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Python Fragments

Modern HTML template rendering in Python - no build step, no template files, and native HTML awareness out of the box.

# main.py
from fragments import loader

from views import render_index

# views.py
from my_components import Layout, PostCard

POSTS = [...]  # your data here

def render_index() -> str:
    published = [p for p in POSTS if p.published]
    return <>
        <Layout title="My Blog">
            <h1>Latest Posts</h1>
            <PostCard for={{ post in published }} post={{ post }} />
        </Layout>
    </>

# main.py
from fragments import loader

from fastapi import FastAPI
from .index import router

app = FastAPI()
app.include_router(router)

# index.py
from fastapi import APIRouter
from fastapi.responses import HTMLResponse

router = APIRouter()

POSTS = [...]  # your data here

@router.get("/", response_class=HTMLResponse)
async def index() -> str:
    published = [p for p in POSTS if p.published]
    return <>
        <Layout title="My Blog">
            <h1>Latest Posts</h1>
            <PostCard for={{ post in published }} post={{ post }} />
        </Layout>
    </>

# app.py
from fragments import loader

from flask import Flask
from views import index_bp

app = Flask(__name__)
app.register_blueprint(index_bp)

# views.py
from flask import Blueprint

index_bp = Blueprint("index", __name__)

POSTS = [...]  # your data here

@index_bp.route("/")
def index() -> str:
    published = [p for p in POSTS if p.published]
    return <>
        <Layout title="My Blog">
            <h1>Latest Posts</h1>
            <PostCard for={{ post in published }} post={{ post }} />
        </Layout>
    </>

# urls.py
from fragments import loader

from django.urls import path
from views import index

urlpatterns = [path("", index)]

# views.py
from django.http import HttpRequest, HttpResponse

POSTS = [...]  # your data here

def index(request: HttpRequest) -> HttpResponse:
    published = [p for p in POSTS if p.published]
    return HttpResponse(<>
        <Layout title="My Blog">
            <h1>Latest Posts</h1>
            <PostCard for={{ post in published }} post={{ post }} />
        </Layout>
    </>)

Why Fragments?

  • No build step

    Transpiled automatically at import time. No CLI, no watchers, no separate compile phase.

  • Full IDE Support

    Type checking, hover, completions, go-to-definition, rename, and semantic highlighting via a built-in language server and VS Code extension.

  • Production Tested

    Used in production and developed in-house by TheRunningAlgorithm, exposed to thousands of live users prior to open source release

  • Long Term Support

    Actively maintained by TheRunningAlgorithm, who use it in production.

Get Started

1. Install

pip install python-fragments

Register the loader at your app's entry point, before importing any modules that use fragments:

from fragments import loader
from my_components import my_component

Any .py file containing <> is transpiled automatically — nothing else to configure.

Full installation guide

2. Use With Your IDE

Install the language server for inline type errors, completions, and hover docs:

pip install python-fragments[lsp]

A VS Code extension is included with structural syntax highlighting, semantic tokens, diagnostics, go-to-definition, rename, and more.

Full IDE setup guide