AI Memory Tools Compared: The Complete 2025 Landscape

Quick Decision Guide

The Complete Comparison Matrix

= Full support | = Partial/via plugins | = Not supported

Individual Tool Summaries

Obsidian

Best for: Personal knowledge management with complete data ownership.

Pricing: Free for personal use. Sync $4/mo, Publish $8/mo, Commercial $50/year.

Strengths: Local-first, Markdown files you own, 1000+ plugins, graph visualization, incredible customization.

Limitations: No native AI, setup complexity, not designed for multi-AI access, links not typed relationships.

Notion AI

Best for: Teams needing an all-in-one workspace with AI assistance.

Pricing: Business $20/user/mo (AI included). Plus $12/mo (limited AI).

Strengths: Powerful 3.0 agents (20+ min tasks), extensive integrations, real-time collaboration, polished UX.

Limitations: Data stays in Notion, expensive per-seat, no structured query access, not truly portable.

ChatGPT Memory

Best for: ChatGPT-only users who want zero configuration.

Pricing: Included in ChatGPT (Free tier has basic memory).

Strengths: Zero setup, automatic memory, seamless experience, free tier access.

Limitations: Locked to ChatGPT, ~1,200 word limit, black box storage, can't export, reliability issues.

Claude Memory

Best for: Claude users who appreciate transparent, file-based memory.

Pricing: Pro/Max required (~$20-40/mo).

Strengths: Transparent CLAUDE.md files, project scoping, import/export, incognito mode.

Limitations: Claude-only, paid plans only, no structured queries, still siloed despite transparency.

Mem0

Best for: Developers building AI apps who want popular, well-supported tooling.

Pricing: Free tier (10K memories), usage-based pro plans.

Strengths: 41K GitHub stars, $24M funding, 3-line SDK integration, AWS partnership, active community.

Limitations: Vector similarity (not exact queries), no relational aggregations, cloud-dependent.

Zep (Graphiti)

Best for: Enterprise agents needing temporal reasoning and graph-based memory.

Pricing: Credit-based, startup credits available.

Strengths: State-of-the-art benchmarks (94.8% DMR), bi-temporal model, automatic entity extraction, SOC 2.

Limitations: Graph complexity, higher learning curve, primarily enterprise-focused.

Xtended

Best for: Users who need portable knowledge across all AI tools with relational queries.

Pricing: Free tier, usage-based scaling.

Strengths: Works from Claude, ChatGPT, Cursor, your apps. Relational queries with auto-expand. Explicit relationships. Aggregations and insights.

Limitations: Cloud-based (no local-first), newer product, growing feature set.

Choosing the Right Tool

If portability matters most → Xtended

You use Claude today, ChatGPT tomorrow, Cursor for coding. Your knowledge should work in all of them without reconfiguration.

If local data ownership matters most → Obsidian

Your files, your machine, your control. No cloud dependency if you don't want it.

If team workspaces matter most → Notion

Docs, wikis, projects, collaboration—all in one place with AI assistance.

If zero setup matters most → ChatGPT/Claude Memory

Already using these tools? Their built-in memory just works. Accept the lock-in trade-off.

If developer ecosystem matters most → Mem0

The most popular framework with the biggest community and integrations.

If temporal reasoning matters most → Zep

When you need to know what was true when, and how facts evolved over time.

The Market Reality

The AI memory space is heating up:

• Market size: $20B in 2024 → $62B by 2033 (13.6% CAGR)
• MCP adoption: Now supported by OpenAI, Anthropic, Google; donated to Linux Foundation
• Consolidation: Meta acquired Limitless (Rewind) in December 2025
• Portability gap: Most solutions still lock you into one platform

Our Take

We built Xtended because we saw a gap: there was no way to have one knowledge layer that worked across all AI tools with real relational queryability.

But we're not pretending Xtended is right for everyone:

• If you live in Obsidian and love the local-first philosophy, stay there.
• If your team runs on Notion and AI stays within it, Notion AI is excellent.
• If you only use one AI and don't need portability, built-in memory works.

We built Xtended for people who work across tools and need their knowledge to travel with them—queryable, structured, and always accessible.