“CTFd is free.” — Everyone who hasn’t tried to actually run a CTF on it.

If you’re planning a Capture The Flag competition and you’ve been told CTFd is the free option, you’ve been told half the story. The software itself? Yes, open source. No license fee. But running a CTF that doesn’t crash under load, that your participants can actually reach, and that someone is awake to fix at 2 am when something breaks? That’s a different conversation.

Let’s break it down honestly.

The “Free” Route: Self-Hosting CTFd

CTFd’s open-source code is genuinely free to download and run. If you’re a developer who’s comfortable with Docker, Linux servers, Nginx, MariaDB, and Redis — great. You can spin it up yourself.

But here’s what “free” actually involves:

• Cloud server costs. You need a VM somewhere. AWS, Azure, GCP, DigitalOcean — take your pick. A decent server that won’t fall over when 100 people hit it simultaneously will run you somewhere between $40–$150/month. For events with traffic spikes (which CTFs famously have), you either overprovision and overpay, or you hope for the best.

• A domain name. Not expensive, but not free either. ~$10–15/year.

• SSL certificate setup. Free with Let’s Encrypt, but you still need to configure it.

• Your time. This is the one people forget. Setting up CTFd properly — configuring Nginx rate limiting, securing the database, setting up email, testing load, handling DDoS protection — takes hours. Then there’s event day, where you need someone monitoring the server and ready to respond when things break.

One community CTF organizer described it well: after setting up the platform, they still had two server outages during the event. For a competitive CTF, “didn’t last long” can ruin someone’s run.

The Hosted CTFd Route: Not Exactly Free Either

CTFd does offer managed hosting, so you don’t have to deal with servers yourself. Here’s what that looks like after their updated 2025 pricing (effective March 15, 2025):

And there’s a new email overage charge: if you exceed your plan’s monthly email limit, additional emails cost $1.80 per 1,000. The Basic plan gives you 2,000 emails — which goes fast when you’re sending registration confirmations, password resets, and competition updates.

Important: these are monthly charges billed for a minimum of one month, even if your CTF only runs for a weekend.

So the “free” platform ends up costing you at minimum $50–60 for a single event hosted. And if you want programming challenges, Slack/Discord integrations, or webhooks — that’s the $100–$120/month Plus tier.

The Hidden Cost Nobody Talks About: Your Team’s Time

The real cost of CTFd — self-hosted especially — is the engineering time you pour into it before and during your event:

• Setup and configuration: 4–8 hours for someone who’s done it before, more for first-timers

• Challenge deployment infrastructure: CTFd handles the scoreboard, but running actual challenge containers (web exploits, pwn challenges, etc.) requires separate infrastructure you manage yourself

• Event day monitoring: someone needs to be on-call — a real person, not doing other things

• Post-event cleanup: shutting down servers, exporting data, and paying the month’s cloud bill

If your team values their time at even a modest hourly rate, those hours add up fast — and they don’t show up anywhere on CTFd’s pricing page.

What Simulations Labs Costs — and What You Actually Get

We built Simulations Labs because we kept running into these exact problems when trying to run CTFs for organizations. Our pricing works differently: instead of charging by the month regardless of your event schedule, we price by participants — so you’re paying for the actual scale of your event, not for infrastructure you rent and then tear down.

What’s included across all plans: unlimited competitions, unlimited challenges, analytics dashboards, and no engineering setup, no server management, no “who’s on-call tonight” conversation.

The free tier is genuinely usable for small internal workshops or team tryouts with up to 10 participants — not a demo that expires in 14 days.

The Real Comparison

So, Is CTFd Really Free?

The software is free. Running a CTF is not.

If you have a developer on your team who enjoys infrastructure work, loves Docker, and doesn’t mind being on standby during your event — CTFd self-hosted is a legitimate option. Lots of community CTFs run on it, and many of them do it well.

But if you’re running a CTF for business purposes — talent assessment, employer branding, a training program, a client-facing event — the question isn’t just “what does the software cost?” It’s “what does this event cost us end-to-end, and what happens if something goes wrong?”

That’s where the math shifts.

Start free on Simulations Labs — no credit card required.

Have you run a CTF on CTFd before? We’d love to hear how it went — the good parts and the painful parts.