AI tool comparison
Insomnia vs Pretty Fish
Which one should you ship with? Here is the side-by-side panel verdict, pricing read, reviewer split, and community vote comparison.
Developer Tools
Insomnia
The open-source API development platform
67%
Panel ship
—
Community
Free
Entry
Insomnia by Kong is an open-source API client with design, debug, and test capabilities. Supports REST, GraphQL, gRPC, and WebSocket with a clean interface.
Developer Tools
Pretty Fish
Free, beautiful Mermaid diagram editor that works offline
75%
Panel ship
—
Community
Free
Entry
Pretty Fish is a free, open-source Mermaid diagram editor with live preview, 5 built-in themes, multi-page workspaces, and one-click SVG/PNG export. It works offline as a Progressive Web App (PWA) and requires no account, no login, and no installation. It supports all 14+ Mermaid diagram types including flowcharts, sequence diagrams, Gantt charts, entity-relationship diagrams, and Git graphs. The editor includes syntax highlighting, auto-completion, instant error feedback, and a clean split-pane layout. The multi-page workspace lets you manage entire diagram projects in a single session. Export quality is excellent — SVG output is clean and scaling-ready for use in presentations, docs, or design systems. Pretty Fish hit Hacker News front page today with 128 points and has the makings of the go-to Mermaid editor for developers who generate diagrams from AI-assisted documentation workflows. With LLMs increasingly generating Mermaid syntax in their outputs, having a polished renderer and editor matters more than ever.
Reviewer scorecard
“Clean UI, open source, and supports every protocol. The git-based sync is useful for teams.”
“The official Mermaid live editor is clunky and slow. Pretty Fish loads instantly, works offline, and the multi-page workspace means I can manage all my architecture diagrams in one place. Bookmarking this immediately as my default Mermaid editor.”
“Lighter than Postman and open source. For most API development needs, it's the right balance of features.”
“It's a genuinely nice editor but it's solving a niche problem — most devs who need Mermaid diagrams already use VS Code extensions or embed them in Notion. And with no backend, there's no collaboration or sharing story, which limits its use in team workflows.”
“Functional but the UI isn't remarkable. It gets the job done without inspiring joy.”
“Five beautiful themes and clean SVG exports mean I can finally use Mermaid diagrams in client-facing presentations without them looking like developer scratch notes. This is the Mermaid editor I've always wanted and the zero-friction setup seals it.”
“As AI tools increasingly output Mermaid syntax to explain architectures and flows, the need for a great rendering environment grows. Pretty Fish positions itself at the intersection of AI-generated diagrams and human editing — that's a well-timed niche.”
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