# The best Next.js cookie bar > It's Inth and c15t, it's fast, it's open source, it's everything we could have dreamed of and more. Here's the best cookie bar for Next.js. **Published:** 2025-07-18 | **Updated:** 2026-08-11 | **Categories:** Tutorials Watch: https://www.youtube.com/watch?v=Pot1e5CRtR4 --- ## Transcript Hey folks, how's it going? I want to do this video today because I really want to talk about this thing, uh, just over here. This is, uh, C-15T, and more specifically it's C-15T hosted on consent.io. Um, it's an incredible cookie bar. Um, I don't think most people know it even exists. I didn't know it existed, and I am so stoked to actually talk about it. Um, so one of the first things that you'll notice is this is styled perfectly like the rest of the Robboto Studio website. It's fully, fully customizable. We're using Tailwind CSS to style this, but you can do whatever you want. If you want to use styled components, if you want to use Tailwind, whatever it is, it works great. Soon as you see, uh, this load up, I'll show you how fast this thing is, by the way. So just with a refresh, obviously you probably want to do a full refresh. So feel free to go visit the website and see for yourself. Um, but you can see it's ludicrously fast. It loads up in like 100 milliseconds. Um, talking about that, there is a website called cookiebench.com which tells you the best performing cookies and the worst performing cookies, which is the ones that we always have to implement and it drives us crazy because you hate going from like a 100 out of 100 on a performance score to dropping down to, like, literally in some cases, you know, 80, 70, just from the cookie banner. So really, really cool tool. Um, so again, the hosting side of this is consent. Feel free to have a look over there. Look at that beautiful logo on the bottom as well. Um, but they're using, you can see how well they've actually customized this themselves. Totally different from what we're using. Um, and again, C-15T, this is the coolest bit if you want my honest opinion. Um, the entire setup for our website was literally step one. We didn't need to do database migrations. We literally ran this tool and it did everything. The only thing that caught us out when we were building was we forgot to put the environmental variable in, which is, you know, everybody does it. Schoolboy error. But we're using PMP. So feel free to use this with Turbo Start Sanity, Turbo Start Contempt, whatever tool you want to use. Obviously, they're the best tools, but feel free. Um, I just want to tell people about it. It's awesome. I haven't been sponsored to say this. I love it. Take care. Have a great day. ## Frequently asked questions ### What is c15t? c15t is an open-source cookie consent and banner library for modern web apps. It ships with sensible styling defaults but is fully customisable, so you can use Tailwind, styled-components, or your own setup. Inth (https://inth.com/) is the hosted version of c15t, which is the easiest way to use it in production. ### What is the best cookie banner for Next.js? c15t hosted on Inth is the recommendation here. It's open source, loads in roughly 100ms, integrates as a single setup step (no database migrations), and matches whatever styling system your Next.js app already uses. Performance is what sets it apart: most cookie banners noticeably tank Lighthouse scores, and this one barely moves the needle. ### What is Inth? Inth (https://inth.com/) is the hosted product behind the c15t open-source library, previously known as consent.io. You get the same banner and consent flow without running the back end yourself. Connect it to your Next.js (or other) app, drop in an environment variable, and the banner is live. The styling is fully customisable so it doesn't look like an off-the-shelf widget. ### Is c15t open source? Yes. c15t is open source, and Inth is the hosted commercial offering built on top of it. You can self-host the open-source library or pay for the managed version, depending on whether you want to run the consent storage and dashboard yourself. ### How fast is the c15t cookie banner? Around 100 milliseconds to render, based on the demo in the video. That matters because most cookie banners are responsible for noticeable performance drops; going from a Lighthouse score of 100 to 70-80 just because of the banner is common. c15t is designed to avoid that, which is why cookiebench.com is a useful place to compare options. ### How do you add a cookie banner to a Next.js app? With c15t and Inth it's a single install step plus an environment variable. There are no database migrations to run, and the library works out of the box with Tailwind, styled-components, or whatever else your project uses. The hardest part is remembering to set the environment variable, which is the one thing that tripped Roboto Studio up during their setup. ### Does c15t handle GDPR? Yes. c15t is designed around modern consent requirements (GDPR, CCPA), and Inth stores the consent records on your behalf if you want a managed setup. You still need a cookie policy on your site, but the banner, opt-in/opt-out flow, and consent storage are what c15t handles for you.