# Dvina's browser agent

> How website owners can recognize, verify, allow or block the browser Dvina uses for the people it works for.

Dvina's browser visits websites for one person at a time, when that person asks Dvina for something that takes a real browser. This page is for website owners: what the browser does, how to recognize its requests and how to allow or block it.

## What it is

Dvina is a personal assistant. When someone signed in to Dvina asks for a job that takes a website, like comparing offers or filling in a form they asked for, Dvina can do it in a browser of its own, on that person's Dvina computer. It's a desktop Chromium with a window, not a headless browser, and the person can watch it live and take it over at any time.

- **It acts for one person.** Each browser belongs to one signed-in Dvina user and works on what that person asked for.
- **It isn't a crawler.** There's no list of sites it visits on its own. It opens the pages a task needs, one step at a time: it loads a page, reads it, then acts on it, the way a person does.
- **Never used to train models.** What Dvina's browser reads on your site is used only for the request of the person it works for. It never trains an AI model.
- **It leaves the person's own decisions to them.** It doesn't type passwords or card details. When a page needs the person to sign in or pay, Dvina stops and asks them to take over. Personal details, sending, paying and deleting wait for the person's OK.
- **It doesn't solve human verification.** When it meets a check that a person is browsing, like Cloudflare's check, Turnstile, reCAPTCHA or hCaptcha, it doesn't click it, solve it or reload it. When a check clears by itself, Dvina waits for it. When it stays, the work stops, and the person takes over the browser, passes the check and hands it back.

## Recognize its requests

Dvina's browser signs every http and https request it sends with [Web Bot Auth](https://datatracker.ietf.org/wg/webbotauth/about/), HTTP message signatures ([RFC 9421](https://www.rfc-editor.org/rfc/rfc9421)) with an Ed25519 key. Each request carries three headers:

```http
Signature-Agent: "https://api.dvina.ai"
Signature-Input: sig1=("@authority" "signature-agent");created=<unix time>;expires=<created + 60>;keyid="<key id>";alg="ed25519";nonce="<random>";tag="web-bot-auth"
Signature: sig1=:<Ed25519 signature>:
```

- `Signature-Agent` names Dvina, the origin where its keys are published.
- `Signature-Input` covers the request's `@authority` (your host) and the `Signature-Agent` header. The `tag` is `web-bot-auth`.
- Each signature is valid for 60 seconds, from `created` to `expires`.
- `keyid` is the key's JWK thumbprint ([RFC 7638](https://www.rfc-editor.org/rfc/rfc7638)).

The browser sends Chromium's own user agent, the same as any Chromium on Linux, for example:

```text
Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/155.0.0.0 Safari/537.36
```

Its Chrome version moves with Chromium's updates, and the user agent says nothing about Dvina. Recognize Dvina by its signature, not its user agent.

> [!NOTE]
> With the desktop app, a person can also let Dvina use a browser on their own computer. That browser doesn't sign its requests and looks like the person's own browsing.

## Verify a signature

Dvina publishes its public key at its key directory:

```text
https://api.dvina.ai/.well-known/http-message-signatures-directory
```

The directory answers with `Content-Type: application/http-message-signatures-directory+json` and a JSON Web Key Set with Dvina's Ed25519 public key. The answer is signed with the same key, with `tag="http-message-signatures-directory"`.

If your site is on Cloudflare, Cloudflare verifies signed agents for you. To verify a request yourself:

1. Check that `Signature-Agent` is `"https://api.dvina.ai"` and that `Signature-Input` has `tag="web-bot-auth"`.
2. Check that the time now is between `created` and `expires`.
3. Get the key directory and pick the key whose JWK thumbprint matches `keyid`.
4. Build the signature base from `@authority`, `signature-agent` and the signature parameters, as RFC 9421 describes, and verify the `Signature` with that Ed25519 key.

Anyone can send these headers. Treat a request as Dvina's only when its signature verifies against Dvina's key directory.

## Allow or block it

Dvina's browser acts in real time for one person: the kind of traffic Cloudflare's **Agent** preset covers. If your site is on Cloudflare:

- **AI bot policies:** In **Security Settings**, choose **Configure AI bot policies**. For **Agent**, choose **Allow (do not block)**, **Block on pages with ads** or **Block (on all pages)**.
- **WAF custom rules:** Requests from verified bots and signed agents have `cf.client.bot` (`cf.bot_management.verified_bot` with Bot Management) set to true. Use it in a custom rule to skip, challenge or block them.
- **Verified bots directory:** See the agents Cloudflare verifies in [Cloudflare Radar](https://radar.cloudflare.com/verified-bots).

Anywhere else, verify the signature as described above, then allow or block requests whose verified `Signature-Agent` is `"https://api.dvina.ai"`.

## Contact us

Questions about Dvina's browser on your site, or a request that didn't behave as this page describes? Email [support@dvina.ai](mailto:support@dvina.ai) with your site's address and, if you have them, the time and the `keyid` of the requests.

## Related

- [Computer Use](/docs/use-dvina/features/computer-use)
- [Privacy and data](/docs/help/privacy-and-data)