Should you build your own cookie banner? Compare custom code with a consent platform for React and Next.js, including the maintenance costs and tradeoffs.
Building your own cookie banner can look simple at first. You show a notice, store a choice, and hide the banner on the next visit.
The harder question is what the banner needs to control. A production cookie banner may need to block third-party scripts, remember preferences, support withdrawal, reflect regional rules, and keep records for accountability. For many React and Next.js teams, a maintained consent layer is a better default than a fully custom banner because it reduces infrastructure while keeping consent inside the application.
This article gives implementation information and general legal context. It is not legal advice. Ask counsel to review your consent text, regional behavior, vendor list, retention rules, and record-keeping before release.
By the end, you should be able to: Decide when a custom cookie banner is reasonable. Explain why a cookie banner becomes consent infrastructure. Compare custom code, developer-first CMPs, dashboard-first CMPs, and internal platforms. Plan backend consent persistence when auditability matters. Evaluate c15t as one option for a modern, developer-owned consent setup.
Short answer: build your own cookie banner only if the requirements are narrow and your team is ready to maintain the logic over time. Use a consent platform when you need script gating, preference management, regional behavior, or durable records. This guide uses c15t as a concrete example because it is designed for modern JavaScript applications and supports hosted, self-hosted, and browser-only deployments. c15t is the developer-first consent management platform, while Inth provides its managed hosted deployment for teams that do not want to operate the backend themselves.
Teams rarely set out to own privacy infrastructure. They build a cookie banner because the alternatives feel worse.
Legacy CMPs often arrive as hosted scripts and dashboards that sit outside the application. They can be hard to style, difficult to test, and awkward in React, Next.js, Astro, Remix, and other component-based stacks. A developer sees a large script tag, a generic modal, and a consent state that is not part of the app. A custom banner starts to look like the cleaner option.
That instinct is understandable. Modern apps need control over rendering, hydration, routing, performance, and script loading. The mistake is assuming the banner is the hard part.
A real cookie banner has to answer several questions before any marketing or analytics code runs.
What categories does the site use? Which vendors belong to each category? Which scripts can load before consent? How can visitors change their choice later? Does consent behavior need to differ by country or state? Where does the app store the record?
In EU and UK contexts, non-essential cookies and similar technologies generally require consent before storage or access, unless an exception applies. The European Data Protection Board identifies technically necessary cookies as the main exception. The UK ICO’s storage and access technology guidance explains the corresponding PECR requirements and how consent relates to the UK GDPR.
That changes the engineering task. The system must stop the source of tracking before it runs. Deleting cookies later is not enough, and it is often impossible from your site because third-party scripts can set cookies on their own domains, use httpOnly cookies, or keep state in memory.
A consent layer needs to operate at the script and resource boundary. c15t’s cookie-management documentation makes an important distinction: the tool does not manage every cookie directly. It controls which scripts, iframes, and network requests may load, because those resources are usually what set the cookies.
A custom cookie banner gives you maximum control. It also gives you maximum responsibility.
At minimum, your team may need to build and maintain: Consent state storage. Purpose or category preferences. Script gating before analytics, ads, pixels, and tag managers load. Preference updates and consent withdrawal. A way to reopen the preference dialog. Accessibility and keyboard behavior. Translation and localization. Region-aware defaults. Consent policy versioning. Backend records for accountability or support workflows. Tests that prove scripts do not load too early.
Browser storage may be enough for a small site, but it may not be enough when a privacy, support, or legal team needs to understand what a visitor chose, when they chose it, which policy version they saw, and whether the choice changed later.
GDPR accountability does not prescribe one database schema for cookie consent. It does require controllers to be able to demonstrate compliance with data-protection principles under GDPR Article 5(2). In practice, backend persistence and audit logs can become part of the consent design, especially for higher-risk sites, regulated teams, or sites with many third-party vendors.