LangChain vs Letta (formerly MemGPT)

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

LangChain

AI Development Platforms

The industry-standard framework for building production-ready LLM applications with comprehensive tool integration, agent orchestration, and enterprise observability through LangSmith.

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Starting Price

Free

Letta (formerly MemGPT)

🔴Developer

AI Knowledge Tools

AI memory platform for building stateful agents that can preserve selected context across sessions, manage long conversations, and support applications that need durable agent memory.

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Starting Price

Free ($0/month)

Feature Comparison

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FeatureLangChainLetta (formerly MemGPT)
CategoryAI Development PlatformsAI Knowledge Tools
Pricing Plans8 tiers8 tiers
Starting PriceFreeFree ($0/month)
Key Features
  • LangChain Expression Language (LCEL)
  • 700+ Document Loaders & Integrations
  • Vector Store & Retriever Abstractions
  • Persistent memory across sessions
  • Virtual context management
  • Self-editing memory agents

💡 Our Take

Choose Letta if persistent, inspectable memory across sessions is the core requirement for your agent product. Choose LangChain if your team needs a broader orchestration framework, more general workflow composition, or a larger ecosystem of integrations.

LangChain - Pros & Cons

Pros

  • Largest integration ecosystem in the LLM space — 600+ providers for models, vector stores, tools, document loaders, and embeddings, letting teams swap components without rewriting application code
  • LangSmith observability is best-in-class for LLM apps: full trace timelines, prompt-level cost and latency breakdowns, dataset capture from production, and regression evaluations against custom or LLM-as-judge metrics
  • LangGraph provides explicit, debuggable agent state machines with checkpointing, human-in-the-loop interrupts, and durable execution — significantly more controllable than purely autonomous agent frameworks
  • Strong production tooling: LangGraph Platform handles deployment, persistence, scheduled tasks, and horizontal scaling of agents as APIs without requiring custom infrastructure
  • First-class support for Model Context Protocol (MCP), structured outputs, streaming, and async execution makes it suitable for both real-time chat UIs and long-running background agents
  • Enterprise-grade options including SOC 2 Type II, SSO/RBAC, and self-hosted LangSmith and LangGraph deployments for regulated industries and air-gapped environments

Cons

  • Steep learning curve and frequent API churn — Python and JS packages have been reorganized multiple times (langchain, langchain-core, langchain-community, partner packages), and tutorials online often reference deprecated patterns
  • Heavy abstractions can hide what is actually happening in prompts and tool calls, making debugging harder for newcomers compared to writing direct SDK calls
  • The framework footprint is large; pulling in langchain and its dependencies can add significant cold-start time and package size, which is painful for serverless deployments
  • LangSmith and LangGraph Platform pricing scales with traces and node executions and can become expensive at high volume, pushing teams to self-host or sample traces
  • Documentation, while extensive, is fragmented across LangChain, LangGraph, and LangSmith docs and changes quickly — finding the canonical current pattern for a task often requires reading source code or recent blog posts

Letta (formerly MemGPT) - Pros & Cons

Pros

  • Purpose-built for persistent agent memory, making it a stronger fit than stateless chat tools for assistants that need to remember users, preferences, and prior work across sessions.
  • Supports both cloud-hosted and self-hosted deployment according to the existing directory record, giving technical teams a path for managed usage or more direct infrastructure control.
  • Model-agnostic positioning allows teams to design around an agent memory layer instead of tying all context and behavior to a single LLM provider.
  • Its virtual context approach addresses a concrete limitation of LLM applications: important information can outlive the immediate context window instead of being lost between sessions.
  • The existing listing identifies 5 core feature areas, including persistent memory, virtual context, self-editing agents, document analysis beyond context limits, and multi-session conversation tracking.
  • Compared to broader agent frameworks in our directory, Letta has a clearer focus on long-running, stateful agents rather than general workflow orchestration.

Cons

  • The provided scraped website content did not expose complete current customer counts, founding year, or integration counts, so buyers should verify commercial details before procurement.
  • Persistent memory adds design and governance complexity because teams must decide what agents should store, retrieve, update, or forget over time.
  • Usage-based charges on the API Plan, including $0.10 per active agent per month and $0.00015 per second for server-side tool execution, can make costs harder to forecast for high-volume applications.
  • Self-hosted deployment can require engineering resources for installation, model provider configuration, monitoring, upgrades, and data management.
  • Letta is more specialized than broad frameworks like LangChain or Semantic Kernel, so teams that mainly need general tool orchestration may find its memory-first focus narrower.

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🔒 Security & Compliance Comparison

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