--- title: Medium | daily.dev description: Dash 2.14 introduced `_allow_dynamic_callbacks=True`, the first official relaxation of Dash's core architectural constraint that all callbacks must be... canonical: https://daily.dev/posts/medium-9d1gqffdw twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Medium | daily.dev og:description: Dash 2.14 introduced `_allow_dynamic_callbacks=True`, the first official relaxation of Dash's core architectural constraint that all callbacks must be... og:url: https://daily.dev/posts/medium-9d1gqffdw og:image: https://api.daily.dev/og/posts/9D1GqFFDW.png og:image:alt: Medium og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # Medium **[Medium](https://daily.dev/sources/medium_js)** · 14 min read · 0 upvotes · 0 comments ## Summary Dash 2.14 introduced `_allow_dynamic_callbacks=True`, the first official relaxation of Dash's core architectural constraint that all callbacks must be registered before app startup. The post explains why the static dependency graph existed, what workarounds developers used before (pattern matching callbacks, pre-registering fixed maximums, offloading to Redis/WebSockets), and how the new feature works mechanically — parent callbacks can now register child callbacks at runtime, with the browser receiving incremental `/_dash-dependencies` updates. Key limitations are covered honestly: no `unregister_callback()` API causes memory growth, multi-user sessions aren't isolated, and multi-worker deployments break the model entirely. A core contributor called it 'dangerous' and 'not for production, multi-user, or multi-process use.' The post also traces Dash's broader trajectory through 3.3 and 3.4, arguing 2.14 was the first crack in the static model, and advises when to use the feature vs. when to avoid it. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Similar posts on daily.dev - [Medium](https://daily.dev/posts/medium-dfrkwlvw4) · Medium · 0 upvotes · 0 comments - [Dynamic Ruby And Hidden Maintenance Costs](https://daily.dev/posts/dynamic-ruby-and-hidden-maintenance-costs-jnxrbecmr) · RUBYLAND · 0 upvotes · 0 comments --- Tags: [#webdev](https://daily.dev/tags/webdev), [#python](https://daily.dev/tags/python), [#reactive-programming](https://daily.dev/tags/reactive-programming), [#plotly](https://daily.dev/tags/plotly) [View this post on daily.dev](https://daily.dev/posts/medium-9d1gqffdw) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"Medium","url":"https://daily.dev/posts/medium-9d1gqffdw","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/medium-9d1gqffdw"},"datePublished":"2026-07-21T08:08:41.345Z","dateModified":"2026-07-21T08:09:51.812Z","description":"Dash 2.14 introduced `_allow_dynamic_callbacks=True`, the first official relaxation of Dash's core architectural constraint that all callbacks must be...","image":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/418de887d952bbce25d95ba27a809ecb?_a=AQAEuop","thumbnailUrl":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/418de887d952bbce25d95ba27a809ecb?_a=AQAEuop","isAccessibleForFree":true,"articleSection":"Medium","inLanguage":"en","publisher":{"@type":"Organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180}},"author":{"@type":"Organization","name":"Medium","logo":"https://media.daily.dev/image/upload/t_logo,f_auto/v1/logos/medium","url":"https://daily.dev/sources/medium_js"},"commentCount":0,"discussionUrl":"https://daily.dev/posts/medium-9d1gqffdw","interactionStatistic":[{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":0},{"@type":"InteractionCounter","interactionType":{"@type":"CommentAction"},"userInteractionCount":0}],"keywords":"webdev,python,reactive-programming,plotly","timeRequired":"PT14M"} {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://daily.dev"},{"@type":"ListItem","position":2,"name":"Medium","item":"https://daily.dev/sources/medium_js"},{"@type":"ListItem","position":3,"name":"Medium"}]} ```