# Fullstory vs PostHog: which do AI models recommend for session replay, October 2026

GTM AI Recommendation Index, October 2026 Edition, Session replay and heatmaps. Two of fourteen models named Fullstory first on the direct prompt; two named PostHog. Page: https://gtm-ai-index.com/gtm-data/session-replay-and-heatmaps/fullstory-vs-posthog/

| | First-choice share | Rank | Negative rate | Labels | Models naming it |
|---|---|---|---|---|---|
| Fullstory | 9% | #3 of 10 | 42% | 53 | 14 of 14 |
| PostHog | 7% | #4 of 10 | 5% | 37 | 14 of 14 |

## The direct prompt, model by model

- Perplexity Sonar: fullstory first (first choices: Fullstory) (alternatives: Hotjar, LogRocket)
- Muse Glimmer 30B: fullstory first (first choices: Fullstory) (alternatives: Contentsquare, Heap, Hotjar, Microsoft Clarity, PostHog, VWO)
- DeepSeek V4 Flash: posthog first (first choices: PostHog) (alternatives: Hotjar, LogRocket, Microsoft Clarity, Mouseflow)
- GPT-6 Luna: posthog first (first choices: PostHog) (alternatives: Fullstory, Hotjar)
- Gemini 3.5 Flash: neither first, one named (first choices: Pendo) (alternatives: LogRocket, Mouseflow, PostHog)
- Mistral Small: neither first, one named (first choices: Hotjar, Lucky Orange) (alternatives: Fullstory, PostHog, UXCam)
- Llama 4 Maverick: neither first, one named (first choices: Smartlook) (alternatives: Adobe Analytics, Fullstory)
- GLM 4.7 FlashX: neither first, one named (first choices: Hotjar) (alternatives: Crazy Egg, Fullstory, Microsoft Clarity, Mouseflow)
- MiniMax M2.5: neither first, one named (first choices: Mixpanel) (alternatives: Fullstory, PostHog, UXCam)
- Claude Haiku 4.5: neither named (first choices: Mouseflow) (alternatives: Hotjar)
- GPT-5.4 mini: neither named (first choices: Contentsquare, Mouseflow) (alternatives: LogRocket)
- Grok 4.1 Fast: neither named (first choices: Hotjar) (alternatives: LogRocket, Microsoft Clarity, Mouseflow)
- Qwen 3.7 Flash: neither named (first choices: Hotjar) (alternatives: LogRocket, Matomo)
- Kimi K2: neither named (first choices: Hotjar) (alternatives: LogRocket, Mouseflow, Smartlook)

## What the models said about Fullstory

- "Captures enormous amounts of data; privacy and compliance concerns under GDPR/CCPA; may collect more data than teams can realistically act on" (Kimi K2, negative prompt, hard negative)
- "Skip FullStory/Quantum Metric: While excellent, these tools are generally priced for large enterprises" (Qwen 3.7 Flash, direct prompt, hard negative)
- "If you need high-fidelity replay + search/queryable session intelligence and SOC2-grade compliance: FullStory." (Muse Glimmer 30B, direct prompt, first choice)
- "FullStory and PostHog mask all text by default ... the "mask by default" approach is significantly safer" (Claude Haiku 4.5, negative prompt, first choice)
- "Go with FullStory or Contentsquare for deep session replay and journey analytics." (GLM 4.7 FlashX, comparative prompt, first choice)

## What the models said about PostHog

- "PostHog does offer data scrubbing features, but I was recently surprised to see their announcement about integrating AI to analyze session replays on behalf of users. This raises a red flag" (Muse Glimmer 30B, negative prompt, soft negative)
- "If you enable network capture, scrutinize it separately from replay masking: requests and responses can contain sensitive headers or bodies" (GPT-6 Luna, negative prompt, soft negative)
- "I'd generally recommend PostHog if you want the best balance of visitor behavior analytics, product analytics, and session replay in one place" (GPT-5.4 mini, paraphrase prompt, first choice)

Share is the count of first choices across the direct, paraphrase, budget and scale prompts over all fourteen models, for a mid-market B2B company; rank is within the category. Comparisons are drawn for the top eight products in each category. Published under CC BY 4.0; the output is the models' output, and nothing here is a recommendation by the index.