Source Defense alternative: an honest comparison
Source Defense isolates third-party scripts in a sandbox and applies a permissions model to what each one may do. It is the most architecturally distinctive approach in this comparison, and it is a serious product.
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S
Source Defense
From $98/month
VS
Script Monitoring
From $99/month
TL;DR
Source Defense vs Script Monitoring
WHAT THEY DO WELL
The sandbox and permissions model is a genuinely different design: rather than watching what a script does, it constrains what a script can do. That is a strong idea and well executed.
WHERE TO CHECK CAREFULLY
A sandbox changes the execution environment of third-party scripts, so some vendor scripts need configuration work to behave correctly inside it. Budget integration time.
PRICING
Source Defense publishes pricing: Essentials is $98/month for 100,000 page views and one domain. Ours is published too: $99/month covers the same volume with unlimited domains, and there is a free plan under it.
Short on time? Scroll to which one to choose if you want the short answer.
Is Script Monitoring a good Source Defense alternative?
Yes, if your primary driver is PCI DSS 6.4.3 and 11.6.1 evidence and you want a free plan to evaluate on before committing. You want to constrain what third-party scripts are capable of rather than observe what they do, and you have the engineering time to tune a sandbox. It is a legitimately strong model. The rest of this page sets out where each product is genuinely stronger, with a capability table, so you can make the call on your own constraints rather than on ours.
Where Source Defense is strong
Taking this seriously, because a comparison where the other product has no advantages is not a comparison. These are real and they may well be decisive for you.
The sandbox and permissions model is a genuinely different design: rather than watching what a script does, it constrains what a script can do. That is a strong idea and well executed.
Mature product with a long history in the category and deep experience with enterprise deployments and QSA conversations.
Granular per-script permission policies, which map neatly onto the authorisation half of 6.4.3.
Like us, they have QSA-validated client-side controls, which is not true of every vendor in this list.
Where Source Defense has limits
Equally honestly, and stated as things to verify rather than as accusations.
A sandbox changes the execution environment of third-party scripts, so some vendor scripts need configuration work to behave correctly inside it. Budget integration time.
Detection is browser-based, so the same caveat applies as to any in-page agent.
Enterprise-oriented sales and deployment motion. There is no self-serve path to try it.
Published pricing, from $98/month, with 30-day retention on the entry tier.
Side by side
Capability comparison
Capability
Source Defense
Script Monitoring
Architectural approach
Sandbox and permissions on third-party scripts
Observe behaviour, hash the payload, block by rule
Payment-page script inventory for 6.4.3
Yes
Yes
Header change detection for 11.6.1
Yes
Yes
QSA-validated controls
Yes
Yes
Integration effort for vendor scripts
Higher, sandbox needs configuration
Lower, scripts run normally unless you block them
Free plan that does not expire
No
Yes, no credit card
Domains included
1 on Essentials
Unlimited on every plan
Payment pages included
2 on Essentials
Unlimited on every plan
Webhook alerts without an enterprise contract
No, Enterprise only
Yes, included in Pro
Full PCI dashboard on the entry plan
No, Basic until Professional
Yes, on the free plan
PCI and client-side security in one price
No, client-side is an add-on
Yes, one price covers both
Detection technique
Crawlers, plus a sandbox agent
In-page, plus server-side hashing
Session coverage
Not published
100% of sessions, no sampling
Server-side payload analysis
No, script contents not shown
Yes, every payload inspected
Human support on the entry plan
No, email from Professional
Yes, email on the free plan
Source Defense pricing, and ours
Source Defense publishes pricing. Essentials is $98/month for 100,000 page views, one domain and 30-day retention; Standard is $197/month for 250,000 views and three domains; Professional is $315/month for 500,000 views and ten domains; Enterprise is custom.
We publish ours: free for 1,000 page views a month, Pro from $99/month for 100,000 payment-page views, $499/month at 500,000 and $799/month at 1,000,000, overage at $0.0013 per page view, annual billing at 10 months instead of 12, and Enterprise on request.
Look at what their tiers count and ours do not: domains run one, three and ten across their plans and are unlimited on every plan of ours, so an estate of twenty checkout domains moves you up their pricing and changes nothing on our bill. Page views are the only unit we meter. The headline figures are close, so the differences worth weighing are retention, how many domains you run, and whether you can evaluate without talking to anyone.
S
Source Defense
From $98/month
Script Monitoring
Free
1,000 page views a month
Pro, 100,000 payment-page views
$99/month
500,000 page views
$499/month
1,000,000 page views
$799/month
Overage
$0.0013 per page view
Annual billing
10 months instead of 12
Enterprise
On request
Which one to choose
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Choose Source Defense if
You want to constrain what third-party scripts are capable of rather than observe what they do, and you have the engineering time to tune a sandbox. It is a legitimately strong model. Budget integration time, because some vendor scripts need configuration before they behave correctly inside the sandbox.
Choose Script Monitoring if
You want deployment measured in minutes rather than weeks, you would rather not change how vendor scripts execute, and you want to try it before talking to anyone. It is one tag from $99/month, with unlimited domains on every plan and full integrations on every paid plan.
Other comparisons
FAQ
Frequently asked questions
Yes, for teams whose primary driver is PCI DSS 6.4.3 and 11.6.1 evidence, who want published pricing, and who want to evaluate on a free plan rather than through a sales cycle. You want to constrain what third-party scripts are capable of rather than observe what they do, and you have the engineering time to tune a sandbox. It is a legitimately strong model.
Yes. Essentials is $98/month for 100,000 page views and one domain, Standard $197/month, Professional $315/month, Enterprise custom. Ours is published too: free for 1,000 page views a month, Pro from $99/month, overage at $0.0013 per page view. The headline figures are close, so compare retention and domain limits.
Yes, and for some combinations it is sensible. Running two client-side tools on the same payment page adds weight, so it is worth being deliberate about which one is the system of record for your PCI evidence and which is doing something else.
Yes, and it is worth asking every vendor in this category the same question. Our tag is integrity-checked on load: if what arrives in the browser is not the script we published, it does not run. A client-side monitor that an attacker can silently modify is worse than no monitor, because it keeps reporting all-clear while the page is compromised. Not every agent in this category does this, so put it to Source Defense as well.
Yes, this is the right thing to worry about, and the answer is that it should not. Installation is one first-party tag with no DNS or CDN change, and the tag is fail-open, so if our service is unavailable your page still renders. Most teams run monitor-only mode alongside their existing tool for a few weeks before switching the system of record.
Usually days rather than weeks. The tag goes in, you mark your payment pages with selector rules, and the inventory populates from live traffic immediately. The slower part is re-recording business justifications, and if you already wrote them for 6.4.3 they transfer directly.
Source Defense publishes its prices: Essentials is $98/month for 100,000 page views and one domain. Among tools that publish prices for PCI DSS 6.4.3 and 11.6.1: Script Monitoring is free for 1,000 payment-page views a month and $99/month (or $990 a year) for 100,000, with unlimited domains; cside is free for 2,000 payment-page views a month and $99/month for 100,000; DomDog is $999 a year for 100,000 page views on one domain and two payment pages; Report URI's PCI features start on its $164.99/month plan; and if your traffic is already on Cloudflare, Client-Side Security Advanced is $0.099 per 1,000 requests. Which is cheapest depends on your page views and how many domains you need.
Compare it against your own checkout.
Install the tag, mark your payment pages, and see what the inventory finds. Free forever on 1,000 page views a month, no credit card.
Free forever plan. No credit card.