{"record":{"id":"6dded0c0f17adb64","repo":"facebook/react","slug":"the-body-tag-may-only-be-rendered-once","errorCode":null,"errorMessage":"The `` tag may only be rendered once.","messagePattern":"The `` tag may only be rendered once\\.","errorType":"exception","errorClass":"Error","httpStatus":null,"severity":"error","filePath":"packages/react-dom-bindings/src/server/ReactFizzConfigDOM.js","lineNumber":3774,"sourceCode":" // This is deep and is likely just an error. we emit it inline though.\n // Validation should warn that this tag is the the wrong spot.\n return pushStartGenericElement(target, props, 'head', formatContext);\n }\n}\n\nfunction pushStartBody(\n target: Array,\n props: Object,\n renderState: RenderState,\n preambleState: null | PreambleState,\n formatContext: FormatContext,\n): ReactNodeList {\n if (formatContext.insertionMode < HTML_MODE) {\n // This is the Document.body\n const preamble = preambleState || renderState.preamble;\n\n if (preamble.bodyChunks) {\n throw new Error(`The ${'``'} tag may only be rendered once.`);\n }\n\n // Insert a marker in the body where the contribution to the body tag was in case we need to clear it.\n if (preambleState !== null) {\n target.push(bodyPreambleContributionChunk);\n }\n\n preamble.bodyChunks = [];\n return pushStartSingletonElement(\n preamble.bodyChunks,\n props,\n 'body',\n formatContext,\n );\n } else {\n // This is deep and is likely just an error. we emit it inline though.\n // Validation should warn that this tag is the the wrong spot.\n return pushStartGenericElement(target, props, 'body', formatContext);","sourceCodeStart":3756,"sourceCodeEnd":3792,"githubUrl":"https://github.com/facebook/react/blob/eafeac097ba51e1eab809c07102126bd5f8e5425/packages/react-dom-bindings/src/server/ReactFizzConfigDOM.js#L3756-L3792","documentation":"Thrown by pushStartBody when a second document-level begins rendering (preamble.bodyChunks already populated and insertionMode < HTML_MODE). HTML permits exactly one body element; the first claims the preamble slot and any later one aborts the render.","triggerScenarios":"A tree containing two elements at document level — e.g. ... in the layout plus another rendered by a page, a portal target markup string, or an imported legacy component.","commonSituations":"Merging an existing full HTML page component into an app that already provides /; copy-pasting standalone page templates (with their own ) into framework layouts; third-party widgets shipping full-document markup.","solutions":["Keep only in the root layout and render everything else as fragments or regular elements","Convert pasted full-page components: strip their // wrappers down to the inner content","Grep the render output/tree for 'Hi
\n\n// after: layout owns the body; page renders content only\n<> Hi
","handlingStrategy":"validation","validationCode":null,"typeGuard":null,"tryCatchPattern":null,"preventionTips":["Keep exactly one , defined in the root layout","Strip full-document wrappers from pasted page components","Add a lint rule (e.g. react/forbid-elements or custom) banning / outside a designated layout file"],"tags":["ssr","body","preamble","document-structure"],"backgroundTag":"duplicate-document-element","analyzedSha":"eafeac097ba51e1eab809c07102126bd5f8e5425","analyzedAt":"2026-08-21T22:01:08.818Z","schemaVersion":2},"datasetVersion":"2026-08-21T23:17:16.201Z"}