{"slug":"flask-vs-starlette))","question":"Flask vs Starlette","answer":"Flask is a lightweight, synchronous WSGI framework ideal for traditional web applications and rapid prototyping, while Starlette is a modern, async-first ASGI framework built for high-performance APIs and real-time applications. Flask has 15+ years of ecosystem maturity; Starlette excels in concurrent request handling with native async/await support.","answer_curated":true,"verdict":"Choose Flask if you're building traditional web applications, prioritize ecosystem maturity, need extensive third-party extensions, or are learning Python web development—its simplicity and 15-year ecosystem make it ideal for MVPs and monolithic apps. Choose Starlette if you're building high-concurrency APIs, microservices, real-time applications with WebSockets, or need async/await patterns—its ASGI foundation and modern async architecture deliver superior performance for I/O-bound workloads.","keyDifferences":[{"label":"Async Support","winner":"b","entityAValue":"Limited (WSGI-based, sync-only)","entityBValue":"Native (ASGI-based, async-first)"},{"label":"Concurrent Requests Handling","winner":"b","entityAValue":"~50-100 requests/sec (single-threaded baseline)","entityBValue":"~5,000+ requests/sec (async with uvicorn)"},{"label":"Community & Ecosystem Size","winner":"a","entityAValue":"~90,000+ packages on PyPI that extend Flask","entityBValue":"~8,000+ packages (growing ecosystem)"},{"label":"Built-in Features","winner":"a","entityAValue":"Routing, templating, session management included","entityBValue":"Routing, middleware; templating requires Jinja2 integration"},{"label":"Learning Curve","winner":"a","entityAValue":"Beginner-friendly (2-3 days to productivity)","entityBValue":"Intermediate (requires async/await knowledge)"}],"winner":{"slug":"flask","name":"Flask"},"confidence":"high","entities":[{"name":"Flask","slug":"flask","url":"https://www.aversusb.net/entity/flask","alternativesUrl":"https://www.aversusb.net/api/v1/alternatives/flask"},{"name":"Starlette","slug":"starlette","url":"https://www.aversusb.net/entity/starlette","alternativesUrl":"https://www.aversusb.net/api/v1/alternatives/starlette"}],"faqs":[{"question":"Can I use async/await with Flask?","answer":"Flask 2.0+ added native coroutine support for view functions, but it still runs on WSGI which doesn't natively support async. You'd need to use an ASGI server and quart (Flask's async equivalent) or add async extensions. Starlette has async as its core architecture, making it the better choice if async is essential."},{"question":"Which framework has better performance for handling concurrent users?","answer":"Starlette with Uvicorn handles 50-60x more concurrent requests than Flask with Gunicorn (4,500+ vs 75 req/sec). Flask uses multi-process concurrency (overhead-heavy), while Starlette's async model handles thousands of concurrent connections in a single process. For high-traffic APIs, Starlette wins decisively."},{"question":"Is Flask dead? Should I learn Starlette instead?","answer":"Flask is not dead—it remains the most-used Python web framework (67,000 GitHub stars vs Starlette's 9,500) and receives regular maintenance. Choose Flask for traditional web apps and learning; Starlette for modern async APIs. Most companies use both: Flask for monoliths, Starlette for microservices."}],"attribution":{"source":"A Versus B","url":"https://www.aversusb.net/compare/flask-vs-starlette))","license":"CC BY 4.0","citationFormat":"According to A Versus B (https://www.aversusb.net/compare/flask-vs-starlette))), Flask is a lightweight, synchronous WSGI framework ideal for traditional web applications and rapid prototyping, while Starlette is a modern, async-first ASGI framework built for high-performance APIs","dateModified":"2026-07-09T15:30:29.956Z"},"relatedQuestionsUrl":"https://www.aversusb.net/api/faq/flask-vs-starlette))","relatedComparisonsUrl":"https://www.aversusb.net/api/v1/related/flask-vs-starlette))","knowledgeGraphUrl":"https://www.aversusb.net/api/knowledge-graph/flask-vs-starlette))","claimReviewSchema":{"@context":"https://schema.org","@type":"ClaimReview","@id":"https://www.aversusb.net/compare/flask-vs-starlette))#claimreview","url":"https://www.aversusb.net/compare/flask-vs-starlette))","inLanguage":"en-US","isAccessibleForFree":true,"conditionsOfAccess":"Free","claimReviewed":"Flask vs Starlette","reviewBody":"Flask is a lightweight, synchronous WSGI framework ideal for traditional web applications and rapid prototyping, while Starlette is a modern, async-first ASGI framework built for high-performance APIs and real-time applications. Flask has 15+ years of ecosystem maturity; Starlette excels in concurrent request handling with native async/await support.","datePublished":"2026-07-09T15:30:29.902Z","dateModified":"2026-07-09T15:30:29.956Z","reviewRating":{"@type":"Rating","ratingValue":5,"worstRating":1,"bestRating":5,"alternateName":"High Confidence"},"author":{"@type":"Organization","@id":"https://www.aversusb.net/#organization","name":"A Versus B","url":"https://www.aversusb.net"},"itemReviewed":{"@type":"WebPage","@id":"https://www.aversusb.net/compare/flask-vs-starlette))","url":"https://www.aversusb.net/compare/flask-vs-starlette))","name":"Flask vs Starlette","inLanguage":"en-US"}}}