Haystack vs Letta — AI Tool Comparison

TL;DR: Haystack is a mature, production-focused framework for building RAG pipelines and agents with emphasis on modularity, vendor flexibility, and enterprise deployment capabilities. Letta takes a research-driven approach centered on persistent memory and continual learning, enabling agents that evolve their knowledge over time without retraining through novel features like git-based context versioning and offline reasoning. Choose Haystack for robust, deployable AI systems with standard workflows, or Letta for experimental agents where long-term memory persistence and autonomous improvement are critical requirements.

	Haystack The open-source AI framework for production-ready agents, RAG & context engineering Visit	Letta An AI research lab building self-improving agents that remember everything and learn continuously. Visit
Category	Agent frameworks	Agent frameworks
Pricing	Freemium	Freemium
Starting price
Free tier
Audience	Technical	All audiences
API available
Open source
Self-hostable
Model provider	Agnostic (OpenAI, Anthropic, Mistral, Hugging Face, and more)
Founded		2023
Headquarters	Berlin, Germany	San Francisco, USA
Key strengths	·Modular, composable pipeline architecture with full transparency and debuggability ·Vendor-agnostic integrations across LLMs, vector stores, and data sources ·Production-ready with Kubernetes support, serializable pipelines, and cloud-agnostic deployment ·Supports advanced RAG, agentic workflows, multimodal AI, and conversational AI	·Persistent, evolving agent memory and identity ·Continual learning — agents improve over time without retraining ·Git-based memory versioning for reproducible context management ·Sleep-time compute for offline reasoning during idle periods

Haystack

The open-source AI framework for production-ready agents, RAG & context engineering

Visit

Letta

An AI research lab building self-improving agents that remember everything and learn continuously.

Visit