Mnemosphere is an AI research workspace with multi-model chat, parallel prompts, mindmaps and critique. Paid plans only, from $25/mo. See features and pros.
Researched and fact-checked by Bartu Cavusoglu · Updated October 26, 2026
Mnemosphere is a paid AI research workspace that puts models from several AI labs into one chat interface. Instead of subscribing separately to ChatGPT, Claude and Gemini, users pick from GPT-5.5, Claude 4.6 Sonnet, Gemini 3.1 Pro, Grok 4.2, Perplexity Sonar, OpenAI o3, Claude Opus 4.7 and DeepSeek V4 Pro in one place.
The company says more than 500 researchers, founders, product managers and analysts use it. It is operated by Mnemosphere Pte Ltd and also has an iOS app called Sphere. The positioning is a tool for heavy users who have outgrown a single-model chatbot and want to compare, critique and organize AI answers.
A user types one prompt and chooses up to three models. The answers stream in parallel, side by side. Models can be added, removed or switched during a conversation, and every selected model answers each follow-up. Because each model knows what the others said, a user can ask one model to evaluate another's answer.
Users can attach up to five files per question, including PDF, CSV, Excel, images, code files, YouTube links and webpage URLs. Web search can be switched on before submitting, and it works across every supported model, returning cited answers rather than relying only on training data.
Beyond multi-model chat, Mnemosphere adds parallel prompts, which send several prompt variations at once, and one-click critique, which flags missing context, weak assumptions and counter-arguments in an answer. One-click mindmaps convert text answers into interactive diagrams, and a highlighter lets users mark passages and attach notes they can jump back to.
Long conversations are handled by a conversation index, Lite Threads for side questions, and an Open in New Window option for side-by-side comparison. Chat with YouTube lets users query a video's transcript and comments, and Prompt Assist inserts power phrases into prompts. Image and video generation are listed as not yet available.
Mnemosphere is a paid AI research workspace that gives users access to models from multiple AI labs in one chat interface. It adds tools such as parallel prompts, mindmaps, critique, a highlighter with notes and YouTube chat. It is aimed at researchers, founders, product managers and analysts.
Plans start from $25 per month. There are two tiers, Pro and Ultra, and yearly billing includes two months free. The source text does not show the Ultra price.
No. Mnemosphere states it has paid plans only and no free tier. Both Pro and Ultra come with a 14-day money-back guarantee.
Flagship models include GPT-5.5, Claude 4.6 Sonnet, Gemini 3.1 Pro, Grok 4.2 and Perplexity Sonar. Reasoning models include OpenAI o3, Claude Opus 4.7 with Extended Thinking and DeepSeek V4 Pro. The company says new frontier models are added as they ship.
A user chooses up to three models and asks one question, and all three answer in parallel side by side. Models can be added, removed or swapped mid-conversation, and every selected model responds to follow-ups. Each model also knows what the others said.
No. The company states that prompts, uploads and chats are never used to train any model.
It accepts PDF, CSV, Excel, images, code files such as .py, .html, .json and .js, YouTube URLs and webpage URLs. Users can attach up to 5 files per question.
Pro covers all frontier models, multimodel chat, parallel prompts, mindmaps, highlighter and notes, critique and YouTube chat, with up to 200 messages a month. Ultra adds multi-model deep research, Pro Mindmaps, Lite Threads, up to 1,000 messages a month, personalized support and first access to experimental features.