n8n vs Windmill: what their users struggle with

Not a verdict and not a star rating: the problems users of n8n and Windmill describe in public, side by side, each one linked to its source (as of 2026-10-15).

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Every count in this table is of open reports in the recent window (n8n since 2023-10, Windmill since 2023-10); older and fixed reports are not counted. The counts measure how much public discussion exists for each product, not which is better: a popular tool collects more reports.

Problems mostly raised about n8n

• MCP tool calls fail with new toolCallId and old workflows stop running after update · Reliability & bugs · Blocks work
• AI Agent node breaks on a simple OpenAI call after upgrading · Reliability & bugs · Blocks work
• MCP Client Tool errors with any Gemini model but works with GPT-4o · Integrations · Annoyance
• Editor websocket fails behind nginx reverse proxy after upgrade · Self-hosting & upgrades · Blocks work
• MCP client cannot connect to an n8n MCP server over SSE · Integrations · Blocks work

Problems mostly raised about Windmill

• Python Azure script installs the wrong package and then fails · Reliability & bugs · Blocks work
• Sync resource types with Hub fails with an authentication error · Integrations · Blocks work
• Windmill containers crash on Raspberry Pi 5 with jemalloc page-size error · Self-hosting & upgrades · Blocks work
• AGPL commercial-license wording makes API-only use look like it triggers copyleft · Pricing & plans · Annoyance
• Initial setup screen fails and admin password cannot be changed on CE · Setup & onboarding · Blocks work

Go further

Open n8n and Windmill in the compare tool to filter by area and severity, n8n alternatives, Windmill alternatives, or the state of workflow automation.

How the data is built. A theme is a group of reports about the same problem; unique means not matched to a theme on the other product.