Snowfence vs CASB and secure web gateways
A cloud access security broker (CASB) or secure web gateway sees where a company’s traffic goes, and can allow or block whole services. Snowfence sees what happens on the laptop or server before the traffic leaves: which process read what, which AI tool is sending, and what the AI model asked it to do. The two answer different questions.
What do a CASB and a secure web gateway do?
Both sit between a company’s devices and the internet, usually in the cloud. A secure web gateway filters web traffic: it can block a site, or a category of sites, for everyone. A CASB adds control over cloud services: which apps people may use, which accounts, and sometimes what may be uploaded to them. Many companies buy both together as part of a security service edge (SSE).
They are good at the network view: this device tried to reach this service, and the rules said yes or no.
What can’t a network gateway see?
A gateway sees traffic after it has left the device. By then it has lost three things.
- Which process sent it. The gateway sees the laptop, not whether the request came from a person typing in a browser or from a coding agent that read the SSH keys a minute earlier.
- What was read before. It can’t link an upload to the sensitive file that was opened just before, so it judges every send on its own.
- What the model asked for. When an AI model tells an agent to run a command or call a tool, that instruction arrives in the model’s reply. A gateway that doesn’t follow the conversation can’t cancel it before the agent acts.
Gateways also work best when they can tell AI traffic apart. New AI tools, and agents that call model services directly from the command line, can look like any other encrypted connection.
How Snowfence is different
| CASB or secure web gateway | Snowfence | |
|---|---|---|
| Where it runs | In the network, between devices and the internet | On each laptop and server, plus a gateway in your own environment |
| Sees | Destinations, and some content | Destinations, prompts to AI services, file reads, programs started, MCP calls, pastes and uploads |
| Knows which process sent it | No | Yes |
| Links read to send | No | Yes: whatever read sensitive data may only send it to places approved for that data |
| Checks what the AI asked for | No | Yes: dangerous tool calls are cancelled before the agent runs them |
| Personal vs company AI accounts | Sometimes, by tenant controls | Yes, and rules can differ by account: customer data may go to the company workspace but not a personal one |
Do you need both?
Often, yes. A gateway protects every kind of traffic from every kind of device. Snowfence protects the AI tools on company laptops and servers in much more depth. Snowfence also uses the network as one of its checks: a browser without a working Snowfence extension can’t reach AI sites, and company AI services can accept sign-ins only from laptops that prove Snowfence is running.
What Snowfence can’t stop
Snowfence covers company laptops, and servers that run it or send their AI calls through its gateway. It can’t see personal devices, a photo of the screen, or agents running entirely in a vendor’s cloud. The security page lists every limit.
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