Can Mermaid Chart be vibe coded?
Hosted Mermaid diagrams with visual editing and collaboration
Mermaid Chart's solo core is compact: build a browser-based diagram-as-code editor with drag, resize, connect, keyboard shortcuts, autosave, and SVG or PNG export. A competent builder can reach a useful personal version, while the paid product mainly wins on interaction polish, collaboration.
Jump to the build brief ↓Checked Jul 2026
medium editorial confidence
Buildability by layer
Screens, forms, and focused interactions
The repeatable job the product performs
Availability and legality of required data
Uptime, queues, support, and maintenance
Security, compliance, and user confidence
The achievable core
- Build a browser-based diagram-as-code editor with drag, resize, connect, keyboard shortcuts, autosave, and SVG or PNG export.
- Build a focused single-user workflow with real persistence, search, and export.
- A responsive interface with real empty, loading, success, and error states.
The parts a prompt cannot buy
- high-fidelity import and export
- presentation and enterprise controls
- multiplayer cursors and comments
- large template libraries
- The last 20 percent is sync, migration fidelity, speed, and edge cases.
- Permissions, presence, and shared workflows are difficult to simplify.
Why people still pay
Mermaid Chart: The shapes are easy; customers pay for low-friction editing, reliable exports, collaboration, and a canvas that never fights them.
The last 20 percent is sync, migration fidelity, speed, and edge cases.
Permissions, presence, and shared workflows are difficult to simplify.
The brief
Context, requirements, acceptance criteria, non-goals, and the full production standard — as Markdown, ready for any coding agent.
Build brief — a focused alternative to Mermaid Chart
Context
**Mermaid Chart** — Hosted Mermaid diagrams with visual editing and collaboration. It currently costs Variable pricing.
Mermaid Chart's solo core is compact: build a browser-based diagram-as-code editor with drag, resize, connect, keyboard shortcuts, autosave, and SVG or PNG export. A competent builder can reach a useful personal version, while the paid product mainly wins on interaction polish, collaboration.
This brief describes a focused, single-operator replacement for the part of Mermaid Chart that is genuinely reproducible. It is deliberately narrower than the product it replaces, and it says so in writing. Build the useful core; do not pretend to have rebuilt the rest.
What you are building
Build a browser-based diagram-as-code editor with drag, resize, connect, keyboard shortcuts, autosave, and SVG or PNG export.
Build a focused single-user workflow with real persistence, search, and export.
A responsive interface with real empty, loading, success, and error states.
Requirements
Functional
Node.js 22.
Modern browser.
No account required.
Non-functional
Accessibility: semantic markup, labelled controls, visible focus, and reduced-motion support.
Security: server-side secrets, validated input, and no credentials in the client bundle.
Reliability: retries with backoff on external calls, and a clear failure state when a provider is down.
Portability: the operator can export their data and leave without losing it.
Implementation brief
Build a usable personal replacement for the core loop of Mermaid Chart.
Use exactly this stack: React + TypeScript + Vite + IndexedDB.
Primary job: Build a browser-based diagram-as-code editor with drag, resize, connect, keyboard shortcuts, autosave, and SVG or PNG export.
Start from an empty folder and create the complete working project.
Make the default mode single-user and private.
Store user data locally unless the core job requires the declared self-hosted database.
Do not add analytics, telemetry, ads, or third-party accounts.
Put every secret and external credential in .env and provide .env.example.
Use realistic sample data that is clearly labelled and easy to delete.
Implement the smallest polished interface that completes the core loop end to end.
Include clear empty, loading, validation, success, and failure states.
Add import and export so the user is not trapped in the app.
Use accessible keyboard navigation, labels, focus states, and sensible contrast.
Validate untrusted input and never log secrets or private file contents.
Deliberately exclude these paid-product advantages: high-fidelity import and export; presentation and enterprise controls; multiplayer cursors and comments.
Do not fake integrations, network effects, proprietary data, model quality, compliance, or security claims.
Where an external API is optional, keep the app useful without it and explain the degraded mode.
Write focused unit tests for the data model and the most important workflow.
Add one end-to-end smoke test that proves the core loop works.
Create a README with setup, permissions, architecture, data location, backup, and limitations.
Add scripts for install, development, test, build, and a production-style local run.
Run the tests and build before finishing, then fix errors rather than merely describing them.
Delivery standard
Inspect the repository first, then write a short implementation plan before writing code.
Deliver the smallest complete end-to-end workflow first; every primary control must work against persisted data.
Use real validation and storage; never substitute fake dashboards, decorative controls, hard-coded success states, or mock integrations.
Include responsive layouts plus genuine empty, loading, success, validation, and failure states.
Keep secrets server-side in environment variables, provide .env.example, and never commit credentials or user data.
Add structured logs around every external call and return actionable errors without leaking sensitive details.
Write unit tests for the core logic and one automated test of the main user journey.
Finish with a README covering setup, architecture, data location, backups, tests, deployment, and known limitations.
Acceptance criteria
A clean install starts the app using only the README and .env.example.
The primary journey works from first visit through saved result, reload, edit, export, and deletion where applicable.
Invalid input, missing configuration, provider failure, and an empty database each have a usable state.
The interface works at 390px and 1440px, is keyboard navigable, and shows visible focus on every control.
Tests, type checking, linting, and a production build all pass with no ignored failures.
No part of the interface implies a live integration, security guarantee, or scale capability that was not actually built and verified.
Non-goals
Do not build these, and do not claim to have replaced them:
High-fidelity import and export.
Presentation and enterprise controls.
Multiplayer cursors and comments.
Large template libraries.
The last 20 percent is sync, migration fidelity, speed, and edge cases.
Permissions, presence, and shared workflows are difficult to simplify.
What you still own after launch
Run migrations, backups, restores, and dependency updates.
Test the critical journey after every model, API, or hosting change.
Monitor failures and fix the edge cases a first prompt will miss.
Risk
**Manageable.** A personal version is realistic if you test the critical journey and keep reliable backups.
Editorial confidence in this assessment: medium. No independent one-shot implementation is linked yet.
Prior art
Working open-source software you can read, fork, or borrow from before starting:
[Mermaid](https://github.com/mermaid-js/mermaid) — Text-to-diagram renderer with broad diagram syntax
Generated by [Can It Be Vibe Coded?](https://www.canitbevibecoded.com) · Full report: https://www.canitbevibecoded.com/mermaid-chart
You still own the product
- Run migrations, backups, restores, and dependency updates.
- Test the critical journey after every model, API, or hosting change.
- Monitor failures and fix the edge cases a first prompt will miss.
Open-source prior art
Before you start
Can Mermaid Chart be vibe coded?
Yes, for personal use. Mermaid Chart's solo core is compact: build a browser-based diagram-as-code editor with drag, resize, connect, keyboard shortcuts, autosave, and SVG or PNG export. A competent builder can reach a useful personal version, while the paid product mainly wins on interaction polish, collaboration.
What can an AI coding agent reproduce from Mermaid Chart?
Build a browser-based diagram-as-code editor with drag, resize, connect, keyboard shortcuts, autosave, and SVG or PNG export. Build a focused single-user workflow with real persistence, search, and export. A responsive interface with real empty, loading, success, and error states.
What will a DIY Mermaid Chart replacement still be missing?
high-fidelity import and export; presentation and enterprise controls; multiplayer cursors and comments; large template libraries; The last 20 percent is sync, migration fidelity, speed, and edge cases.; Permissions, presence, and shared workflows are difficult to simplify.
What do I still own after building a Mermaid Chart alternative?
Run migrations, backups, restores, and dependency updates. Test the critical journey after every model, API, or hosting change. Monitor failures and fix the edge cases a first prompt will miss.