Kortex vs Letterhead
Side-by-side comparison of features, pricing, and ratings
At a glance
| Dimension | Kortex | Letterhead |
|---|---|---|
| Pricing | Free (limited) / Paid (upcoming price increase) | Contact sales (custom enterprise pricing) |
| Target User | Solo creatives, note-takers, bloggers | Teams managing multiple newsletters |
| Core Feature | AI assistant kAI for summaries, research, study plans | AI agents for content curation and segmentation |
| Integrations | Readwise | Zapier, MCP server |
| Platform Shift | Transitioning to Eden (2025-11-24 news) | No major platform shift |
| Best For | Minimalist writers, content creators, second brain builders | Media companies, publishers, enterprise newsletter teams |
Choose Kortex if you're a solo creator who wants an AI-powered second brain for writing and knowledge management. Choose Letterhead if you're a team scaling multi-newsletter operations with advanced automation and analytics. They serve fundamentally different needs, so pick based on your primary workflow.
Kortex is an AI writing workspace and second brain for minimalist writers and note-takers — now rebranding to Eden.
Visit Website
Letterhead is a multi-newsletter email operating system for portfolio production, intelligence, and revenue at scale.
Visit WebsiteWhat real users say: Kortex vs Letterhead
Not marketing copy and not our opinion — a structured sweep of public discussion (reviews, forums, communities and video comments), showing what people praise and what they complain about for each tool.
Kortex
41 mentions across 2 sources · 3% positive — critical (averaged across 2 sources)
Hacker News, App Store
What users praise
- • AI assistant (kAI) can summarize, research, and create study plans from various sources.
- • Interconnected writing surfaces related ideas from notes and highlights in real time.
- • Kortex Elements offer templates and outlines to guide writing projects.
- • Advanced search by tags, related words, and contents across captures and highlights.
What frustrates them
- • Mobile app is buggy, crashes often, and lacks basic scrolling and navigation.
- • Does not save reading position when switching apps on mobile.
- • No chapter selection on mobile; must exit book fully or type page numbers.
- • Freezes every few minutes on MacBook Air requiring restart.
Researched Jul 3, 2026
Letterhead
No verifiable community signal. We scanned public discussion on Jul 16, 2026 and found posts matching the name “Letterhead”, but could not establish that they are about this product rather than something else sharing its name. Rather than publish a score built on the wrong subject, we publish none.
Who should pick which
- Solo bloggerPick: Kortex
Kortex offers AI assistance for writing and note-taking, a focus mode, and a free tier – ideal for individual content creators on a budget.
- Newsletter team (3+ newsletters)Pick: Letterhead
Letterhead provides portfolio management, AI agents for curation, approval flows, and unified analytics – built for teams scaling multi-newsletter operations.
- Knowledge worker building a second brainPick: Kortex
Kortex's interconnected writing and kAI for research/summaries align perfectly with building a personal knowledge base.
- Media company with ad revenue from newslettersPick: Letterhead
Letterhead includes direct ads, programmatic, and revenue management – essential for monetizing newsletters at scale.
Frequently Asked Questions
Kortex vs Letterhead: which should you choose?
Choose Kortex if you're a solo creator who wants an AI-powered second brain for writing and knowledge management. Choose Letterhead if you're a team scaling multi-newsletter operations with advanced automation and analytics. They serve fundamentally different needs, so pick based on your primary workflow.
Is Kortex free?
Kortex has a free plan with limitations (15 AI requests/month, no offline mode, limited file uploads). Paid plans are coming with a price increase announced in Jan 2025.
Does Letterhead have a free trial?
No. Letterhead requires contacting sales for pricing – no self-serve trial is available.
Can I use Kortex for email marketing?
No. Kortex is for note-taking and writing, not email campaigns. Letterhead is purpose-built for newsletters.
Which tool supports team collaboration?
Letterhead offers approval flows, workspaces, and governance for teams. Kortex has document sharing but collaboration features are not mature.
What integrations are available?
Kortex integrates with Readwise; Letterhead integrates with Zapier and has a native MCP server for AI agent integrations.
Is Kortex migrating to a new platform?
Yes. As of Nov 2025, Kortex is transitioning to Eden – users can transfer their workspace.
What AI models does Kortex use?
Kortex uses multiple models: base AI, Gemini 2.0/2.5 Flash, Llama 4 Scout, via its kAI assistant.
Can Letterhead replace my ESP?
Yes, Letterhead Suite acts as a full ESP with sending infrastructure, audience management, and deliverability tools.
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Last reviewed: July 3, 2026