# c15t cookie banner: speed and features on TanStack Start

Open-source consent manager with framework SDKs and a self-hostable backend.

- Vendor: inth
- Website: https://c15t.com
- Version tested: 3.0.0-alpha.10
- Framework: TanStack Start

We measured other CMPs on Next.js only, so on TanStack Start this comparison uses c15t’s other integrations. [c15t on Next.js](https://cookiebench.com/benchmarks/c15t.md).

## Desktop

Desktop profile: 1365 × 768 · No CPU slowdown · 12.5 MB/s, no added latency.

In our tests with its TanStack Start integration, c15t showed its cookie banner in a median 54 ms on desktop. It delayed the main content by 24 ms (95% interval 8 ms to 44 ms). Accept responded in 16 ms and Reject in 16 ms. It held trackers back in all 4 consent checks.

On an emulated mid-tier phone, the banner took 250 ms. Per vendor docs, c15t supports IAB TCF, IAB GPP, Google Consent Mode v2 and Global Privacy Control, but not Google CMP certification.

| Question | Answer | How it compares | Context |
| --- | --- | --- | --- |
| How fast does the banner appear? | 54 ms | 3rd fastest of 6 c15t integrations | Median of 15 visits. |
| Does it slow the page down? | +24 ms (95% interval 8 ms to 44 ms) | 3rd of 6 c15t integrations, from least to most delay | Compared with the same page without a consent manager. |
| How fast does a click respond? | 16 ms | Joint fastest of 6 c15t integrations | Reject responded in 16 ms. Under 200 ms feels instant. |
| Does it block trackers until consent? | 4 of 4 checks passed | All 6 c15t integrations passed every check | No tracker ran and the page set no cookie before the visitor chose. |

### Known issues on desktop

- c15t makes this route render per request, while the no-CMP page is prerendered. That accounts for most of its added TTFB and FCP.

## Mobile

Mobile (emulated) profile: 390 × 844, DPR 3 · Mid-tier phone CPU (4× slowdown) · 200 KB/s, 150 ms latency.

In our tests with its TanStack Start integration, c15t showed its cookie banner in a median 250 ms on an emulated mid-tier phone. It delayed the main content by 416 ms (95% interval 408 ms to 436 ms). Accept responded in 48 ms and Reject in 32 ms. It held trackers back in all 4 consent checks.

On desktop, the banner took 54 ms. Per vendor docs, c15t supports IAB TCF, IAB GPP, Google Consent Mode v2 and Global Privacy Control, but not Google CMP certification.

| Question | Answer | How it compares | Context |
| --- | --- | --- | --- |
| How fast does the banner appear? | 250 ms | 3rd fastest of 6 c15t integrations | Median of 15 visits. |
| Does it slow the page down? | +416 ms (95% interval 408 ms to 436 ms) | 3rd of 6 c15t integrations, from least to most delay | Compared with the same page without a consent manager. |
| How fast does a click respond? | 48 ms | 6th fastest of 6 c15t integrations | Reject responded in 32 ms. Under 200 ms feels instant. |
| Does it block trackers until consent? | 4 of 4 checks passed | All 6 c15t integrations passed every check | No tracker ran and the page set no cookie before the visitor chose. |

### Known issues on mobile

- c15t makes this route render per request, while the no-CMP page is prerendered. That accounts for most of its added TTFB and FCP.

## Which standards and features does c15t support?

### Standards

| Feature | Support | Source |
| --- | --- | --- |
| IAB TCF | Per vendor docs | https://v3.c15t.com/docs/frameworks/next/iab |
| IAB GPP | Per vendor docs (GPP 1.1) | https://v3.c15t.com/docs/frameworks/next/gpp |
| Google Consent Mode v2 | Per vendor docs | https://v3.c15t.com/docs/integrations/google-tag |
| Google-certified CMP | Not supported (Not on Google’s list) | https://support.google.com/adsense/answer/13554116 |
| Global Privacy Control | Per vendor docs | https://v3.c15t.com/docs/frameworks/next/geography-headers |

### Compliance

| Feature | Support | Source |
| --- | --- | --- |
| Geo-targeted banners | Per vendor docs | https://v3.c15t.com/docs/self-host/guides/policy-packs |
| Script blocking | Per vendor docs | https://v3.c15t.com/docs/frameworks/next/network-blocker |
| Consent records | Per vendor docs (With a backend) | https://v3.c15t.com/docs/self-host/overview |
| Cookie scanning | Per vendor docs (Via Inth Website Audit) | https://inth.com/website-audit |

### Developer

| Feature | Support | Source |
| --- | --- | --- |
| Open source | Per vendor docs (Apache-2.0) | https://v3.c15t.com/docs/oss/license |
| Self-hostable | Per vendor docs | https://v3.c15t.com/docs/self-host/overview |
| Headless UI | Per vendor docs | https://v3.c15t.com/docs/frameworks/next/headless |
| TypeScript types | Per vendor docs | https://www.npmjs.com/package/c15t |

### Pricing

| Feature | Support | Source |
| --- | --- | --- |
| Free tier | Per vendor docs (Open source; hosted free plan) | https://inth.com/pricing |

## Which frameworks does c15t work with?

c15t has first-party SDKs for 8 frameworks. Elsewhere it installs through a script tag. This run measured 6 integrations, each against the same app without a consent manager. The results at the top start on Next.js, the framework that we tested every CMP on. The Framework menu switches them. Vue, Svelte and SvelteKit have SDKs but no benchmark fixture yet.

| Framework | Integration | Benchmarked |
| --- | --- | --- |
| Script tag | Script tag | [Yes](https://cookiebench.com/benchmarks/c15t/script-tag.md) |
| React | First-party SDK | [Yes](https://cookiebench.com/benchmarks/c15t/react.md) |
| Next.js | First-party SDK | [Yes](https://cookiebench.com/benchmarks/c15t.md) |
| Vue | First-party SDK | No |
| Nuxt | First-party SDK | [Yes](https://cookiebench.com/benchmarks/c15t/nuxt.md) |
| Svelte | First-party SDK | No |
| SvelteKit | First-party SDK | No |
| Astro | First-party SDK | [Yes](https://cookiebench.com/benchmarks/c15t/astro.md) |
| TanStack Start | First-party SDK | Yes (this page) |

## How does c15t compare?

- [c15t vs OneTrust](https://cookiebench.com/compare/c15t-vs-onetrust.md): On desktop, c15t showed its banner in a median 65 ms, against 672 ms for OneTrust.
- [c15t vs Didomi](https://cookiebench.com/compare/c15t-vs-didomi.md): Side-by-side results from the same run.
- [c15t vs Cookie Control](https://cookiebench.com/compare/c15t-vs-cookie-control.md): Side-by-side results from the same run.
- [c15t vs Enzuzo](https://cookiebench.com/compare/c15t-vs-enzuzo.md): Side-by-side results from the same run.
- [c15t vs iubenda](https://cookiebench.com/compare/c15t-vs-iubenda.md): Side-by-side results from the same run.
- [c15t vs Ketch](https://cookiebench.com/compare/c15t-vs-ketch.md): Side-by-side results from the same run.
- [c15t vs Osano](https://cookiebench.com/compare/c15t-vs-osano.md): Side-by-side results from the same run.
- [c15t vs CookieYes](https://cookiebench.com/compare/c15t-vs-cookieyes.md): Side-by-side results from the same run.
- [c15t vs Usercentrics](https://cookiebench.com/compare/c15t-vs-usercentrics.md): Side-by-side results from the same run.

## Questions about c15t

### How fast is c15t’s cookie banner?

On desktop, it appeared in a median 60 ms, against 471 ms for the median of the 10 CMPs measured. On an emulated mid-tier phone, it appeared in a median 240 ms, against 2.71 s for the median of the 10 CMPs measured.

### Does c15t slow down the page?

On desktop it delayed the main content by 16 ms (95% interval 8 ms to 40 ms). On an emulated mid-tier phone it delayed the main content by 408 ms (95% interval 396 ms to 420 ms). Delay is the extra time before the main content appears. We compare Largest Contentful Paint on the same page, with and without a consent manager.

### Does c15t block trackers before consent?

It passed 4 of 4 checks on desktop and on an emulated mid-tier phone. A check fails if a tracker runs, the page sets a cookie or data leaves the page before the visitor chooses.

### Does c15t support IAB TCF and IAB GPP?

Per vendor docs, c15t supports IAB TCF, IAB GPP, Google Consent Mode v2 and Global Privacy Control, but not Google CMP certification. Feature support comes from c15t’s documentation. CookieBench did not test these features itself.

Spotted a mistake? [Report a correction](https://cookiebench.com/corrections.md) and we will re-check it.

Methodology [cookiebench-v3.2.4](https://cookiebench.com/methodology). inth, the team behind c15t, maintains CookieBench. c15t is one of the consent managers we measure ([disclosure](https://cookiebench.com/methodology)). Feature support comes from vendor documentation unless a row says "Verified by test".