Langfuse vs Sickle
A side-by-side comparison built from both listings. Blank cells mean the company has not given that detail; we never guess.
Langfuse compared with Sickle
| Detail | L
Langfuse | 
Sickle |
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| What it does | Open Source Agent Evals & Observability
| Email MCP server for Claude, Cursor and other AI agents to access every mailbox you own
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| Stage | Established
| Not given
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| Founded | Not given
| Not given
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| Based in | DE
| GB
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| Pricing model | Freemium
| Free trial
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| Pricing | Not given
| Monthly: €8.99/month after 7-day free trial. Yearly: €30/year (€2.50/month equivalent, 72% savings). Includes both the Mac app and the MCP connector.
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| Key features | - Hierarchical traces capture every LLM call, tool invocation, and retrieval step
- LLM-as-a-judge, heuristic functions, or human review evaluations
- Prompt management with one-click deployments and rollbacks
- Playground to test prompts on real production inputs and compare models
- Experiments with test cases and side-by-side comparison
- Human annotation and collaborative human-in-the-loop workflows
- Cost and latency monitoring with dashboards and alerts
- REST APIs and Query SDK for data access
- Langfuse Assistant to automate the AI engineering loop
| - Search across multiple mailboxes simultaneously
- Read full email threads with conversation history
- Move, archive and mark emails as read
- Scoped permissions: read, change, and send separately
- Attach files up to 18 MB to drafts and emails
- Download and open email attachments
- Native macOS mail client included
- Support for multiple email providers
- Encrypted file handling during transfer
- Revoke access anytime within the hour
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| What makes it different | - MIT licensed open source platform with no data lock-in
- Enterprise scale architecture handling billions of monthly events
- Works with any language and framework with no framework lock-in
- Async by default so tracing never blocks your application
| - Works with any MCP client, not locked to one AI platform
- No installation required; works on macOS, Windows and Linux
- Access unlimited email accounts simultaneously in one connection
- Send emails with opt-in permission and approval workflow
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| Free plan | Not given
| Not given
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| Open source | Not given
| Not given
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| Platforms | Not given
| Not given
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| Public API | Not given
| Not given
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| Community votes | 0 | 0 |
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| DR (Domain Rating by Ahrefs) | 80 ▲ +1 (up) since last check | 13 ▲ +1 (up) since last check |
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| Trust Flow (Majestic) | 35 | 8 |
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| Citation Flow (Majestic) | 54 | 22 |
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| Referring domains (Majestic) | 6114 | 17 |
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5 details filled in for both companies.
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