Is Letta or Windmill better?

Neither clearly leads. Letta starts at Free and Windmill at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.

Which is cheaper, Letta or Windmill?

Letta starts at Free and Windmill at Free.

Does Letta or Windmill run on more platforms?

Letta runs on Web. Windmill runs on web, api, linux, windows, mac.

Can I use Letta for free?

Both have a free tier, so you can try either at no cost before committing.

What is Letta best used for?

Letta is most often used for building agents with memory for continuous learning, enabling reflection during idle periods via sleep-compute, managing agent context and extracting learnings. Of those, building agents with memory for continuous learning and enabling reflection during idle periods via sleep-compute are not what Windmill is typically brought in for.

What can Letta do that Windmill cannot?

Windmill covers Script-to-workflow engine, Auto-generated UIs, Self-hosted deployment, Git sync.

Automation Integration · head to head

Letta vs Windmill

Letta

Automation Integration

Machines that learn

From: Free
Rated: -

Full review Website

Windmill

Automation Integration

Open-source developer platform for building scripts, workflows, and internal apps

From: Free
Rated: -

Full review Website

The short version

Each has a real cost: Letta free tier limited to 3 stateful agents; Windmill free self-hosted tier caps SSO users at 10 and workspaces at 3, requiring Enterprise for larger teams.
Prices and features above were last checked on 29 August 2026.

Where they differ

Only the attributes on which Letta and Windmill actually diverge.

Attributes where Letta and Windmill differ
Attribute	Letta	Windmill
Pricing model	freemium	open-source
Platforms	Web	web, api, linux, windows, mac

Identical on both: starting price (Free), free tier (Yes), user rating (Not yet rated), category (Automation Integration).

What each one covers

Drawn from each product's published feature list. An absence here means we hold no record of it - not that the product lacks it.

Only in Letta

Nothing recorded that Windmill does not also cover.

Only in Windmill

Script-to-workflow engine
Auto-generated UIs
Self-hosted deployment
Git sync
SSO support
Audit logs

What people use each for

The jobs each tool is most often brought in to do.

Letta

Building agents with memory for continuous learningnot Windmill
Enabling reflection during idle periods via sleep-computenot Windmill
Managing agent context and extracting learningsnot Windmill

Windmill

Turning ad-hoc scripts into scheduled jobs and APIsnot Letta
Building internal tools from existing Python/TypeScript codenot Letta
Self-hosted automation for engineering teamsnot Letta
Orchestrating multi-language workflowsnot Letta

Where each one falls short

Documented limitations, not opinions. Every one is a constraint you would hit in normal use.

Letta

Free tier limited to 3 stateful agents
Pro tier capped at 20 stateful agents
API Plan usage charges apply beyond base tier

Windmill

Free self-hosted tier caps SSO users at 10 and workspaces at 3, requiring Enterprise for larger teams.
Compute unit and seat-based pricing (developer vs. operator seats, worker compute units) adds pricing complexity beyond a flat monthly fee.
Email triggers are capped at 100/day on the free tier, limiting event-driven use cases without upgrading.
Smaller ecosystem of pre-built integrations compared to more established automation tools like n8n.

Pricing, plan by plan

Letta

Free

FreeFree
- Limited agents
- Limited Letta Auto usage
- Bring your own API keys
Pro$20/month
- Weekly and monthly Letta Auto quota
- Pay-as-you-go overage
- Up to 20 stateful agents
API Plan$20/month
- Unlimited agents
- $0.10/active agent/month
- $0.00015/second for tool execution
Teams Pro$20/month
- Per seat pricing
- Add teammates
- Letta Auto quota

Windmill

Free

Free / Open-sourceFree
- Unlimited executions
- Self-hosted deployment
- Max 10 users with SSO
Enterprise$120/month
- Unlimited executions and workspaces
- Uncapped SSO seats
- 24/7 priority support (3-hour response)

Which should you pick?

Choose Letta if

You want to start without paying.

Letta review

Choose Windmill if

You need script-to-workflow engine.
You want to start without paying.
You work on web, api, linux, windows, mac.
You also want auto-generated uis.

Windmill review

Questions people ask

Is Letta or Windmill better?: Neither clearly leads. Letta starts at Free and Windmill at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Letta or Windmill?: Letta starts at Free and Windmill at Free.
Does Letta or Windmill run on more platforms?: Letta runs on Web. Windmill runs on web, api, linux, windows, mac.
Can I use Letta for free?: Both have a free tier, so you can try either at no cost before committing.
What is Letta best used for?: Letta is most often used for building agents with memory for continuous learning, enabling reflection during idle periods via sleep-compute, managing agent context and extracting learnings. Of those, building agents with memory for continuous learning and enabling reflection during idle periods via sleep-compute are not what Windmill is typically brought in for.
What can Letta do that Windmill cannot?: Windmill covers Script-to-workflow engine, Auto-generated UIs, Self-hosted deployment, Git sync.

Answered from the vendors’ own pages

Letta: How much does Letta cost?

Letta offers a free tier, then Pro plan at $20/month with up to 20 stateful agents, API Plan at $20/month base plus usage charges ($0.10/active agent/month, $0.00015/second for tool execution), and Teams Pro at $20/seat/month.

Source

Windmill: What does Windmill cost?

Windmill's Free and Open-source edition is $0/month for self-hosted use with unlimited executions, while Enterprise starts at $120/month with unlimited workspaces and uncapped SSO seats, priced further by developer/operator seats and compute units.

Source

Letta: How many agents can I create on the free plan?

The free tier is limited to 3 stateful agents. Pro plan allows up to 20 stateful agents, while API Plan offers unlimited agents.

Source

Windmill: Is there a free plan and what are its limits?

The free self-hosted plan supports unlimited executions but caps SSO at 10 users, workspaces at 3, groups/permissions at 4, and email triggers at 100 per day.

Source

Letta: Does Letta charge for tool execution?

On the API Plan, Letta charges $0.00015 per second for tool execution. The Pro and Teams Pro plans include execution in their monthly fee.

Source

Windmill: How is usage metered on Windmill Enterprise?

Enterprise usage is metered through seats (developer seats at $20/month, operator seats at $10/month) and compute units, e.g. $100/month for 2 standard-worker compute units.

Source

Windmill: What happens to a self-hosted Windmill deployment if the company shuts down?

The pricing page addresses this directly as an FAQ topic, noting that self-hosted applications built on the open-source edition can continue running independently of Windmill the company.

Source

Letta vs Windmill

Letta

Windmill

The short version

Where they differ

What each one covers

Only in Letta

Only in Windmill

What people use each for

Letta

Windmill

Where each one falls short

Letta

Windmill

Pricing, plan by plan

Letta

Windmill

Which should you pick?

Choose Letta if

Choose Windmill if

Questions people ask

Answered from the vendors’ own pages

Related pages

More on Letta

More on Windmill

Keep looking

Other head to heads