cside Reviews & Product Details

What is cside? cside is a browser-layer security platform that gives organisations complete visibility and control over the third-party JavaScript running on their websites. It intercepts every script before it reaches the user, captures the full payload, and analyses runtime behaviour in real time. Third-party scripts power modern websites. Analytics, chat, payments, advertising, and session replay tools all inject JavaScript that runs directly in your visitors' browsers. You didn't write that code. You don't control when it changes. And you have no idea what it does at runtime. That is the client-side blind spot. The three problems cside solves 1) Every third-party script is a blind spot. Analytics, chat, payments, ads: you didn't write it, you don't control it, and you have no idea what it does at runtime inside a real browser. 2) PCI DSS 4.0.1 requirements 6.4.3 and 11.6.1 are now enforced. Most companies have no idea how to meet them, and their existing vendors don't cover it. WAFs, CDNs, and tag managers were never built for this problem. 3) AI agents and bots are now targeting high-value web workflows including checkout, login, and form submission in ways that WAFs and CDN-layer tools were never designed to catch. The attack surface has moved into the browser. The tools haven't. What you get with cside 1) Visibility you have never had. Every script on every page, classified, behavioural-profiled, and monitored continuously. Not what a scanner saw on its last crawl. What actually ran in a real user's browser, in real time. 2) Compliance, done. 6.4.3 and 11.6.1 documentation generated automatically. Auditor-ready output without manual effort. QSA-validated. No CSV exports to fill in by hand. 3) Real-time blocking. Malicious or anomalous script behaviour stopped at the browser layer before data leaves the page. Not flagged for review after the fact. Stopped before exfiltration occurs. Why CSPs and crawlers cannot solve this A Content Security Policy tells the browser which domains are allowed to load scripts. It has no visibility into what those scripts execute. A script served from a trusted domain, after being compromised through a supply chain attack, passes every CSP check and still skims card data from your checkout page. Crawlers and scanners have a different problem. Bad actors detect them and serve clean content to the scanner, then flip to malicious for real users. What the scanner saw and what your customers experienced are two different things. WAFs and CDNs operate at the network layer. They cannot see inside the browser. They check what loads, not what executes. cside sits in the delivery path of every script. It captures what scripts actually do in real user sessions. Deployment: One script tag. Under ten minutes. No managed crawl setup, no session tokens, no captcha bypasses required. Pricing: Free tier available to see your script exposure before buying. Business and Enterprise tiers for teams managing compliance, multi-domain environments, and advanced governance. Transparent pricing. No contract required to prove compliance to your QSA before you commit. Frequently asked questions 1) What makes cside different from a Content Security Policy?: A CSP controls which domains scripts can load from. It cannot analyse what those scripts execute at runtime. cside captures the full payload of every script and analyses its behaviour inside real user browsers, giving you the runtime visibility that CSP was never designed to provide. 2) What PCI DSS requirements does cside address?: cside is built specifically around requirements 6.4.3 and 11.6.1 of PCI DSS 4.0.1. It generates the authorised script inventory required by 6.4.3 and provides the ongoing change detection and monitoring required by 11.6.1, with QSA-validated audit-ready output. 3) How is cside different from a WAF or CDN security feature?: WAFs and CDNs operate at the network or server layer and have no visibility into what JavaScript executes inside a user's browser. cside operates at the browser layer. It is a dedicated product for client-side security, not a feature bolted onto an existing network tool. 4) Does cside detect AI agents and bots?: Yes. cside detects AI agents and bots targeting high-value web workflows including checkout, login, and form submission, covering a threat class that network-layer tools were not designed to address.

Seller

cside

Discussions

cside Community

Languages Supported

English, French, Japanese, Dutch, Portuguese, Spanish

Overview by

Mike Kutlu

Pricing

Pricing provided by cside.

Free Plan

Free

Business Plan

Starting at $99.00

Per Month

View More Pricing Information

Top-Rated Alternatives

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User Insights

Average based on 12 real user reviews.

Typical contract price

$0k - $0k

Per Month

cside Integrations

(1)

Integration information sourced from real user reviews.

Verified User in Marketing and Advertising

Small-Business (50 or fewer emp.)

5/28/2026

"Great price to protect and secure marketing data"

5/5

What do you like best about cside?

In terms of bang for your buck, Cside came out on top compared to other tools we looked at. They have really strong data collection for fingerprinting and AI agent detection with flexibility on how we can use the data. Review collected by and hosted on G2.com.

What do you dislike about cside?

There were some specific features missing that other platforms had, but the huge step up in price just didn't make the other platforms worth it. That being said, the Cside team are very proactive and has committed to building new features for us when we ask for them. Review collected by and hosted on G2.com.

What problems is cside solving and how is that benefiting you?

As a privacy-first analytics agency, we try to provide a more holistic service by using Cside to report on fraudulent web traffic, bot traffic and to protect against script injections targeting outdated marketing tags. Cside s also great for auditing website scripts to protect against PII leaks and thus privacy fines.

Clients are really happy with this approach as they are often looking at an all-in-one solution. Using Cside has been a great differentiator for us because it's not just making marketing that we offer now, it's marketing security too, which is a great USP. Review collected by and hosted on G2.com.

Response from Simon Wijckmans of cside

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Thank you very much for your feedback. We do everything we can to provide a good service at a fair cost. Thanks for being one of our early customers of our AI agent detection product.

Excited to continue working with you.

Frédéric B.

Director of Engineering

Mid-Market (51-1000 emp.)

1/8/2026

"A simple PCI DSS solution backed by outstanding support"

4.5/5

What do you like best about cside?

cside was straightforward to implement on our payment pages and cleanly covers PCI DSS requirements 6.4.3 and 11.6.1. The application itself is extremely intuitive, and it’s easy to understand where to go and what to do without needing to read through documentation.

Integration was simple and non-invasive. The implementation required little to no development effort and was ready to be rolled out within a few days. cside proxies our JavaScript by injecting its script first on the page, which allows it to monitor third-party scripts as well as HTTP header changes without adding unnecessary complexity.

Once in place, day-to-day usage is minimal. We receive weekly email reports that surface any relevant changes, and we only need to step in when action is actually required.

Support has been outstanding. We have direct access to the team through a dedicated Slack channel, and response times when issues arise are consistently impressive. Review collected by and hosted on G2.com.

What do you dislike about cside?

The product is still relatively new, and there are some rough edges and occasional issues. That said, the team’s fast turnaround when problems arise significantly reduces the impact of these friction points. Review collected by and hosted on G2.com.

What problems is cside solving and how is that benefiting you?

cside helps protect our payment pages against client-side attacks by monitoring both third-party JavaScript and HTTP header changes in real time. This directly addresses PCI DSS requirements around script integrity and unauthorized modifications without requiring us to build or maintain a custom solution.

For us, the benefit is reduced risk and lower operational overhead. We gain clear visibility into what is running in the browser and how headers evolve, faster detection of unexpected changes, and confidence that our payment flows remain compliant without slowing down delivery. Review collected by and hosted on G2.com.

Response from Simon Wijckmans of cside

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Thanks for sharing your experience Frédéric. We're always excited for opportunities to make our product better and are glad to hear you are satisfied with the experience so far. The pleasure is ours to work with your team :)

Jacob C.

CEO & Co-Founder

Small-Business (50 or fewer emp.)

10/7/2025

"Powerful visibility and compliance for third-party scripts"

4.5/5

What do you like best about cside?

It finally shows what’s actually happening in the browser. You can see every script, where it comes from, what it’s doing, and whether it’s compliant or risky. The setup is quick, the dashboard is clear, and the alerts make it easy to catch issues before they become problems. Review collected by and hosted on G2.com.

What do you dislike about cside?

Some parts of the interface still feel early, and it takes a bit to get used to how scripts are grouped and displayed. But once you understand the logic, it’s very powerful. Great onboarding and support to help you get the hang of it. Review collected by and hosted on G2.com.

What problems is cside solving and how is that benefiting you?

We use a lot of third-party scripts, and it’s hard to know what’s actually running on the client side. c/side gives us full visibility and helps us detect unexpected behavior before it turns into a security or compliance issue. It also makes it easier to prove that we’re monitoring and managing scripts properly, which saves a lot of time during audits. Review collected by and hosted on G2.com.

Joseph M.

Software Engineer

Small-Business (50 or fewer emp.)

7/21/2025

"Surprised more platforms don't have these features"

5/5

What do you like best about cside?

c/side tells me everything I need to know about a script, and proactively makes sure they are safe to show to the user - if not, they detect/block it and let me know. It's also really helpful to view the script history, so I can figure out what changed if a new version seems a little sketchy. It's really made me realize how big of a problem 3rd party script security is, and there are no other solutions I've tried that dives as deep as c/side. The team is super responsive if you need support for anything, and while I don't need PCI/DSS compliance, it's great to know they cover that as well. Review collected by and hosted on G2.com.

What do you dislike about cside?

As someone who's not super technical with how the web itself behaves, parts of how the dashboard worked (and how they explained certain concepts) was a little confusing, but reaching out to their team helped clear a lot of it up. I can tell the product is only going to keep getting better and easier to use from here. Review collected by and hosted on G2.com.

Response from Simon Wijckmans of cside

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Thanks for your review! We appreciate your kind words and I'll make sure to address the feedback you shared. We are updating the dashboard as we speak.

Yusuf B.

CTO

Small-Business (50 or fewer emp.)

6/10/2025

"Gives us needed visibility into client-side activity"

5/5

What do you like best about cside?

It helps us understand what third-party scripts are actually doing on our site, which used to be pretty opaque. Instead of relying on assumptions or manual checks, we can now see script behavior clearly, which has helped us spot issues we wouldn’t have caught otherwise. It’s also been helpful when coordinating with teams during incidents. Review collected by and hosted on G2.com.

What do you dislike about cside?

Some parts of the interface aren’t immediately intuitive. It took a bit of trial and error to get familiar with the different views and how to filter the data effectively. Also, it would be helpful to have more built-in guidance or examples for interpreting script behavior. Review collected by and hosted on G2.com.

Edgardo C.

Developer

Small-Business (50 or fewer emp.)

7/19/2025

"A must have if you use third party scripts"

5/5

What do you like best about cside?

I use so many third party scripts, analytic tools, support widgets, polyfills, animation libraries, cdns, any of these could go rogue and replace the legit content with a keylogger or worst. Cside will email me if that happens, none of them have gone rogue yet, but Cside even warns me and shows me insights when a script changes their behavior. Such a great tool, very easy to use and simple set up on my react app, I check the dashboard every few weeks and always find something interesting about my scripts. Review collected by and hosted on G2.com.

What do you dislike about cside?

Understanding how the proxy prefixing works and how to prevent double fetch is tricky but once you understand what is going on it's alright. Besides that, I noticed some of my scripts were using timestamp in the URL for cache busting and it flood my dashboard with entries. I changed some of those scripts and used their pattern matching feature in others. Review collected by and hosted on G2.com.

Mark D.

CEO

Information Technology and Services

Small-Business (50 or fewer emp.)

6/6/2025

"Highly Recommended for PCI and more"

5/5

What do you like best about cside?

We have tried multiple products in the same space, but unfortunately, almost all of them turned out to be just compliance checkboxes, offering little to no real value. We did a POC with c/side for PCI compliance, and within the first week, our team started seeing real value. The dashboard had a good UI/UX and was easy to navigate. The way the product works made a lot of sense and helped us improve our security posture. We would definitely recommend the product for PCI and more. The detection capabilities we got with C/Side were unlike anything we saw in other products we tested in the past. Review collected by and hosted on G2.com.

What do you dislike about cside?

Not much to add in this section, we really like the product. We are excited to see what new features they bring in the future. They have already innovated in client-side attack detection, and we’d love to see the same disruptive approach continue. Review collected by and hosted on G2.com.

Verified User in Information Technology and Services

Small-Business (50 or fewer emp.)

7/28/2025

"Solid product. Works well. Great support"

5/5

What do you like best about cside?

Product is great. Onboarding was super easy. After registering I learned a lot about our website and potential threats with foreign scripts. Support is also very helpful—the folks respond very diligently and help as much as they can. Review collected by and hosted on G2.com.

What do you dislike about cside?

It’s clear that they’re still growing, so one of my qualms is that there are a lot of moving parts… The interface changes here and there but overall it’s pretty manageable. Review collected by and hosted on G2.com.

Verified User in Information Technology and Services

Small-Business (50 or fewer emp.)

6/26/2025

"Improved speed and transparency for client side JavaScript."

5/5

What do you like best about cside?

Third-party party client-side scripts often go unchecked and are a target for malicious actors. c/side puts you back in control of your web properties ensuring that third-party scripts behave as expected and are free from vulnerabilities. It's super quick to implement and once you've done that, you are able to keep tabs on all the changes to your scripts quite easily. Review collected by and hosted on G2.com.

What do you dislike about cside?

Honestly, there’s not much to dislike about c/side — it’s reliable and thoughtfully designed. I’m eager to see even more advanced customization options as the product continues to grow. The team has been responsive to feedback and quick to ship improvements, which gives me confidence in the roadmap ahead. Review collected by and hosted on G2.com.

Verified User in Consulting

Small-Business (50 or fewer emp.)

4/1/2025

"Client-Side Security Has Never Been More Secure"

4.5/5

What do you like best about cside?

With c/side, we now have a way to protect our clients/customers from potential cyber threats that are often overlooked by traditional cybersecurity measures. Review collected by and hosted on G2.com.

What do you dislike about cside?

It can sometimes introduce minimal latency. Review collected by and hosted on G2.com.

Recommendations to others considering cside:

If your website is a high-value target for browser supply chain attacks (e.g., finance, healthcare, e-commerce, SaaS), c/side offers a proactive security layer that could significantly reduce risk. Review collected by and hosted on G2.com.

What problems is cside solving and how is that benefiting you?

Traditionally, cybersecurity is focused in protecting the servers. c/side is a cybersecurity startup with expertise in third-party web script monitoring, optimization, and security—a field frequently neglected but absolutely vital. Third-party scripts are essential to the functionality of websites, supporting analytics, chatbots, and error handling, among other features. Yet they frequently update without a business's awareness, creating tremendous security threats. Malicious entities can take advantage of vulnerabilities within these scripts to reroute website visitors, harvest sensitive data, or alter website content. Review collected by and hosted on G2.com.