--- title: How to Avoid Hermes V1's Memory Regression in RN Apps description: Hermes V1 quietly attaches 512KB of debug metadata to every worklet function evaluated at runtime, causing significant memory bloat in React Native apps using... canonical: https://daily.dev/posts/how-to-avoid-hermes-v1-s-memory-regression-in-rn-apps-rtvg21jnz twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: How to Avoid Hermes V1's Memory Regression in RN Apps | daily.dev og:description: Hermes V1 quietly attaches 512KB of debug metadata to every worklet function evaluated at runtime, causing significant memory bloat in React Native apps using... og:url: https://daily.dev/posts/how-to-avoid-hermes-v1-s-memory-regression-in-rn-apps-rtvg21jnz og:image: https://api.daily.dev/og/posts/rTVg21jnZ.png og:image:alt: How to Avoid Hermes V1's Memory Regression in RN Apps 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. # How to Avoid Hermes V1's Memory Regression in RN Apps **[Software Mansion](https://daily.dev/sources/swmansion)** · 6 min read · 0 upvotes · 0 comments ## Summary Hermes V1 quietly attaches 512KB of debug metadata to every worklet function evaluated at runtime, causing significant memory bloat in React Native apps using Reanimated. With 100+ worklets initialized at startup, apps can see 50MB+ extra memory usage. Four fixes are available: (1) enable Worklets Bundle Mode, which avoids eval entirely by exposing the full JS bundle via mmap; (2) use the experimental Hermes Bytecode option for Legacy Eval Mode; (3) pin Hermes to version 0.15 which includes the backported fix; or (4) wait for React Native 0.87, shipping August 8th, which bundles the fixed Hermes. Bundle Mode is the recommended long-term solution as it also brings performance improvements. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Similar posts on daily.dev - [Hermes V1 by Default · React Native](https://daily.dev/posts/hermes-v1-by-default-react-native-obv7ttair) · React Native · 49 upvotes · 0 comments - [The Memory Hermes Can't See: Stale Shadow Nodes in RN](https://daily.dev/posts/the-memory-hermes-can-t-see-stale-shadow-nodes-in-rn-mgjv6pri7) · Software Mansion · 0 upvotes · 0 comments - [How to keep your OTA updates lean and fast](https://daily.dev/posts/how-to-keep-your-ota-updates-lean-and-fast-5kfgiyuhb) · Expo Blog · 0 upvotes · 0 comments - [React Native New Architecture and OTA Updates: What Teams Need to Know in 2026](https://daily.dev/posts/react-native-new-architecture-and-ota-updates-what-teams-need-to-know-in-2026-nzauznyut) · codemagic · 0 upvotes · 1 comments --- Tags: [#react-native](https://daily.dev/tags/react-native) [View this post on daily.dev](https://daily.dev/posts/how-to-avoid-hermes-v1-s-memory-regression-in-rn-apps-rtvg21jnz) ```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":"How to Avoid Hermes V1's Memory Regression in RN Apps","url":"https://daily.dev/posts/how-to-avoid-hermes-v1-s-memory-regression-in-rn-apps-rtvg21jnz","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/how-to-avoid-hermes-v1-s-memory-regression-in-rn-apps-rtvg21jnz"},"datePublished":"2026-08-02T07:15:37.360Z","dateModified":"2026-08-02T07:39:09.438Z","description":"Hermes V1 quietly attaches 512KB of debug metadata to every worklet function evaluated at runtime, causing significant memory bloat in React Native apps using...","image":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/99cdfff901d8ab2bf20b1d3e28f2034b?_a=AQAEuop","thumbnailUrl":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/99cdfff901d8ab2bf20b1d3e28f2034b?_a=AQAEuop","isAccessibleForFree":true,"articleSection":"Software Mansion","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":"Software Mansion","logo":"https://media.daily.dev/image/upload/s--sOx0vaVZ--/f_auto,q_auto/v1785654908/logos/swmansion?_a=BAMAMicg0","url":"https://daily.dev/sources/swmansion"},"commentCount":0,"discussionUrl":"https://daily.dev/posts/how-to-avoid-hermes-v1-s-memory-regression-in-rn-apps-rtvg21jnz","interactionStatistic":[{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":0},{"@type":"InteractionCounter","interactionType":{"@type":"CommentAction"},"userInteractionCount":0}],"keywords":"react-native","timeRequired":"PT6M"} {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://daily.dev"},{"@type":"ListItem","position":2,"name":"Software Mansion","item":"https://daily.dev/sources/swmansion"},{"@type":"ListItem","position":3,"name":"How to Avoid Hermes V1's Memory Regression in RN Apps"}]} ```