--- title: Protobuf-ES is the only fully-compliant Protobuf library... description: Protobuf-ES, Buf's JavaScript/TypeScript Protobuf implementation, passes 100% of required and 99.8% of recommended conformance tests from the official Protobuf... canonical: https://daily.dev/posts/protobuf-es-is-the-only-fully-compliant-protobuf-library-for-javascript-buf-abdlpyjbl twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Protobuf-ES is the only fully-compliant Protobuf library for JavaScript · Buf | daily.dev og:description: Protobuf-ES, Buf's JavaScript/TypeScript Protobuf implementation, passes 100% of required and 99.8% of recommended conformance tests from the official Protobuf... og:url: https://daily.dev/posts/protobuf-es-is-the-only-fully-compliant-protobuf-library-for-javascript-buf-abdlpyjbl og:image: https://api.daily.dev/og/posts/aBDlpyJbl.png og:image:alt: Protobuf-ES is the only fully-compliant Protobuf library for JavaScript · Buf 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. # Protobuf-ES is the only fully-compliant Protobuf library for JavaScript · Buf **[Buf Blog](https://daily.dev/sources/buf)** · 7 min read · 0 upvotes · 0 comments ## Summary Protobuf-ES, Buf's JavaScript/TypeScript Protobuf implementation, passes 100% of required and 99.8% of recommended conformance tests from the official Protobuf spec, making it 99.95% conformant overall and the most conformant JS Protobuf library, surpassing even Google's own google-protobuf library. By contrast, the widely used Protobuf.js library is only around 31% conformant despite over 12 million weekly NPM downloads. The conformance test suite, containing over 2,000 tests, validates serialization/deserialization correctness across binary and JSON formats. A real example is given: a bug in Protobuf-ES's Duration type JSON serialization caused negative durations to lose their sign, which the conformance suite caught in CI before it could cause cross-service data corruption. Buf released a new Protobuf Conformance repository to let developers compare implementations and help other libraries improve their conformance. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Questions this post answers ### How conformant is Protobuf-ES compared to other JavaScript Protobuf libraries? Protobuf-ES passes 100% of required and 99.8% of recommended conformance tests from the official Protobuf spec, for a total of 99.95% conformance, failing only one test related to unsupported proto2 extensions. By comparison, Protobuf.js, despite having over 12 million weekly NPM downloads, is only around 31% conformant, and Protobuf-ES even exceeds Google's own google-protobuf JavaScript library. _daily.dev surfaces conformance and reliability comparisons for developers picking a serialization library._ ### How should a Protobuf Duration of 0 seconds and -100000000 nanos be serialized to JSON? It should serialize to the string "-0.1s", preserving the negative sign, per the Duration Well-Known Type's JSON mapping rules where seconds are suffixed with "s" and negative durations must retain their sign. A bug in Protobuf-ES once dropped this sign, producing "0.1s" instead, which could cause two services to disagree on the actual duration value. _Developers debugging cross-service serialization mismatches can track library conformance issues on daily.dev._ ## Similar posts on daily.dev - [Protobuf-ES just got a lot faster · Buf](https://daily.dev/posts/protobuf-es-just-got-a-lot-faster-buf-rcovndatq) · Buf Blog · 18 upvotes · 1 comments - [Google Protocol Buffers flaw turns schemas into shells](https://daily.dev/posts/google-protocol-buffers-flaw-turns-schemas-into-shells-ssmnskxpa) · CSO Online · 8 upvotes · 0 comments - [Critical flaw in Protobuf library enables JavaScript code execution](https://daily.dev/posts/critical-flaw-in-protobuf-library-enables-javascript-code-execution-1jn7mj8hc) · BleepingComputer · 7 upvotes · 1 comments - [Better than JSON](https://daily.dev/posts/better-than-json-d2je9kyed) · Hacker News · 250 upvotes · 22 comments - [TypeScript 6.0 is your final warning](https://daily.dev/posts/typescript-6-0-is-your-final-warning-2tbdrcemi) · Bytes by ui.dev · 144 upvotes · 15 comments --- Tags: [#javascript](https://daily.dev/tags/javascript), [#testing](https://daily.dev/tags/testing), [#backend](https://daily.dev/tags/backend), [#typescript](https://daily.dev/tags/typescript) [View this post on daily.dev](https://daily.dev/posts/protobuf-es-is-the-only-fully-compliant-protobuf-library-for-javascript-buf-abdlpyjbl) ```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":"Protobuf-ES is the only fully-compliant Protobuf library for JavaScript · Buf","url":"https://daily.dev/posts/protobuf-es-is-the-only-fully-compliant-protobuf-library-for-javascript-buf-abdlpyjbl","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/protobuf-es-is-the-only-fully-compliant-protobuf-library-for-javascript-buf-abdlpyjbl"},"datePublished":"2026-08-23T07:20:09.507Z","dateModified":"2026-08-23T07:20:31.694Z","description":"Protobuf-ES, Buf's JavaScript/TypeScript Protobuf implementation, passes 100% of required and 99.8% of recommended conformance tests from the official Protobuf...","image":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/2622f358a00bf92e479b721a5e1256ec?_a=AQAEuop","thumbnailUrl":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/2622f358a00bf92e479b721a5e1256ec?_a=AQAEuop","isAccessibleForFree":true,"articleSection":"Buf Blog","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":"Buf Blog","logo":"https://media.daily.dev/image/upload/s--2YBgo_Nm--/f_auto,q_auto/v1787469605/logos/buf?_a=BAMAMicg0","url":"https://daily.dev/sources/buf"},"commentCount":0,"discussionUrl":"https://daily.dev/posts/protobuf-es-is-the-only-fully-compliant-protobuf-library-for-javascript-buf-abdlpyjbl","interactionStatistic":[{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":0},{"@type":"InteractionCounter","interactionType":{"@type":"CommentAction"},"userInteractionCount":0}],"keywords":"javascript,testing,backend,typescript","timeRequired":"PT7M"} {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://daily.dev"},{"@type":"ListItem","position":2,"name":"Buf Blog","item":"https://daily.dev/sources/buf"},{"@type":"ListItem","position":3,"name":"Protobuf-ES is the only fully-compliant Protobuf library for JavaScript · Buf"}]} {"@context":"https://schema.org","@type":"FAQPage","@id":"https://daily.dev/posts/protobuf-es-is-the-only-fully-compliant-protobuf-library-for-javascript-buf-abdlpyjbl#faq","mainEntity":[{"@type":"Question","name":"How conformant is Protobuf-ES compared to other JavaScript Protobuf libraries?","acceptedAnswer":{"@type":"Answer","text":"Protobuf-ES passes 100% of required and 99.8% of recommended conformance tests from the official Protobuf spec, for a total of 99.95% conformance, failing only one test related to unsupported proto2 extensions. 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