DiagramLetter
A SaaS that converts Mermaid, PlantUML, or hand-drawn diagrams into beautiful ASCII/UTF-8 art that renders perfectly in any email client, RSS reader, or plain-text CMS.
Tech newsletter writers, developer-relations teams, and email-first publishers who need diagrams that survive any inbox
- Mermaid and PlantUML paste-in conversion with multiple ASCII style presets
- Email-safe output that survives Gmail, Outlook, and Apple Mail quirks
- Visual preview emulating the most common email clients
- Bulk conversion queue for weekly newsletter pipelines
Newsletter writers routinely lose their carefully drawn diagrams to email clients that mangle unicode or strip images — the trending ascdraw proves keyboard-first ASCII art has a real audience, and no one is packaging that aesthetic for publishers yet.
HN show of ascdraw reached only 24 points/4 comments and AsciiSketch 53 points; ASCII diagram editors like ASCIIFlow, Textik, and asciilogic already serve this niche as free tools with no obvious unmet demand for a paid conversion SaaS.ascdraw: Editor for ASCII/UTF-8 diagrams (in 144FPS) | Hacker News ↗ASCIIFlow ↗
The space is crowded with free, established ASCII editors (ASCIIFlow, Textik, asciilogic, asciidiagrams.com, AsciiSketch) — several explicitly market 'email/README embedding', leaving little whitespace for a paid Mermaid→ASCII converter.Textik - ASCII diagrams editor ↗asciilogic — Free Online ASCII Diagram Tool ↗
Newsletter and devrel teams pay for tools (beehiiv $99+/mo, Kit, Substack) but ASCII diagrams are a marginal sub-feature and every direct competitor (ASCIIFlow, Textik, asciilogic) is free, making a standalone paid SaaS hard to monetize.Best Newsletter Platforms in 2026: The Complete Guide for Writers and Creators ↗ASCIIFlow ↗
ASCII art is a decades-old medium and email clients will keep mangling images/unicode, so the underlying need is durable; however, ASCII aesthetic trends come and go and the technical problem can be solved with one-time tooling.
Mermaid/PlantUML → ASCII rendering is non-trivial (requires layout algorithms, box-drawing character selection) but well-scoped — a small team could ship a converter in a few months, and SVG-to-text libraries exist.ascdraw: Editor for ASCII/UTF-8 diagrams (in 144FPS) | Hacker News ↗