# OneTrust vs Didomi: cookie banner speed and features

On desktop, Didomi showed its banner sooner (498 ms vs 672 ms) but transferred 253 KB more than a page without a consent manager, against 211 KB for OneTrust. Neither added a measurable delay to the main content on desktop. On emulated mobile, Didomi added 1.29 s before the main content appeared and OneTrust 692 ms. Didomi’s was the largest delay on Next.js in this run.

We measured both in the same run, in a Next.js app. We measured each against the same page without a consent manager. They also share Script tag, React, Nuxt, Astro, TanStack Start integrations.

## Which is faster on desktop?

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

| Question | OneTrust | Didomi | Difference |
| --- | --- | --- | --- |
| How fast does the banner appear? | 629 ms | 466 ms | Didomi’s banner appeared 164 ms sooner. |
| Does it slow the page down? | No measurable change | No measurable change | Neither added a measurable delay. |
| How fast does a click respond? | 24 ms | 16 ms | About the same. They are less than 16 ms apart. |
| Does it block trackers until consent? | 4 of 4 checks passed | 4 of 4 checks passed | Both held trackers back in every check. |
| How much does it add to the page? | +211 KB (95% interval: 211 KB) | +253 KB (95% interval: 253 KB) | OneTrust added 42 KB less to the first load. |

## Which is faster on mobile?

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

On emulated mobile, OneTrust and Didomi showed their banners in about the same time. The medians were 3.92 s for OneTrust and 4.41 s for Didomi. OneTrust delayed the main content 804 ms less. Both held trackers back in every check. Their documented features are the same in this comparison.

| Question | OneTrust | Didomi | Difference |
| --- | --- | --- | --- |
| How fast does the banner appear? | 3.92 s | 4.41 s | About the same. The gap is under 20%, within run-to-run noise. |
| Does it slow the page down? | +476 ms (95% interval 444 ms to 508 ms) | +1.28 s (95% interval 1.26 s to 1.29 s) | OneTrust delayed the main content 804 ms less. |
| How fast does a click respond? | 16 ms | 16 ms | About the same. They are less than 16 ms apart. |
| Does it block trackers until consent? | 4 of 4 checks passed | 4 of 4 checks passed | Both held trackers back in every check. |
| How much does it add to the page? | +211 KB (95% interval: 211 KB) | +253 KB (95% interval: 253 KB) | OneTrust added 42 KB less to the first load. |

## Which features differ?

| Feature | OneTrust | Didomi |
| --- | --- | --- |
| IAB TCF | Per vendor docs (TCF v2.2 and v2.3) | Per vendor docs (TCF v2.2) |
| IAB GPP | Per vendor docs | Per vendor docs |
| Google Consent Mode v2 | Per vendor docs | Per vendor docs |
| Google-certified CMP | Per vendor docs | Per vendor docs |
| Global Privacy Control | Per vendor docs | Per vendor docs |
| Geo-targeted banners | Per vendor docs | Per vendor docs |
| Script blocking | Per vendor docs | Per vendor docs (Tag-based) |
| Consent records | Per vendor docs | Per vendor docs |
| Cookie scanning | Per vendor docs | Per vendor docs |
| Open source | Not supported (Proprietary) | Not supported (Proprietary) |
| Self-hostable | Partial (Script only; hosted backend) | Partial (Assets through your domain) |
| Headless UI | Partial (Mobile and CTV only) | Per vendor docs |
| TypeScript types | Unknown | Partial (React SDK only) |
| Free tier | Not supported (Quote-based pricing) | Not supported (Contact sales) |
| Script tag | Per vendor docs | Per vendor docs |
| React SDK | Not supported (Script tag only) | Per vendor docs (First-party SDK) |
| Next.js SDK | Not supported (Script tag only) | Not supported (Script tag only) |
| Vue SDK | Not supported (Script tag only) | Not supported (Script tag only) |
| Nuxt SDK | Not supported (Script tag only) | Not supported (Script tag only) |
| Svelte SDK | Not supported (Script tag only) | Not supported (Script tag only) |
| SvelteKit SDK | Not supported (Script tag only) | Not supported (Script tag only) |
| Astro SDK | Not supported (Script tag only) | Not supported (Script tag only) |
| TanStack Start SDK | Not supported (Script tag only) | Not supported (Script tag only) |

## Which should you choose?

### Choose OneTrust if

- Your privacy team already runs other OneTrust modules
- Mobile load time on slow phones is a priority

### Choose Didomi if

- You want a dedicated consent and preference platform
- Desktop banner speed matters more than page weight

## Questions about this pair

### Is OneTrust slower than Didomi?

On the desktop profile, Didomi’s banner appeared in a median 466 ms and OneTrust’s in 629 ms. Neither added a measurable delay.

### Do OneTrust and Didomi both support IAB TCF?

Both document it. Statuses come from vendor docs.

### Do OneTrust and Didomi block trackers before consent?

Both held trackers back in every check. Each check loads the page. Then it looks for trackers that ran, cookies that the page set or data that left the page before the visitor chose.

## Related comparisons

- [c15t vs OneTrust](https://cookiebench.com/compare/c15t-vs-onetrust.md)
- [c15t vs Didomi](https://cookiebench.com/compare/c15t-vs-didomi.md)
- [CookieYes vs OneTrust](https://cookiebench.com/compare/cookieyes-vs-onetrust.md)
- [OneTrust vs Usercentrics](https://cookiebench.com/compare/onetrust-vs-usercentrics.md)
- [Osano vs OneTrust](https://cookiebench.com/compare/osano-vs-onetrust.md)
- [Didomi vs Usercentrics](https://cookiebench.com/compare/didomi-vs-usercentrics.md)

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".