Optimizing for ChatGPT, Perplexity, Gemini, and Copilot: what differs and what doesn't

People now ask AI assistants the questions they used to type into a search box. Each assistant has its own way of finding and citing sources, which raises a fair question: do you need a separate strategy for each one?

Mostly, no. The foundations are shared. But a few differences are worth knowing, especially around which search index each assistant leans on.

What they have in common

All the major assistants that cite sources follow a similar pattern when they browse:

1. Turn the user's prompt into one or more search queries. 2. Retrieve results from a web index. 3. Read the top pages and extract relevant passages. 4. Write an answer and cite the pages they used.

So the shared requirements are the same ones covered in our GEO guide:

• Be crawlable and indexed.
• Rank for the questions people ask.
• Provide clear, quotable answer units.
• Look trustworthy, with clear authorship and an identifiable organization.

Where they differ

Different underlying indexes

This is the most practical difference. Assistants rely on different search infrastructure, and the details change over time:

• Microsoft Copilot is built on Bing.
• Gemini and Google's AI Overviews / AI Mode use Google Search.
• ChatGPT search and Perplexity use a combination of their own crawlers and third-party search providers.

The takeaway: do not neglect Bing. Many sites only verify in Google Search Console. Setting up Bing Webmaster Tools, submitting your sitemap there, and using IndexNow makes your new content discoverable faster for any assistant that uses Bing results.

Different crawlers

Each company runs its own bots, for example OAI-SearchBot and GPTBot (OpenAI), PerplexityBot, Google-Extended (a control token for Gemini training), and Bingbot. Check your robots.txt and CDN or firewall rules. It is common to find AI crawlers blocked by accident, which quietly removes you from those answers.

Decide deliberately. Some organizations allow search-focused bots (which drive citations and referral traffic) while restricting training-only bots.

Different citation styles

• Perplexity shows citations prominently and tends to cite more sources per answer, so it often sends noticeable referral traffic.
• AI Overviews show a small set of linked sources alongside the summary.
• ChatGPT cites inline or in a sources panel when it browses, but answers from its built-in knowledge without browsing do not cite live pages at all.
• Copilot shows numbered footnote-style citations from Bing results.

Training data vs. live retrieval

When an assistant answers without browsing, it relies on what it learned in training. You cannot directly optimize for that in the short term, but a consistent brand presence across the web, including your site, reviews, directories, documentation, and third-party mentions, makes it more likely your brand is described accurately.

A cross-assistant checklist

• [ ] Verified in both Google Search Console and Bing Webmaster Tools
• [ ] Sitemap submitted to both; IndexNow enabled for fast Bing discovery
• [ ] robots.txt and firewall reviewed for AI crawler access
• [ ] Organization schema and llms.txt in place
• [ ] Key pages have direct answers near the top
• [ ] Brand facts (what you do, pricing, founding, leadership) are consistent everywhere they appear
• [ ] A fixed prompt set tracked across each assistant

Measure each assistant separately

Visibility can differ a lot between assistants. You might be cited often in Perplexity and rarely in AI Overviews, or the reverse. Track the same prompts across each platform and compare your AI Share of Voice per assistant. The gaps often point straight to the fix: an indexing issue on Bing, a blocked crawler, or a missing answer on a key page.

SearchVoro runs your prompt set across major AI assistants on a schedule, records who gets cited, and shows where your visibility differs by platform, so you know exactly where to focus.