Agentic Index
Letta vs Zep (2026)
Choose Zep for a temporal knowledge graph memory service behind your existing agents, and choose Letta for a stateful agent platform where memory persistence is built into the runtime.
Zep offers a free tier with 1,000 credits a month and Flex from 125 dollars a month, while Letta offers a free tier, Pro at 20 dollars a month, a usage based API, and open source self hosting. Zep's graph tracks how facts change over time, which suits assistants grounded in evolving user data; Letta suits teams betting on stateful agents as the architecture, with the caveat that its recent momentum concentrates in Letta Code.
Choose Letta if
- You want the whole agent lifecycle, including memory, in one open source runtime
- Editing and inspecting agent memory directly is part of your workflow
- A 20 dollars a month entry point for hands on use fits early experimentation
Choose Zep if
- Facts about your users change over time and your memory layer must model that
- You want a managed memory service with a knowledge graph, not a new runtime
- Keeping your current framework while upgrading recall is the goal
| At a glance | Letta | Zep |
|---|---|---|
| Category | Agent infrastructure | Agent infrastructure |
| Entry price | Free tier · Pro $20/mo · usage based API · open source self host | Free (1,000 credits/mo) · Flex $125/mo ($104 annual) · Flex Plus $375/mo · Enterprise custom |
| Free / trial | Free account, no card (up to 3 agents with managed state; BYOK unlimited locally) | Free tier: 1,000 credits/month (1 credit = 1 Episode up to 350 bytes) for development and low volume production. Open source Graphiti engine is free to self host. |
| Pricing confidence | public exact | public exact |
| Feature | L Letta |
Z Zep |
|---|---|---|
| Action & orchestration | ||
|
Integrations & Tool Calling Ability to connect agents to real systems through native integrations, OAuth-authenticated actions, custom tools, APIs, webhooks, or MCP-compatible tools. |
Full / Explicit | Partial |
|
Workflow Orchestration Ability to sequence, branch, retry, route, and combine deterministic workflow nodes with autonomous agent steps. |
Full / Explicit | No / Not documented |
|
Triggers & Channel Coverage How agents wake up and where they work: schedules, webhooks, message events, CRM events, inbox events, chat, email, voice, and collaboration tools. |
Partial | No / Not documented |
| Knowledge & context | ||
|
Knowledge Grounding & RAG Ability to ground agent behavior in company data through document ingestion, retrieval, external knowledge APIs, semantic search, or RAG layers. |
Full / Explicit | Partial |
|
Memory & State Persistence Ability to persist context across a run, conversation, workflow, user, team, or longer-term memory layer. |
Full / Explicit | Full / Explicit |
| Control & trust | ||
|
Human Oversight & Guardrails Approval steps, consent checkpoints, escalation rules, structured guardrails, policy constraints, and pause/resume controls. |
Partial | No / Not documented |
|
Security, Identity & Governance RBAC, SSO, auditability, encryption, least-privilege tool access, compliance posture, and data handling policy. |
Partial | Partial |
|
Observability & Auditability Traces, logs, execution histories, metrics, audit events, and debugging detail for production agent behavior. |
Partial | Partial |
|
Deployment & Data Residency Deployment modes and options, including SaaS, dedicated cloud, VPC, on-prem, hybrid, local runtime, and self-hosting. |
Full / Explicit | Full / Explicit |
| Solution readiness | ||
|
Prebuilt Agents, Templates & Packs Ready-made workflows, packaged employees, templates, blueprints, industry solutions, and role-specific agents that reduce time-to-value. |
Partial | No / Not documented |
| Platform extensibility | ||
|
Model Flexibility & Routing Ability to work across multiple foundation models, route tasks to different models, or let buyers bring their own providers and keys. |
Full / Explicit | Partial |
|
APIs, SDKs & MCP Extensibility Composability layer: stable APIs, SDKs, MCP tool consumption/serving, custom tools, and integration into internal systems. |
Full / Explicit | Full / Explicit |
|
Testing, Debugging & Optimization Testing, debugging, scoring, retries, fallbacks, quality gates, and optimization loops for improving agent workflows before and after deployment. |
Partial | No / Not documented |
| Specialist automation | ||
|
Browser & Computer Use Browser, desktop, or remote/local computer control for workflows that cannot be handled through stable APIs alone. |
No / Not documented | No / Not documented |
Pricing snapshot
Sourced from the Index pricing dataset · open each vendor's profile for full detail.
| Pricing | L Letta |
Z Zep |
|---|---|---|
|
Entry price Lowest public entry point |
Free tier · Pro $20/mo · usage based API · open source self host | Free (1,000 credits/mo) · Flex $125/mo ($104 annual) · Flex Plus $375/mo · Enterprise custom |
|
Pricing confidence How public the numbers are |
Public, exact | Public, exact |
|
Billing Primary billing axis |
usage | Subscription tiers plus credits consumed by data ingestion (1 credit per Episode up to 350 bytes, +1 per additional 350 bytes); retrieval, storage, threads, users, and graph storage consume zero credits |
|
Variable cost Workload / overage exposure |
High variable cost | Low variable cost |
|
Free tier / trial Try before you buy |
Free tier
|
Free tier
|
|
Buying motion Self-serve vs sales call |
Mixed | Self-serve |
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