Operate
Serving modes
Every domain is in one of three modes. The mode decides whether Wrenda changes what crawlers receive, only records what it would have done, or steps aside entirely.
The three modes
| Mode | What crawlers get | Rules | Header | Request log |
|---|---|---|---|---|
| Active | The action your rule chose: optimized, pre-rendered, passed through or blocked | Evaluated and applied | none extra | action taken, cache hit/miss |
| Shadow | Always the original page (pass-through) | Evaluated and logged, never applied | X-Wrenda-Mode: shadow | action pass-through, plus the intended action the rule would have taken |
| Paused | Always the original page (pass-through) | Skipped entirely | X-Wrenda-Mode: paused | action pass-through, no intended action |
Changing the mode from the domain card takes effect within seconds — the API clears the edge's cached domain configuration on every change rather than waiting for its five-minute refresh.
Active
The normal state. Requests are matched against your crawler rules; AI crawlers get the optimized copy, search engines get the pre-rendered copy where you have a pre-render rule, humans pass through. Optimize and pre-render responses are cached (1 hour and 24 hours by default), so only the first request for a URL does real work. See Bot handling and Cache.
Shadow
New domains start in Shadow mode (the wizard's “Start in shadow mode” toggle, on by default). Wrenda sits in the traffic path and runs the full rule evaluation for every request, but serves the original origin response no matter what the rule says. Nothing any crawler sees changes.
Use Shadow mode to answer three questions before going live:
- Is traffic actually flowing through Wrenda? The
X-Wrenda-Mode: shadowheader and the request log prove it. - Do my rules match the crawlers I expect? Each logged request records the intended action — optimize, pre-render or block — so you can spot a rule that would block Googlebot before it does.
- Does the origin behave behind a proxy? Host-header 404s, redirect loops and certificate problems all show up here at zero risk.
Because every Shadow response is a pass-through, Shadow requests are not billable and nothing is written to the optimize or pre-render caches. Shadow domains are also skipped by sitemap watch (there is nothing to purge).
curl -I -H "User-Agent: GPTBot/1.0" "https://your-domain.com/"
# HTTP/2 200
# X-Wrenda-Mode: shadow
# X-Crawler-Action: pass-through
# X-Correlation-ID: …- The domain is Verified and Integration Health is healthy.
- Analytics show crawler requests with the intended actions you want (and no search engine with an intended block).
- Bot Testing returns a sensible optimized page for GPTBot and a fully rendered page for Googlebot.
Paused — the kill switch
Paused passes everything through and skips rule evaluation altogether. It exists for the moment you need Wrenda out of the way immediately — a bad rule, an origin incident you are debugging, a launch freeze — without touching DNS. The dashboard asks you to confirm before pausing. Traffic continues to flow through Wrenda's edge (DNS is unchanged), so latency is unaffected and un-pausing is instant.
Which mode when
| Situation | Mode |
|---|---|
| Just installed; DNS propagating | Shadow |
| Adding or editing rules on a live site | Keep Active; test the rule in Bot Testing first, or drop to Shadow for an hour |
| Origin migration / platform change | Shadow until the new origin passes the health check, then Active |
| Suspected problem caused by optimized content | Paused, then inspect the request log and Bot Testing |
| Normal operation | Active |
Setup checklist
The domain's Setup completeness card has a Mode active step. It stays open while the domain is in Shadow or Paused, with a one-click action to switch.