The best diagram tools, according to hackers
11 diagram tools recommended in Hacker News comments over the past year, ranked by how many separate people recommend each one.
- Most recommendedMermaid93 people recommend it
- Least regretSQL to ER diagram tool27 recommend, 1 criticize
All diagram tools
- MermaidA free text-based diagram tool whose diagrams can be versioned in git and render in GitHub, Markdown and editors, though large diagrams often look messy.93recommend
- ReladrawPeople recommend it as diagram-as-code where you specify relative positions instead of exact coordinates. Critics mention bugs and an LLM-generated README.28recommend
- SQL to ER diagram toolBrowser-based tool that turns a pasted SQL schema into an interactive ER diagram, with nothing uploaded or stored. Some dispute whether SQL can yield a true ER diagram.27recommend
- D2 diagram languageDiagram language people find cleaner and more expressive than Mermaid, with strong icon support. Common caveat: the default layout engine and limited layout control frustrate some users.21recommend
- PlantUMLPlain-text diagrams with strong control and tooling; the usual caveat is harder setup and no native GitHub rendering.16recommend
- GraphvizFree graph layout software that people trust for automatic diagram layout; the most common caveat is that the layout engine decides where things go.13recommend
- Beautiful MermaidRecommended for rendering Mermaid diagrams as ASCII or Unicode text for terminals, AI workflows and DOM-free environments, though critics say the ASCII/Unicode mode doesn't work well.12recommend
- FanfaLets people make consistent, animated Mermaid diagrams that stand out. Critics mostly report sluggishness on Firefox.12recommend
- Pele Mermaid diagram rendererA free Mermaid-syntax renderer that outputs themeable SVG diagrams with a nicer layout and easier embedding on other sites. Critics report that its layout gains are small and that the playground preview and dark-mode examples have problems.12recommend
- TALARecommended as a free auto-layout engine that often produces cleaner diagrams than Mermaid and ELK, and works with D2. Known limitation: weaker than Dagre or ELK on DAG layouts.11recommend
- Line9People 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.9recommend