Source Defense alternatives for protecting the payment page (2026)
By Laís Peixoto
Growth Marketer, Proteside
Published
Source Defense alternatives fall into three families: script agents on the page (Feroot, c/side), external monitors that visit the site from outside (Reflectiz, SecurityMetrics) and modules of a CDN or WAF, the web application firewall of a delivery network (Cloudflare Client-Side Security, formerly Page Shield). Proteside takes a fourth approach: it verifies the payment shown against what the seller issued. The right pick depends on what your checkout accepts and on who acts when something changes.
Why teams evaluate other options
The checkout accepts more than cards
UPI, PromptPay, PayNow, Brazilian bank slips and crypto never pass through a form. The fraud swaps the beneficiary on screen, which calls for a check of what the shopper sees and copies.
Evidence for 11.6.1 in the same tool
Teams heading into a PCI DSS assessment look for script inventory and header monitoring in one report, without stitching sources together.
Store-by-store install, independent of the acquirer
Merchants who do not receive protection through their acquirer's SDK want one line of code their own team can place on the payment page.
The short list
| Option | How it works | Makes sense for | Comparison |
|---|---|---|---|
| Proteside | A script on the payment page checks every QR code, payment key, bank slip line, wallet address and card field against what your server issued, and blocks the swap before confirmation. | Merchants paid through instant rails such as UPI, PromptPay, PayNow or Pix, by card, by bank slip or in stablecoins, who need protection and PCI DSS evidence from a single install. | Source Defense vs Proteside |
| Feroot PaymentGuard e DXSecure | Inventories the scripts on payment pages, records justifications and integrity, and alerts on changes to content and headers; runtime policy enforcement is described as optional. | Card-centric operations that need script governance across websites and mobile apps, with a report for the assessor. | Feroot vs Proteside |
| c/side Script Security | A snippet on the page watches third-party scripts in real sessions, keeps a history of what each script loaded and blocks by combining CSP with its own rules, with no reverse proxy and no DNS change. | Teams that want detailed visibility into the behavior of every third-party script, with compliance dashboards and alerts in chat tools. | c/side vs Proteside |
| Reflectiz PCI Module | An automated browser visits payment pages from outside, on a schedule, with no code on the site; blocking, when triggered in the interface, injects a CSP policy that excludes a domain. | Teams that cannot or prefer not to place a script on the page and accept detection with human review. | Reflectiz vs Proteside |
| SecurityMetrics Shopping Cart Monitor | Scans the payment page from outside, at intervals, simulating the checkout, and alerts on new scripts and changes; the company itself describes the product as a detection tool and says it was not built to prevent. | Merchants already using the SecurityMetrics PCI portal (questionnaires, ASV scans) who want evidence for requirements 6.4.3 and 11.6.1 in the same place. | SecurityMetrics vs Proteside |
| Cloudflare Client-Side Security (antes Page Shield) | From the proxy, Cloudflare adds a report-only CSP header to a sample of pages and builds the inventory from browser reports; blocking happens through allow rules in the advanced tier. | Sites already behind Cloudflare that want script monitoring with nothing to install. | Cloudflare Page Shield vs Proteside |
Choose the category before the vendor
Pick the category before the vendor. Script agents such as Source Defense, Feroot and c/side control what runs on the page and meet requirement 6.4.3 with blocking in the shopper's browser. External monitors deliver the inventory with no code on the page, at the cost of watching simulated visits rather than real shoppers. CDN modules enforce policy at the edge, only for sites already on that network.
None of these three families, as far as public documentation describes, checks whether the QR, account identifier, bank-slip line or wallet address on screen is the one the seller issued. That check is Proteside's category, and it comes with script inventory and evidence for requirements 6.4.3 and 11.6.1 in the same install.
The options in detail
Proteside
Proteside records what is legitimate on each payment page (the details of each charge, the form fields, the authorized scripts) and continuously verifies, in the payer's browser, what is displayed, what is copied and where the data goes. When it detects a mismatch, it stops the action before the payment is confirmed and logs the attempt.
The script inventory and the change history form the evidence for PCI DSS requirements 6.4.3 and 11.6.1. Installation is one line of code on any e-commerce platform, or a single integration for platforms and payment providers, with a dashboard, API and alerts.
Proteside is the right choice when: Choose Proteside when your checkout is paid through instant rails, bank slips or stablecoins as well as cards, when you need the payee swap blocked in real sessions, or when you want protection and PCI DSS evidence without changing your CDN.
Feroot PaymentGuard e DXSecure
Feroot centers its offer on compliance: PaymentGuard covers requirements 6.4.3 and 11.6.1 with script inventory, justifications, integrity checks and an evidence report for the QSA. Public documentation cites integrations with alerting and operations tools, and coverage of iOS and Android apps alongside websites.
The point to watch for anyone paid outside cards is scope: the public material speaks of scripts and card data, with no mention of QR codes, payment keys, boleto (Brazilian bank slip) or crypto wallets. For those payment methods, a payee swap sits outside what the tool describes checking.
Feroot is the right choice when: your priority is script governance and PCI DSS evidence across websites and mobile apps, and your checkout is paid mostly by card.
c/side Script Security
c/side defines itself as a client-side security platform. Public material describes an inventory with the content history of each script, a vendor graph, alerts, dashboards for requirements 6.4.3 and 11.6.1 and an endpoint for receiving CSP reports.
Its public page on crypto cites the swap of a wallet address copied to the clipboard, which brings it close to the problem Proteside solves. Pix, boleto (Brazilian bank slip) and the QR codes of instant payment rails such as UPI or PromptPay do not appear in the public documentation we consulted.
c/side is the right choice when: you want the detail of each third-party script's behavior and a crypto address swap is already your main concern outside cards.
Reflectiz PCI Module
Reflectiz describes its own approach as agentless: a sandboxed browser simulates the user journey, inventories scripts (including inside iframes), monitors headers for requirement 11.6.1 and exports evidence for the QSA. The platform also covers privacy and offensive testing.
The vendor's own material explains blocking as a script that stays inactive on the page until triggered in the interface, when it starts excluding a domain through CSP. It is a design choice: detection first, human intervention second. Scams that appear only to one specific buyer are not observed by simulated visits.
Reflectiz is the right choice when: your internal policy forbids adding scripts to the payment page and your security team reviews alerts before acting.
SecurityMetrics Shopping Cart Monitor
SecurityMetrics is a PCI assessment company (QSA, ASV) and Shopping Cart Monitor fits into its portal: script inventory with justification, detection of content and header changes, alerts and an exportable log for the assessor, with nothing installed on the site.
The public material is candid about the limit: the tool was built to detect, the vendor says, and it works from snapshots taken at intervals. For teams that need the scam blocked while the customer is still on the page, the approach works as a complement to a real-session block.
SecurityMetrics is the right choice when: your PCI DSS assessment already goes through SecurityMetrics and you want payment page evidence integrated into the same portal.
Cloudflare Client-Side Security (antes Page Shield)
The feature, called Page Shield until March 2026 and now Client-Side Security, is available for domains proxied through Cloudflare. Documentation describes monitoring of scripts, connections and cookies, detection of malicious scripts and code changes, and content security rules that can block anything outside the allow list.
The documentation itself explains the mechanism: the report-only header goes out on a sample of responses, so a new script can take time to appear. Requirements 6.4.3 and 11.6.1 are covered in the advanced tier. Pix, boleto (Brazilian bank slip) and instant payment rails do not appear in the material.
Cloudflare Page Shield is the right choice when: your site is already behind Cloudflare, cards are the main payment method and sampled script monitoring satisfies your assessor.
How to evaluate an alternative
- 1Which payment methods does your page display? With UPI, PromptPay, PayNow, bank slips or a wallet address on screen, the tool has to verify that data, not only the scripts.
- 2Who acts when something changes? Automatic blocking in the shopper's session, or an alert for someone to review and adjust the policy?
- 3Who installs it? Your team on the payment page, the acquirer through its SDK, or the CDN at the edge? Each path decides who controls the protection.
- 4When is your next PCI DSS assessment? The report has to cite requirements 6.4.3 and 11.6.1, with inventory, authorizations and change history.
- 5How much time will operations have to maintain the policy? Script allowlists need review whenever the site changes; payment verification compares against what the server issued, with no list to keep.
Frequently asked questions
What is the best alternative to Source Defense?
It depends on what your checkout accepts. For cards with script blocking, Feroot and c/side sit in the same family; Reflectiz and SecurityMetrics suit teams that cannot place code on the page; Cloudflare suits sites already on its network. For UPI, PromptPay, PayNow, bank slips and crypto, payment verification appears in Proteside's public documentation.
What does a Source Defense alternative need to cover?
At minimum, inventory and authorization of third-party scripts, blocking in the shopper's browser and a report for the assessor. If your PCI DSS assessment asks for requirement 11.6.1, add header monitoring; if the checkout goes beyond cards, add beneficiary verification.
Who are Source Defense's competitors?
In the on-page agent family, Feroot, c/side, Jscrambler and HUMAN Security. Among external monitors, Reflectiz and SecurityMetrics. Among CDN or WAF modules, Cloudflare, Akamai, Imperva and F5. Proteside compares against all of them on these pages.
Does Proteside replace Source Defense?
It depends. On the web payment page, Proteside covers script inventory, the card form and requirements 6.4.3 and 11.6.1, and adds payment verification. When Source Defense arrives through the acquirer's SDK, the two can run side by side.
All guides
- Feroot alternatives
- c/side alternatives
- Jscrambler alternatives
- HUMAN Security alternatives
- Reflectiz alternatives
- SecurityMetrics alternatives
- Cloudflare Page Shield alternatives
- Akamai Client-Side Protection alternatives
- Imperva Client-Side Protection alternatives
- F5 Client-Side Defense alternatives
- All comparisons
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