Best alternative to Intruder, meet Defenso.
Intruder runs continuous vulnerability scanning with a clean UI, aimed at security-conscious companies. Defenso gives you the same active probing plus a managed firewall, uptime and a mobile alarm, priced for developers instead of security departments.
Why teams pick Defenso over Intruder.
Intruder is a polished vulnerability scanner. It runs authenticated and unauthenticated scans against your infrastructure and apps, probes for real weaknesses rather than only fingerprinting versions, and re-scans when new threats emerge. For a company that needs a clean, continuous scanning service and a report to show auditors, it is a genuinely good tool.
Developers look for an Intruder alternative when they realise a scanner is only half the job. It finds the problem, but it does not stop the attack, watch whether the site is even up, or catch the API key you just pushed to GitHub. And its pricing is built for security teams, not for a solo founder shipping fast. Defenso keeps the important part, actively probing your app rather than just watching for known patterns, and adds a firewall, monitoring and repo scanning at a price that makes sense for indie developers and small teams.
Switching from Intruder to Defenso.
Defenso is built on the same principle that makes Intruder useful: probe the app, do not just watch it. The scheduled pentest actively tests your live site, grades it A to F and attaches a fix to every finding, and the deep pass on the Max plan reaches ports, admin panels and misconfigurations a surface scan misses. This is the active, attacker-style testing that usually carries a security-team price tag elsewhere.
The difference is everything wrapped around the scan. A one-line SDK enables a managed WAF with 50k+ rules and automatic API rate limiting, so the vulnerabilities Intruder-style scanning would only report are actively blocked. The same account monitors uptime, SSL and domain expiry, scans your repo for leaked secrets, and fires a call-style alarm to your phone when it matters, all failing open with about 4ms added.
You can run Defenso next to Intruder with no migration: nothing to uninstall, nothing to move. Compare the findings and the price, and keep what gives your team more. The free tier needs no card and includes a monthly pentest, and annual billing runs about 25% below monthly.
Compare Defenso with the rest.
How to switch from Intruder without a monitoring gap.
Migrating off Intruder is a five-minute job, not a project. You keep Intruder live while you set Defenso up, move your sites and alerts across, switch on the WAF and pentest Intruder never offered, and only then cancel. Here is the exact order.
-
01
Keep Intruder running while you set up
No rip-and-replace. Create a free Defenso account and add your sites there first, and Intruder stays live the whole time, so there is never a monitoring gap during the move.
-
02
Add your sites and endpoints
Point Defenso at the same URLs, domains and API endpoints you watch in Intruder. Uptime checks, SSL and domain-expiry monitoring and a public status page turn on the moment a site is added: no agent to install, no DNS change.
-
03
Wire up the alerts you already use
Connect email, Slack, Discord, Telegram or a signed webhook, and install the Defenso Alerts phone app. The call-style Alarm level rings through silent mode and Do Not Disturb for the 3am outage you cannot sleep through, something Intruder cannot do.
-
04
Turn on the security Intruder does not have
This is the real upgrade: a managed WAF in one SDK line, a scheduled pentest that grades your site A–F, repo and secret scanning, and active deception, all in the same account, at no extra vendor. Monitoring and security stop being two bills.
-
05
Run both for a cycle, then cancel Intruder
Watch the two side by side for a billing cycle. Once you trust the Defenso alerts and grades, cancel Intruder and consolidate. Most teams find they were paying for uptime and still had no security layer at all.
Frequently asked questions.
Everything people ask before they switch from Intruder. Still unsure? We are one message away.
For developers and small teams, yes. Defenso actively probes your app with a graded pentest and scheduled rescans the way Intruder does, then adds a managed WAF, uptime monitoring, repo secret scanning and a phone alarm in one account at developer-friendly pricing.
It probes. The pentest tests your live site like an attacker, and the deep pass on the Max plan checks ports, admin endpoints and server misconfigurations. Findings are graded with fixes, not just flagged.
It blocks, not just reports. The managed WAF with 50k+ rules and automatic API rate limiting stops the vulnerabilities while you fix them, and you also get uptime monitoring, repo scanning and a call-style alarm that a scanner alone does not include.
Yes, and it needs no card. Free covers a monthly surface pentest, basic managed WAF, uptime and a status page. Paid plans add deep pentests, repo scanning and unlimited scans, with yearly billing about 25% cheaper.
Get more than monitoring, for free.
No card, no install. Add a site and get uptime, a managed firewall, a pentest and a phone alarm in one account.