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Sequence diagram
Sketch sequence diagrams by clicking or dragging from the palette: objects / stick actors, solid / dashed / open-arrow messages, self messages, notes, activation bars and stage dividers. Click any element on the canvas to rename it, restyle the line, swap the sender or receiver, move it up or down, with undo and redo. Prefer text? Switch to the script tab, type a few lines like “who -> whom: what” and apply them to the canvas in one go. JSON data can be imported and exported, the script is one click to copy, and the picture can be exported as PNG / SVG / PDF or copied to the clipboard. Four colour themes are available; the canvas follows the system’s light or dark mode while exported images always come on a light sheet. Rendering and export all happen locally in your browser — nothing leaves your machine.
Free and no sign-up. Sequence diagram computes and renders entirely in your browser; nothing you enter is uploaded.
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Frequently asked questions about Sequence diagram
- How is this page different from the Mermaid diagram page?
- Both get you a sequence diagram quickly, but they work differently: the Mermaid page takes full Mermaid code (the kind found in READMEs and AI answers), while this page is a drag-and-drop palette — click or drag in objects, messages, notes and activation bars, then click any element on the canvas to edit it. If you prefer text, switch to the script tab and apply it as a whole. To render sequence-diagram code you already have, use the Mermaid page; to sketch an interaction by hand, drag it together here.
- How do I edit elements already on the canvas?
- Click a participant, message, note, activation bar or divider on the canvas and a properties panel opens in the lower right: rename it, change the shape (object / actor), restyle the line (solid / dashed / open arrowhead), swap the sender or receiver, move it up or down, or delete it. Participants can also be dragged between columns — hold “Hold & drag to a column” in the panel and drop them where you want.
- Which syntax is supported (script mode)?
- participant: name declares a participant (they are also registered automatically in order of first appearance); A -> B: text draws a solid arrow, A --> B a dashed reply, A ->> B / A -->> B open arrowheads and A -> A a self message; note over A: text adds a sticky note, note over A,B spans two columns; activate A / deactivate A draw activation bars; == title == inserts a stage divider; blank lines and // comments are ignored. Up to 12 participants and 120 events; overlong text is truncated automatically.
- What can be exported?
- The page opens with a default sample diagram — drag elements or edit the script to keep going; canvas content is not saved automatically, and a refresh or later visit returns to the sample. To keep your work, use "Export JSON" (re-import it next time to continue editing). Export the picture as PNG (double size) / SVG / PDF, copy it to the clipboard in one click, or save the script as a .txt file. Exports are always light-coloured on white, easy to paste into documents or print; everything happens locally — nothing is uploaded to a server and nothing is written to browser storage.
- Do I need to register or pay to use Sequence diagram?
- Almost every tool is free, needs no registration or sign-in and has no usage limit; the few pay-per-use features (such as AI watermark removal, AI image generation, AI upscaling, AI annotation, and AI flowchart, mind-map and Mermaid generation) state their prices on the page.
- Is the data I process with Sequence diagram uploaded to a server?
- No. Calculation and rendering run locally in the browser and your input is never sent to a server; only the IP address page asks our backend for your outbound address when it opens, and that request carries none of your input. Features that need the backend (such as AI watermark removal, AI image generation, AI upscaling, AI annotation, AI flowchart and mind-map generation and "Financial statements – Small Business Accounting Standards") state their upload scope on their own pages.
About Local Toolbox
Local Toolbox gathers the small tools you reach for every day into one place: formatters, encoding converters, date maths, ID card and address parsing, image and QR code handling, password and amount conversion. Open a page and start working — no sign-up, and almost every tool has no usage limit.
Most features compute inside your browser, so your input never leaves your device; the pages are plain static assets, load fast and keep working offline. The IP page asks our backend for your outbound address when it opens and sends none of your input. AI watermark removal, AI background removal, AI image generation and AI upscaling send content to our backend for inference (watermark removal is ¥1 per run; background removal is ¥1 per run; image generation and upscaling are priced by resolution — 2K ¥2, 4K ¥3); AI annotation sends images to a large model that locates the target and returns coordinates (¥0.5 per image, refunded only when every image in the batch fails); AI flowchart, AI mind-map and AI Mermaid chart generation send your text description to a model that builds the diagram (three separate products, charged ¥0.5, ¥0.5 and ¥0.5 per run respectively); and the accounting helper sends the income, expense, social-insurance and balance figures you fill in to generate a report (¥0.5 for the spoken analysis, ¥1 for the report). These features accept Alipay only, upload nothing before payment succeeds, and refund automatically if processing fails.
- Local first: Parsing, conversion, encoding and image processing all happen in your browser and nothing you type is uploaded (AI watermark removal and AI background removal need the image, AI image generation and upscaling need one upload to obtain a URL, AI annotation needs the images for the model, AI résumé rewriting needs your résumé text, AI flowchart and mind-map generation need your text description, and the accounting helper needs the figures you submit).
- Pay per use, prices in plain sight: Almost every tool is free, needs no account and has no usage limit. Only AI watermark removal (¥1 per run), AI background removal (¥1 per run), AI image generation and AI upscaling (2K ¥2, 4K ¥3), AI annotation (¥0.5 per image), AI résumé rewriting (¥0.5 per run), AI flowchart, mind-map and Mermaid chart generation (¥0.5, ¥0.5 and ¥0.5 per run) and the accounting helper (¥0.5 for the spoken analysis, ¥1 for the report) are charged per use. Payment is Alipay only, nothing is uploaded before you pay, and failed runs are refunded automatically.
- One link per tool: Every tool has its own link, so bookmarks and shared URLs always land on the same page.
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