c15t

Cookie banners usually arrive as a third-party snippet you cannot inspect, style, or version alongside the rest of your application. c15t moves consent management back into the codebase, giving JavaScript, React, and Next.js teams prebuilt banners, consent dialogs, and preference centers, plus headless APIs when the design calls for something custom.

The project ships as a set of npm packages: a framework-agnostic core, React and Next.js bindings with server component and SSR support, translations, a CLI for configuration and database migrations, and a self-hostable backend that stores durable consent records, policy state, and audit logs. A separate scripts package holds consent-aware loaders for dozens of analytics and marketing tools.

Several pieces cover the parts of consent that teams usually hand-roll.

• Consent gating: analytics, ads, pixels, tag managers, and chat widgets run only once matching consent exists.
• Google Consent Mode v2: Tag Manager and gtag.js get denied defaults at page start and updates when a user chooses.
• Prebuilt or headless: use the shipped UI components, React hooks, or framework-native primitives.
• IAB TCF 2.3: an addon generates TC strings and exposes vendor and purpose controls for programmatic advertising.
• Deployment modes: a hosted backend, a self-hosted backend, or offline mode storing consent in the browser.

Offline mode suits local development, previews, and static sites, while the self-hosted backend needs your own database and infrastructure. Teams already on Next.js will find the App Router and Pages Router integrations the shortest path in.