Line9
Ranked 11 of 11 diagram tools by recommenders
People recommend Line9 as a free, private Mermaid renderer with a better diagram interface and less time spent fixing layouts. Critics point to the per-seat Pro price and diagram compatibility.
People recommend Line9 as a free, private Mermaid renderer with a better diagram interface and less time spent fixing layouts. Critics point to the per-seat Pro price and diagram compatibility.
11 people gave an opinion
- recommend it
- 9
- criticize it
- 2
- approval share
- 82%
Recommended in 1 of 13 months
- November 2025: not recommended
- December 2025: not recommended
- January 2026: not recommended
- February 2026: not recommended
- March 2026: not recommended
- April 2026: not recommended
- May 2026: not recommended
- June 2026: not recommended
- July 2026: not recommended
- August 2026: recommended
- September 2026: not recommended
- October 2026: not recommended
- November 2026: not recommended (month in progress)
Why it doesn’t carry the badge
- 9 people recommend itNeeds 10 or more, not met.
- 4.5 recommenders for every criticNeeds 2 to 1 or better, met.
- Recommended in 1 of 13 monthsNeeds 4 or more, not met.
The same three rules apply to every product, and the badge can’t be bought. How the badge works
What people say about it
The reasons people give, with the number of comments that give each one. Open a reason to read what they said.
Why people recommend it
Each mark is one comment
Better diagram interface than Mermaid
“line9 solve the ui experience of diagram than vanilla mermaid”
Comment from 12 Aug 2026 in “Show HN: Line9 - a Mermaid rendering engine with its own layout” “This solves my biggest gripe with Mermaid.”
Comment from 12 Aug 2026 in “Show HN: Line9 - a Mermaid rendering engine with its own layout” Less time spent fixing diagrams
“if I consider the amount of time spent correcting diagrams in excalidraw $10 / month seems more than reasonable to me”
Comment from 12 Aug 2026 in “Show HN: Line9 - a Mermaid rendering engine with its own layout” “something like this could be useful to me to improve that intial layout”
Comment from 12 Aug 2026 in “Show HN: Line9 - a Mermaid rendering engine with its own layout”
Other diagram tools people recommend
The four most recommended other diagram tools, with the same counts for each, so you can compare like for like. The tick on each bar marks the 2 to 1 line the badge needs.
| Product | Recommend | Criticize | Approval | Months | Owned | Badge |
|---|---|---|---|---|---|---|
| Mermaid | 93 | 46 | 67% | 12 | — | Approved |
| Reladraw | 28 | 7 | 80% | 1 | — | — |
| SQL to ER diagram tool | 27 | 1 | 96% | 2 | — | — |
| D2 diagram language | 21 | 6 | 78% | 6 | — | Approved |
| Line9This page | 9 | 2 | 82% | 1 | — | — |
What people said
11 of the 14 comments that mention it, newest first. Each links to the original comment.
“completely free, private, needs no signup, and gives you export to SVG and PNG”
“If the company would pay for it I certainly would use it.”
“lets your AI show you the diagram visually as soon as it's created”
“Delighted that you saw improvements.”
“something like this could be useful to me to improve that intial layout”
“line9 solve the ui experience of diagram than vanilla mermaid”
“Publishing a diagram from Line9 Pro gives you a stable URL that serves a pre-rendered SVG”
“if I consider the amount of time spent correcting diagrams in excalidraw $10 / month seems more than reasonable to me”
“It doesn't work with 4 of 5 diagrams from our codebase”
“there's no way my org would pay 120 a year per seat for this”
“This solves my biggest gripe with Mermaid.”
Counts come from 1,795,640 Hacker News comments, November 2025 to November 2026. How we count. Report a mistake.