DuckAssistBot
DuckDuckGo's AI-assisted answers, crawled in real time
What DuckAssistBot does
DuckAssistBot crawls pages in real time for DuckDuckGo's AI-assisted answers. Real time is the part worth noticing: it is not building an index in advance and consulting it later, it is fetching when the answer needs your page.
DuckDuckGo is the clearest of any vendor here about what blocking costs. It states that opting out of DuckAssistBot does not affect organic search rankings and does not change whether your site appears in its search results. The AI surface and the search surface are genuinely separate, and it says so.
Its IP list is also the second largest in this directory at 486 prefixes, behind only Googlebot — which follows from real-time fetching happening wherever the request is served.
How to block DuckAssistBot
Add this to the robots.txt at the root of your domain, alongside what is already there rather than replacing it.
robots.txt
User-agent: DuckAssistBot
Disallow: /What that costs you: DuckAssist cannot quote you. DuckDuckGo states this does not affect your organic rankings either way.
To allow it instead, write nothing. A crawler with no group of its own follows your User-agent: * rules, and giving it a named group with Allow: / detaches it from those rules entirely — including any path you disallow there.
Find it in your logs
DuckDuckGo names the token but does not publish a full user-agent string for it, so match on the token itself.
To find every visit it has made, and the addresses it came from:
Terminal
grep -F 'DuckAssistBot' /var/log/nginx/access.log | awk '{print $1}' | sort | uniq -c | sort -rnCheck that it is really DuckAssistBot
A user agent is a string the visitor chooses, so on its own it proves nothing — anyone can send yours. DuckDuckGo publishes the addresses DuckAssistBot fetches from: 486 prefixes when we read the file, last changed on 1 September 2026. Take an address out of your logs and check it against that list.
Terminal
curl -s https://duckduckgo.com/duckassistbot.json | python3 -c "
import sys, json, ipaddress
addr = ipaddress.ip_address('203.0.113.10') # the address from your logs
nets = json.load(sys.stdin)['prefixes']
print(any(addr in ipaddress.ip_network(n.get('ipv4Prefix') or n['ipv6Prefix']) for n in nets))
"False means something else is wearing the name, and it is under no obligation to respect anything in your robots.txt. That is the traffic worth blocking at the edge, rather than the crawler that was asking politely.
What DuckDuckGo says about it
Changes take 72 hours
DuckDuckGo states that once you disallow the DuckAssistBot user agent, the change takes effect after 72 hours. That is the longest published propagation window of any vendor here, and worth knowing before you conclude a block did not work.
Rankings are unaffected
DuckDuckGo states plainly that opting out of DuckAssistBot does not impact organic search rankings and will not affect whether websites appear in its search results. Few vendors separate the two questions this explicitly.
Read from https://duckduckgo.com/duckduckgo-help-pages/results/duckassistbot/ on 14 September 2026.
Should you block DuckAssistBot?
The cleanest opt-out decision in this directory, because DuckDuckGo has removed the usual uncertainty: blocking it costs you the AI answers and provably nothing else.
Which cuts both ways. If you are comfortable being quoted with a link, there is no hidden cost to allowing it either, and the traffic is a referral rather than a substitution.
Give it three days before judging the result.
Questions
- Does blocking DuckAssistBot hurt my DuckDuckGo rankings?
- No. DuckDuckGo states that opting out does not impact organic search rankings and does not affect whether your site appears in its search results.
- How long until a block takes effect?
- 72 hours, per DuckDuckGo's own documentation. That is longer than OpenAI's stated 24 hours, so a block that appears not to have worked on day one may simply not have propagated.
The user agent and IP figures on this page were read from DuckDuckGo’s own URLs on 14 September 2026. Blocking figures come from our survey of 170 well-known sites across 10 categories on 14 September 2026, 148 of which returned a readable robots.txt.
Is DuckAssistBot allowed on your site right now?
The checker reads your live robots.txt and reports every token in this directory, with the exact directive that decided each one.