--- title: Delta Kernel - Building Delta Lake connectors, made simple description: Delta Kernel is a set of libraries (Java and Rust, the latter with C/C++ bindings) designed to simplify building connectors for Delta Lake tables by... canonical: https://daily.dev/posts/delta-kernel---building-delta-lake-connectors-made-simple-7wypt0yda twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Delta Kernel - Building Delta Lake connectors, made simple | daily.dev og:description: Delta Kernel is a set of libraries (Java and Rust, the latter with C/C++ bindings) designed to simplify building connectors for Delta Lake tables by... og:url: https://daily.dev/posts/delta-kernel---building-delta-lake-connectors-made-simple-7wypt0yda og:image: https://api.daily.dev/og/posts/7WyPt0Yda.png og:image:alt: Delta Kernel - Building Delta Lake connectors, made simple 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. # Delta Kernel - Building Delta Lake connectors, made simple **[Delta Lake Blog](https://daily.dev/sources/delta-lake)** · 13 min read · 0 upvotes · 0 comments ## Summary Delta Kernel is a set of libraries (Java and Rust, the latter with C/C++ bindings) designed to simplify building connectors for Delta Lake tables by abstracting away complex protocol details like deletion vectors, column mapping, and partition columns. Connector developers only need to work with stable high-level APIs instead of tracking every protocol change, and can upgrade to newer Kernel versions to gain support for new Delta features automatically. Read APIs stabilized starting with Delta 3.0, while write APIs (introduced in Delta 3.2) are still evolving. Early adopters include DuckDB, Apache Druid, Apache Flink (which saw a 45x startup time improvement from partial migration), Delta Sharing, and Delta-rs. The post also covers the architectural challenges of building such a kernel: abstracting table formats versus file formats, supporting distributed engines with the right metadata abstraction, offering pluggable Engine interfaces for resource control, and providing a default implementation for quick starts. Existing connectors on the now-unmaintained Delta Standalone library are recommended to migrate to Delta Kernel. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Questions this post answers ### Is Delta Standalone deprecated and should I migrate to Delta Kernel? Delta Standalone is no longer maintained and is soon to be deprecated. Existing connectors built on Delta Standalone are strongly recommended to migrate to Delta Kernel, which provides stable high-level Table and Engine APIs in Java and Rust, abstracting away protocol details like deletion vectors, column mapping, and partition columns so connectors can upgrade to support new Delta features without rewrites. _Track migrations like Delta Standalone to Delta Kernel as they land, with daily.dev surfacing the ecosystem's follow-up posts._ ### What performance improvement did the Apache Flink Delta connector get from Delta Kernel? A partial migration to Delta Kernel Java gave the Apache Flink Delta connector a 45x startup time improvement. This was achieved even before a full migration, illustrating how offloading protocol-handling logic to Kernel's stable APIs can significantly reduce connector overhead compared to hand-rolled protocol implementations. _Compare connector performance gains like this when evaluating Delta Lake tooling on daily.dev._ ### When were Delta Kernel read and write APIs released for Java and Rust? Delta Kernel Java read APIs (the Scan class) were first released in Delta 3.0 and have largely stabilized, while write APIs were first released in Delta 3.2 and are still evolving. The Delta Kernel Rust APIs had their read APIs released starting at version 0.1, with write support developing afterward. _Keep track of Delta Kernel API maturity across releases before building on daily.dev._ ## Similar posts on daily.dev - [Delta Kernel \(Rust\) and the future of the Lakehouse.](https://daily.dev/posts/delta-kernel-rust-and-the-future-of-the-lakehouse--twurulaae) · Confessions of a Data Guy · 0 upvotes · 0 comments - [Integrating the Rust Delta Kernel into ClickHouse](https://daily.dev/posts/integrating-the-rust-delta-kernel-into-clickhouse-7vmienqtj) · ClickHouse · 3 upvotes · 0 comments - [Advancing the Open Lakehouse with Apache Spark, the Delta Kernel, and the new UC Delta APIs](https://daily.dev/posts/advancing-the-open-lakehouse-with-apache-spark-the-delta-kernel-and-the-new-uc-delta-apis-dbaazlwws) · Delta Lake Blog · 0 upvotes · 0 comments - [Expanded interoperability with Unity Catalog Open APIs](https://daily.dev/posts/expanded-interoperability-with-unity-catalog-open-apis-ylb6t6p7m) · databricks · 0 upvotes · 0 comments - [Confluent Tableflow \+ Databricks Unity Catalog](https://daily.dev/posts/confluent-tableflow-databricks-unity-catalog-3l7atiiei) · Confluent Blog · 1 upvotes · 0 comments --- Tags: [#rust](https://daily.dev/tags/rust), [#data-engineering](https://daily.dev/tags/data-engineering), [#apache-spark](https://daily.dev/tags/apache-spark) [View this post on daily.dev](https://daily.dev/posts/delta-kernel---building-delta-lake-connectors-made-simple-7wypt0yda) ```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":"Delta Kernel - Building Delta Lake connectors, made simple","url":"https://daily.dev/posts/delta-kernel---building-delta-lake-connectors-made-simple-7wypt0yda","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/delta-kernel---building-delta-lake-connectors-made-simple-7wypt0yda"},"datePublished":"2026-08-16T08:53:33.136Z","dateModified":"2026-08-16T08:55:46.064Z","description":"Delta Kernel is a set of libraries (Java and Rust, the latter with C/C++ bindings) designed to simplify building connectors for Delta Lake tables by...","image":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/3d261be2ab7965496e86322d9cdc753f?_a=AQAEuop","thumbnailUrl":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/3d261be2ab7965496e86322d9cdc753f?_a=AQAEuop","isAccessibleForFree":true,"articleSection":"Delta Lake 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":"Delta Lake Blog","logo":"https://media.daily.dev/image/upload/s--7f2q9Asf--/f_auto,q_auto/v1786870393/logos/delta-lake?_a=BAMAMicg0","url":"https://daily.dev/sources/delta-lake"},"commentCount":0,"discussionUrl":"https://daily.dev/posts/delta-kernel---building-delta-lake-connectors-made-simple-7wypt0yda","interactionStatistic":[{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":0},{"@type":"InteractionCounter","interactionType":{"@type":"CommentAction"},"userInteractionCount":0}],"keywords":"rust,data-engineering,apache-spark","timeRequired":"PT13M"} {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://daily.dev"},{"@type":"ListItem","position":2,"name":"Delta Lake Blog","item":"https://daily.dev/sources/delta-lake"},{"@type":"ListItem","position":3,"name":"Delta Kernel - Building Delta Lake connectors, made simple"}]} {"@context":"https://schema.org","@type":"FAQPage","@id":"https://daily.dev/posts/delta-kernel---building-delta-lake-connectors-made-simple-7wypt0yda#faq","mainEntity":[{"@type":"Question","name":"Is Delta Standalone deprecated and should I migrate to Delta Kernel?","acceptedAnswer":{"@type":"Answer","text":"Delta Standalone is no longer maintained and is soon to be deprecated. 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