---
title: "Configuring U2F"
url: https://develop.sentry.dev/development-infrastructure/environment/u2f/
---

# Configuring U2F

You will need an HTTPS-accessible development server to enable u2f. The easiest way to achieve this is by using [ngrok](https://ngrok.com/).

We recommend persisting this server name so you can configure it once and use it repeatedly. To do this, open up `~/.ngrok2/ngrok.yml` and add a `sentry` instance:

```yaml
authtoken: REDACTED
tunnels:
  sentry:
    proto: http
    addr: 8000
    subdomain: myusername-somethingobscure
```

Now you can run `ngrok start sentry` to spin up the proxy.

Next up, map your persistent HTTPS url to your local Sentry server within Sentry's configuration. To do this open up `~/.sentry/sentry.conf.py` and add the following:

```python
# ... existing settings

import os

if os.environ.get("NGROK"):
    URL = "https://myusername-somethingobscure.ngrok.io"

    SENTRY_OPTIONS["u2f.facets"] = [URL]
    SENTRY_OPTIONS["system.url-prefix"] = URL
```

Note: We're using an optional `NGROK` environment variable here so you can easily opt-out of requiring the Ngrok server to be run.

Now you start your development server:

```shell
NGROK=1 sentry devserver
```