Haystack vs Letta (formerly MemGPT)

Detailed side-by-side comparison to help you choose the right tool

Haystack

🔴Developer

AI Development Platforms

Production-ready Python framework for building RAG pipelines, document search systems, and AI agent applications. Build composable, type-safe NLP solutions with enterprise-grade retrieval and generation capabilities.

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Starting Price

Free

Letta (formerly MemGPT)

🔴Developer

AI Knowledge Tools

Revolutionary AI memory platform that solves the context window problem by giving AI agents persistent, unlimited memory that learns and evolves over time, enabling truly stateful conversations and document analysis beyond traditional LLM limitations.

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Starting Price

Free

Feature Comparison

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FeatureHaystackLetta (formerly MemGPT)
CategoryAI Development PlatformsAI Knowledge Tools
Pricing Plans19 tiers8 tiers
Starting PriceFreeFree
Key Features
  • Workflow Runtime
  • Tool and API Connectivity
  • State and Context Handling
  • Persistent memory across sessions
  • Virtual context management
  • Self-editing memory agents

Haystack - Pros & Cons

Pros

  • Pipeline-of-components architecture enforces type-safe connections, catching integration errors at build time not runtime
  • Deepest RAG-specific feature set: document preprocessing, hybrid retrieval, reranking, and evaluation built into the framework
  • YAML serialization of entire pipelines enables version control, sharing, and deployment of complete configurations
  • 15+ document store integrations with a unified API — swap from Elasticsearch to Pinecone with a single component change
  • Mature evaluation framework for measuring retrieval recall, answer quality, and end-to-end pipeline performance

Cons

  • Component-based architecture has a steeper learning curve than simple chain-based frameworks for basic use cases
  • Haystack 2.x is a full rewrite — v1 migration is non-trivial and much community content still references the old API
  • Agent capabilities are more limited than dedicated agent frameworks like CrewAI or AutoGen
  • Pipeline overhead adds latency for simple single-LLM-call use cases that don't need the full component model

Letta (formerly MemGPT) - Pros & Cons

Pros

  • Solves the fundamental context window limitation of traditional LLMs
  • True persistent memory that enables long-term agent relationships
  • Transparent memory management with user control and visibility
  • Model-agnostic architecture supporting all major LLM providers
  • Both cloud-hosted and self-hosted deployment options
  • Strong API and SDK support for developers
  • Unique memory palace visualization for understanding agent cognition
  • Continuous learning and improvement capabilities

Cons

  • Requires technical knowledge for setup and configuration
  • Memory management complexity can be overwhelming for beginners
  • Self-hosted deployment requires ongoing maintenance
  • Usage costs can accumulate with heavy memory operations
  • Smaller ecosystem compared to established frameworks like LangChain
  • Learning curve for developers used to stateless systems

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🔒 Security & Compliance Comparison

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Security FeatureHaystackLetta (formerly MemGPT)
SOC2
GDPR
HIPAA
SSO
Self-Hosted✅ Yes
On-Prem✅ Yes
RBAC
Audit Log
Open Source✅ Yes
API Key Auth
Encryption at Rest
Encryption in Transit
Data Residency
Data Retentionconfigurable
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