florajs

Beautiful, interactive diagrams from Mermaid-compatible syntax — the Python interface to Flora.

• Jupyter-native: diagrams display interactively (zoom, pan, hover highlighting, click links) right in the notebook.
• Headless SVG export: to_svg() runs the Flora renderer in an embedded V8 engine — no browser, no Node.js.
• Two ways in: a programmatic builder, or raw Flora/Mermaid syntax.

pip install florajs

Quick start

from florajs import Flowchart

fc = Flowchart("LR", theme="tufte")
fc.node("raw", "Raw events", shape="cylinder")
fc.node("clean", "Cleaned", shape="stadium")
fc.edge("raw", "clean", "dbt run")
fc  # displays interactively in Jupyter

Or from raw Flora/Mermaid syntax:

from florajs import Diagram

d = Diagram("""
flowchart TD
  a[Start] --> b{Decide}
  b -->|yes| c([Done])
  b -->|no| a
""", theme="sketch")
d.to_svg_file("decision.svg")

Building diagrams

fc = Flowchart("TD")                       # TB | TD | BT | LR | RL

fc.node("a", "Label", shape="diamond")     # rect | rounded | circle | diamond
                                           # stadium | cylinder | queue
fc.edge("a", "b", "maybe",                 # optional edge label
        style="dotted",                    # solid | dotted | thick
        arrow="bidirectional")             # arrow | open | bidirectional

with fc.subgraph("Ingest"):                # groups nest
    fc.node("api", "API")
    fc.node("queue", "Queue", shape="queue")

fc.link("api", "https://example.com/api",  # click-through links
        tooltip="API docs", target="_blank")

Every builder method chains: fc.node("a").edge("a", "b").

Rendering

Themes

Presets: default, tufte, digital, sketch. Or pass a dict of theme overrides:

Diagram(src, theme={"background": "#0b1021", "fontSize": 13})

Errors you can trust

Flora never renders silently wrong output. Lines that cannot be parsed are skipped and reported as a FloraSyntaxWarning; pass strict=True to raise FloraParseError instead:

Diagram(src, strict=True).to_svg()  # raises FloraParseError on any skipped line

Development

The package embeds a JS bundle built from the repository root:

npm run build:python        # builds and vendors flora.iife.js
cd python
pip install -e ".[dev]"
pytest