Nullgen AI BlockerHow to block Synthesia
How to block Synthesia on every device
Synthesia generates AI presenter videos from a script, used for training and marketing content. Below: how to block Synthesia in the browser, on phones and tablets, on your home or school network, and on managed devices.
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Chrome
Edge
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Synthesia
AI video generators
synthesia.ioBlocked1 hostname in the Nullgen catalog
Every entry also covers its subdomains, so the Synthesia app and API are blocked too.
What Synthesia connects to
These are the hostnames Synthesia uses for its website, its apps, and its API. Each entry is matched as a suffix — blocking synthesia.io also blocks every subdomain of it — so the Synthesia app cannot slip through on a hostname that is not listed. Shared hosts that other products need are deliberately left out.
| Hostname | Role |
|---|---|
| synthesia.io | Main website |
Block Synthesia in the browser
Free: the Nullgen browser extension
The free extension blocks Synthesia and every other tool in the catalog in Chrome, Edge, Firefox, and Safari. It works on the page itself — no DNS change, no policy — and updates as the catalog grows.
Managed browsers: block the sites by policy
On a school or company fleet, push the hostnames as a browser policy so Synthesia is blocked even when someone uninstalls extensions. These snippets use the official Chrome, Edge, and Firefox policy names and the same hosts listed above.
Chrome and Edge — URLBlocklist
{
"URLBlocklist": [
"synthesia.io"
]
}Firefox — policies.json
{
"policies": {
"WebsiteFilter": {
"Block": [
"*://synthesia.io/*",
"*://*.synthesia.io/*"
]
}
}
}Chrome and Edge treat a bare hostname as the host plus every subdomain. Firefox needs both the apex and the wildcard pattern.
Need every AI tool in one file, or a .reg or macOS profile?
Open the free policy generatorBlock the Synthesia app on phones and tablets
Nullgen mobile app
The Nullgen app blocks Synthesia and 100+ other AI apps and sites on the whole device with an on-device filter — the app, the website, and the API, on any network, with no DNS server to run. Included with Nullgen Pro.
Without Nullgen: Screen Time on iPhone and iPad
- 1Open Settings → Screen Time → Content & Privacy Restrictions and turn restrictions on. This covers Synthesia in Safari and in apps that use Apple’s web filter.
- 2Under Web Content, choose Limit Adult Websites — the setting that lets you deny synthesia.io by name.
- 3Under Never Allow, add synthesia.io. Safari and apps that use Apple’s web filter will refuse it.
- 4To keep the Synthesia app off the device entirely, delete it and set Installing Apps to Don’t Allow, or use Ask to Buy on a child’s Apple Account.
Without Nullgen: Family Link on Android
- 1Open Family Link, choose the child, then Controls → Content restrictions → Google Chrome — where Synthesia can be blocked by site.
- 2Choose Only allow approved sites, or add synthesia.io under Blocked sites.
- 3Under Controls → App limits, block the Synthesia app, or require approval for new installs from Google Play.
Block Synthesia on your home or school network
A DNS blocker such as Pi-hole, AdGuard Home, NextDNS, or pfBlockerNG blocks Synthesia for every device on the network — laptops, phones, consoles, and the Synthesia app — without installing anything on them. Subscribe to the Synthesia file from the public blocklist, or paste the rules directly.
Subscribe to the Synthesia list
AdGuard Home, uBlock Origin, and Brave rules
||synthesia.io^DNS blocking cannot see inside a VPN or a phone on mobile data. For a block that follows the device, use the Nullgen apps or an MDM profile.
Block Synthesia on managed devices
Schools and companies can block Synthesia on every managed iPhone, iPad, laptop, and Chromebook from the MDM they already run — Intune, Jamf, Kandji, or Google Workspace — with per-person policies and an approval flow for legitimate use. Nullgen Pro provides the profiles and the dashboard; these guides walk through the setup.
Questions about blocking Synthesia
Does the free Nullgen extension block Synthesia?
Yes. The free extension blocks prompts on Synthesia and every other AI tool in the catalog in Chrome, Edge, Firefox, and Safari. It works on the page itself, so it needs no policy and no DNS change.
Will blocking Synthesia break other websites?
No. Every hostname on this page belongs to Synthesia alone. Shared websites that other products depend on are never on the list — which is also why AI features built into those products stay reachable.
Can someone get around a Synthesia block?
A browser-only block can be bypassed with another browser or the Synthesia app, and a network block can be bypassed with a VPN or a phone on mobile data. A block on the device itself — the Nullgen apps, Screen Time, or an MDM profile — follows the device wherever it goes.
Does this block the Synthesia app, not just the website?
A DNS or device-level block does. The app talks to the same hostnames listed above, and every entry covers its subdomains, so the app cannot slip through on a hostname that is not listed. A browser policy or extension only covers the browser.
What happens when Synthesia adds a new hostname?
The catalog is updated as vendors change, and the Nullgen apps, the extension, and the public blocklist all read from it, so a new hostname reaches every device without anyone editing a list by hand.
Block Synthesia today
Start with the free browser extension. Add Nullgen Pro when you need the Synthesia app blocked on phones, tablets, and desktops, with approvals for the people who really need it.