--- title: OpenAPI Overlays for Adding Tool-Specific Content... description: OpenAPI Overlays solve the problem of vendor-specific extensions polluting canonical API specs. Instead of embedding tool-specific metadata like AWS API... canonical: https://daily.dev/posts/openapi-overlays-for-adding-tool-specific-content-without-polluting-the-spec-np7suyu3c twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: OpenAPI Overlays for Adding Tool-Specific Content Without Polluting the Spec | daily.dev og:description: OpenAPI Overlays solve the problem of vendor-specific extensions polluting canonical API specs. Instead of embedding tool-specific metadata like AWS API... og:url: https://daily.dev/posts/openapi-overlays-for-adding-tool-specific-content-without-polluting-the-spec-np7suyu3c og:image: https://api.daily.dev/og/posts/Np7Suyu3c.png og:image:alt: OpenAPI Overlays for Adding Tool-Specific Content Without Polluting the Spec 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. # OpenAPI Overlays for Adding Tool-Specific Content Without Polluting the Spec **[API Evangelist](https://daily.dev/sources/apievangelist)** · 4 min read · 0 upvotes · 0 comments ## Summary OpenAPI Overlays solve the problem of vendor-specific extensions polluting canonical API specs. Instead of embedding tool-specific metadata like AWS API Gateway integration blocks or Speakeasy SDK naming hints directly into the source OpenAPI definition, overlays let you define those modifications in separate documents that are applied at build time. Each tool gets its own overlay file that references the canonical spec via an `extends` field and uses JSONPath targets to inject vendor extensions. This keeps the source spec clean, makes tool migrations easier, and ensures the canonical definition remains a true contract rather than a build artifact. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Similar posts on daily.dev - [OpenAPI Overlays for Separation of Concerns When You Do Not Own the Spec](https://daily.dev/posts/openapi-overlays-for-separation-of-concerns-when-you-do-not-own-the-spec-zhy9th4pq) · API Evangelist · 0 upvotes · 0 comments - [The Many Use Cases for OpenAPI Overlays](https://daily.dev/posts/the-many-use-cases-for-openapi-overlays-1gjpvrair) · API Evangelist · 0 upvotes · 0 comments - [OpenAPI Overlays for Visual Authoring Without Hand-Writing JSONPath](https://daily.dev/posts/openapi-overlays-for-visual-authoring-without-hand-writing-jsonpath-bfli4fhdw) · API Evangelist · 0 upvotes · 0 comments - [OpenAPI Overlays for SDK Generation Prep: Fixing a Spec Before Codegen](https://daily.dev/posts/openapi-overlays-for-sdk-generation-prep-fixing-a-spec-before-codegen-djq72gnix) · API Evangelist · 0 upvotes · 0 comments - [OpenAPI Overlays for Improving Developer Experience: Enriching a Thin, Code-Generated Spec](https://daily.dev/posts/openapi-overlays-for-improving-developer-experience-enriching-a-thin-code-generated-spec-qiejsxc37) · API Evangelist · 0 upvotes · 0 comments --- Tags: [#architecture](https://daily.dev/tags/architecture), [#api-gateway](https://daily.dev/tags/api-gateway), [#openapi](https://daily.dev/tags/openapi) [View this post on daily.dev](https://daily.dev/posts/openapi-overlays-for-adding-tool-specific-content-without-polluting-the-spec-np7suyu3c) ```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":"OpenAPI Overlays for Adding Tool-Specific Content Without Polluting the Spec","url":"https://daily.dev/posts/openapi-overlays-for-adding-tool-specific-content-without-polluting-the-spec-np7suyu3c","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/openapi-overlays-for-adding-tool-specific-content-without-polluting-the-spec-np7suyu3c"},"datePublished":"2026-07-12T12:35:03.808Z","dateModified":"2026-07-12T12:35:24.120Z","description":"OpenAPI Overlays solve the problem of vendor-specific extensions polluting canonical API specs. 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