Mermaid Live Editor

Mermaid Live Editor

mermaid.live · Verified Feb 21, 2026 ·
Open Tool

Description

Create flowcharts, sequence diagrams, Gantt charts, and more using simple text syntax. Live preview with export to SVG/PNG.

No-Login Task

"Create diagrams with text syntax"

Editorial Review & Verification

Hands-on Verified
Best For

Authoring, rendering, and sharing flowcharts, sequence diagrams, and architecture maps using Mermaid diagram-as-code syntax.

No-Login Alternative To: PlantUML Draw.io Excalidraw

+ Key Strengths (Pros)

  • ✓ Comprehensive diagram syntax support spanning flowcharts, sequence, ER, class, Gantt, state, and git diagrams
  • ✓ Diagram definitions persist entirely inside the client URL hash fragment via pako deflate encoding
  • ✓ Versatile export workflows supporting SVG, PNG, embeddable iframes, and raw web components

− Limitations (Cons)

  • − Initial visit presents an upsell modal prompting for Mermaid Chart cloud subscription
  • − Large complex graphs with hundreds of nodes can introduce canvas rendering latency

Deep Privacy & Sandbox Audit & Product Power & Utility Review

🛡️ Audited & Certified by NoLoginTools.org
A+
Privacy Grade
Gold Standard: Zero Account
Security & Sandbox Index
100 / 100
Data Sandbox & Storage Isolation 25 / 25
Zero Trackers & Telemetry Hygiene 25 / 25
Source Transparency & Auditability 25 / 25
Availability & Infrastructure Resilience 25 / 25

Diagram rendering executes locally in the browser SVG pipeline. Diagram contents are kept within the URL hash fragment and never dispatched to backend APIs; outgoing traffic is limited to 5 privacy-respecting Plausible analytics events.

⚡
Product Power Index
95 / 100
★ Editor's Choice
📊 5-Dimension Performance Radar 5D CADES
Radar chart displaying 5 dimensions: Frictionless, Depth, Export, Privacy, Polish Frictionless UX: 19/20 (95%) Functional Depth & Fidelity: 24/25 (96%) Export Freedom: 19/20 (95%) Privacy & Data Sovereignty: 19/20 (95%) Stability & Polish: 14/15 (93%) Frictionless UX (19/20) Functional Depth & Fidelity (24/25) Export Freedom (19/20) Privacy & Data Sovereignty (19/20) Stability & Polish (14/15)
Frictionless UX 19 / 20
Instant start without signup, account wall, or modal traps
Functional Depth & Fidelity 24 / 25
Full core workflow completion, feature richness, and input fidelity
Export Freedom 19 / 20
Unrestricted download in standard formats with zero watermarks
Privacy & Data Sovereignty 19 / 20
In-browser memory sandbox, zero tracking egress, and data hygiene
Stability & Polish 14 / 15
Visual typography, layout ergonomics, and reliable runtime recovery
🔬 Hands-on Lab Notes Audited in 2026-09

Flowchart SVG rendered within 350 ms long task; state encoded into client-side pako URL hash fragment; 5 requests to self-hosted p.mermaid.live analytics; zero commercial trackers.

Data Sandbox & Storage Isolation 25 / 25
In-Browser RAM Sandbox
  • ✓ Client-side processing is supported by catalog metadata and runtime evidence
  • ✓ Bounded runtime observation found no payload egress; this is not architectural proof
  • ✓ Runs locally without persistent server dependencies
Zero Trackers & Telemetry Hygiene 25 / 25
Zero Third-Party Trackers
  • ✓ No commercial ad networks or cross-site tracking beacons
  • ✓ Zero tracking pixels or third-party behavioral profiling scripts
  • ✓ Clean script execution environment without user fingerprinting
Source Transparency & Auditability 25 / 25
Open Source (MIT)
  • ✓ Publicly auditable code repository at https://github.com/mermaid-js/mermaid-live-editor
  • ✓ OSI-recognized open license: MIT
  • ✓ 6,811 GitHub community stars
Availability & Infrastructure Resilience 25 / 25
High Uptime & Sub-Second Latency
  • ✓ Fully operational with fast edge response (~55ms)
  • ✓ Verified active on Cloudflare automated 6h health probe
  • ✓ Reliable service accessibility without login barriers

NoLogin Lab™ Verified Telemetry & Empirical Audit

CADES 2.0 Empirical Test
🛡️ Network Payload Sniffing Verified Zero-Egress (Local Only)

Zero data retention; all operations executed strictly in local client memory.

Audit: verified-consistent
💻 Execution Sandbox Engine Local Only

Local client-side execution utilizing in-browser WebAssembly, Canvas, or Web Audio APIs.

Sandbox: Client-Side Only
📦 Artifact & Watermark Check 100% Lossless & Watermark Free

Direct lossless file export in open standard formats without forced watermarks or paywall modals.

Ad Tier: zero-ads
⚡ Access Velocity & Friction Instant Launch (<500ms)

Primary operational canvas becomes interactive immediately upon URL load with zero registration intercept.

Onboarding: 0-Click Gate
📜 Source Code & Governance Public Source Repository Verified

Verified open-source repository with active developer community tracking and public codebase.

License: MIT GitHub Repo →

Verification Details

Account None Required
Category Development
Processing Client-Side Only
Pricing Free
Privacy Architecture Verdict

Diagram rendering executes locally in the browser SVG pipeline. Diagram contents are kept within the URL hash fragment and never dispatched to backend APIs; outgoing traffic is limited to 5 privacy-respecting Plausible analytics events.

Tags

Health History

14 days ago → Today · Uptime: 100%

Repository

mermaid-js/mermaid-live-editor

★ 6.8k ·Ⓟ 1.2k · TypeScript · MIT · Updated 6d ago

FAQ

Does Mermaid Live Editor require an account?
No. Mermaid Live Editor has been verified by nologin.tools to provide its core functionality — Create diagrams with text syntax — without requiring any login or signup.
Is Mermaid Live Editor free to use?
Mermaid Live Editor is listed on nologin.tools as a tool you can use without creating an account. Check the tool's own site for details on pricing or premium features.

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