Diffbot-User
Diffbot uses this crawler to fetch pages in real time when a user asks about them. Fetches pages a Diffbot user explicitly requested.
Crawler data last reviewed September 18, 2026 · all 61 crawlers
Diffbot-User at a glance
| Operator | Diffbot |
|---|---|
| Type | AI assistant fetcher |
| Respects robots.txt | Yes — a Disallow rule is honored |
| If you allow it | Allowing it means users who ask about you get an accurate, current answer with your page as the source. |
| If you block it | Blocking it only affects user-requested fetches, so the traffic cost is small — but the users you do lose are the highest-intent ones. |
What is Diffbot-User?
Fetches pages a Diffbot user explicitly requested. Assistant crawlers fetch a page in real time when a user explicitly asks an AI assistant about it. They do not build a standing index of the web. Blocking them makes the assistant say it cannot access your page instead of summarizing it — a poor experience for users who were actively looking for you.
Allowing it means users who ask about you get an accurate, current answer with your page as the source.
Does Diffbot-User respect robots.txt?
Yes. Diffbot-User honors robots.txt directives, including wildcard rules and Allow lines. A Disallow rule for this crawler is respected — but remember robots.txt is a voluntary protocol across the whole industry, not a wall.
How to block Diffbot-User
Add this group to your robots.txt to deny Diffbot-User across your whole site:
User-agent: Diffbot-User Disallow: /
Blocking it only affects user-requested fetches, so the traffic cost is small — but the users you do lose are the highest-intent ones.
How to allow Diffbot-User
Diffbot-User is allowed by default on every site. It only gets blocked if a matching rule exists — most often a global User-agent: * group with Disallow: /. To exempt it while blocking other bots, put an empty Disallow group for it before the global block:
User-agent: Diffbot-User Disallow: User-agent: * Disallow: /
Does blocking Diffbot-User hurt your rankings?
No — not for classic search. Diffbot-User is not a Google user agent, so a robots.txt rule for it has no effect on Google rankings or indexing. The only thing you give up is what this specific AI assistant fetcher does with your pages, described above.
How to verify Diffbot-User is really hitting your site
robots.txt states what a compliant crawler may fetch; your access log shows what actually happened. Search the log for the token:
grep -i "Diffbot-User" /var/log/nginx/access.log | tail -50
On Cloudflare the free plan does not expose raw request logs, so use Security Events to see blocked requests, or add a console.log line in a Worker to record the user agent. On Vercel or Netlify, filter the request log by user agent string.
User agents are trivially spoofable, which is why "I saw Diffbot-User in my logs" is not proof. Because Diffbot-User is documented to honor robots.txt, a request from it that ignores your rules is worth investigating — but a single stray hit is usually a misconfigured tool, not the real crawler.
Should you block Diffbot-User?
- Allow it — it only fetches pages a user explicitly asked about, so the traffic is high-intent and the volume is low.
- Block it only if a page must never be summarized by an assistant, and accept that the user will be told the page is unavailable.
- Check it after CDN changes — assistant fetchers are frequently caught by bot-fighting rules aimed at scrapers.
Is Diffbot-User currently allowed on your site?
Paste your robots.txt into the free auditor and see verdicts for all 61 AI crawlers — including the specific paths that matter.
Other AI crawlers from Diffbot
Diffbot runs 2 distinct user agents. They are configured independently in robots.txt, so blocking one does not block the others — a detail that catches people out when they assume a single rule covers a whole vendor.
| Crawler | Type | robots.txt | What it does |
|---|---|---|---|
| Diffbot | AI training | yes | Knowledge-graph extraction crawler. |
| Diffbot-User this page | AI assistant fetcher | yes | Fetches pages a Diffbot user explicitly requested. |
Related AI crawlers
Further reading
- How to Get Cited by ChatGPT, Perplexity and Copilot — ChatGPT, Perplexity and Copilot cite pages through a fetch-retrieve-extract pipeline. What each stage rewards, how the engines differ, and a 10-point checklist.
- Content Structure for AI: Pages That Get Extracted and Cited — AI answer engines extract pages in chunks, not wholes. Structure rules that make content quotable: question headings, answer-first paragraphs, tables, FAQs.