Starlette Async Jinja

starlette-async-jinja

[](https://github.com/lesleslie/crackerjack) [](https://github.com/lesleslie/oneiric) [](https://github.com/astral-sh/uv) [](https://www.python.org/downloads/)

An asynchronous Jinja2 template integration for Starlette and FastAPI, built on top of the `jinja2-async-environment` package.

Quick Links

• Features
• Template Rendering Pipeline
• Requirements
• Basic Usage
• Testing

Quality & CI

Crackerjack is the standard quality-control and CI/CD gate for this repo. Keep local validation aligned with the same Ruff, typing, security, and test workflow used in CI.

Features

• Fully async template rendering - Load templates and render them asynchronously
• Seamless framework integration - Works with Starlette and FastAPI request/response cycles
• Template fragments - Render specific blocks from templates
• Template partials - Include sub-templates with their own context using render_block
• Fast JSON responses - Enhanced JSON responses using msgspec for faster serialization
• Context processors - Add global context to all templates
• Performance optimizations - Context processor caching, fragment caching, and memory pooling
• Configurable caching - Fine-tune cache sizes and TTL for optimal performance

Installation

pip install starlette-async-jinja

Template Rendering Pipeline

The following diagram shows how a request flows through the async template rendering system:

flowchart TD
    A[HTTP Request] --> B[Starlette/FastAPI Route Handler]
    B