWS and networking — going from the fundamentals to job-ready. As you read, you can practise immediately with the matching tools in the catalog, no signup required.
Find your tool. Skip the install.
Exact, private and instant. Open the catalog and put the right utility to work in your next deploy.