Mailbox MCP vs assistant-ui

A side-by-side comparison built from both listings. Blank cells mean the company has not given that detail; we never guess.

Mailbox MCP compared with assistant-ui
Detail	Mailbox MCP	assistant-ui
What it does	Connect Claude, ChatGPT or any AI to your email mailbox	Open-source React components and runtimes for building AI chat
Stage	Established	Not given
Founded	2002	Not given
Based in	GB	US
Pricing model	Freemium	Open source
Pricing	Free: 5 calls per mailbox per day, no card required. Pro: £34.99 per mailbox per year plus VAT (£2.92 monthly equivalent). Team Access: Team 3 at £119.99 per year plus VAT, Team 5 at £199.99 per year plus VAT, Team 10 at £399.99 per year plus VAT per account.	The core library is free and MIT licensed. assistant-cloud offers: Free ($0, 200 MAU included), Pro ($50/mo, 500 MAU included plus $0.10 per additional MAU), Enterprise (custom MAU pricing, contact for details).
Key features	Read email without marking as read Read attachments: PDFs, spreadsheets, photos Reply in thread with proper headers Send as any of your email aliases Email routines on a schedule Permission levels per connection Works with Gmail, Outlook and IMAP	Streaming support for real-time chat output Tool execution and integration Thread persistence and history Voice support Generative UI rendering Message attachments Conversation branching Multi-platform support (React, Vue, React Native, Ink) Runtime adapter support (AI SDK, LangGraph, LangChain) Fully customizable component composition
What makes it different	Leaves mailbox completely untouched—no duplicate sent items, no marked-as-read flags, threading preserved Works with any MCP-compatible AI—not limited to Claude or ChatGPT Attachments never encoded—up to 20 MB, four ways to attach without passing through AI Email routines run automatically on schedule without manual prompts	Works with any backend through pluggable runtime adapters Complete source code available for customization via CLI Production-ready runtime handling streaming, tools, and state Free MIT license with optional paid cloud persistence Cross-platform support with single chat model
Free plan	Not given	Not given
Open source	Not given	Not given
Platforms	Not given	Not given
Public API	Not given	Not given
Community votes	0	0
DR (Domain Rating by Ahrefs)	26 +1 (up) since last check	53 +1 (up) since last check
Trust Flow (Majestic)	34	12
Citation Flow (Majestic)	32	39
Referring domains (Majestic)	61	572

6 details filled in for both companies.

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