Rules

Rules change traffic as it passes through Plonix, in plain steps. Use them to send your bug bounty handle on every request, swap a token, strip Content-Security-Policy from responses, or flip a feature flag in a JSON response.

Rules here change traffic. To teach Plonix to recognise technologies, see Detection rules.

What a rule does#

• Add header: send a header on every request, such as X-Bug-Bounty: yourname.
• Change header: set a header to a new value.
• Remove header: leave a header out.
• Replace text in the request line, headers or body, or in the response headers or body. Match literal text or a regular expression; $1 puts back what a group matched.

Where it applies#

Each rule says which traffic it changes: traffic from your browser, requests you send from the Bench (and Bench runs and the Access check), and requests Scans send. A rule can be limited to in-scope hosts, and it can have a condition written as a Traffic search, such as host:api.example.com method:POST, so it only changes what matches.

The Rules screen#

The Rules screen lists every rule in plain words, with a switch per rule and one switch that pauses them all. + Add rule opens a short form with a preview of what every request will carry. Right-click any header in the Lens to start a rule from it, already filled in. A pill in the Traffic toolbar shows how many rules are on and pauses them in one click.

What you see afterwards#

Each exchange records which rules changed it and the request as it was. Traffic and the Lens mark it changed, and the Lens shows it as sent, as it was, or side by side.

Limits#

• Body rules apply to bodies within the body limit (Settings › Proxy › Keep bodies up to). Longer, streaming and event-stream bodies pass unchanged.
• Compressed response bodies are matched decoded and sent uncompressed when changed.
• WebSocket handshakes and messages are not changed.
• Agents cannot read or change rules.

From the terminal#

plonix replace header add X-Bug-Bounty me --bench --scans
plonix replace add request-header '(?i)^user-agent: .*$' 'User-Agent: plonix' --regex
plonix replace add response-body '"debug":false' '"debug":true' --in-scope
plonix replace                    # the rules in order; or: enable 2, disable 2, rm 2

The same rules are at /api/replace in the local API.