gatsbyjs/gatsby · error

There was an error compiling the html.js component for the d

Error message

There was an error compiling the html.js component for the development server.
See our docs page on debugging HTML builds for help https://gatsby.dev/debug-html

What it means

Fires in createIndexHtml when the develop-HTML webpack build throws a WebpackError (non-webpack errors are re-panicked unchanged): it flags a compile-time failure of the dev server's html.js renderer, not a runtime page error.

Source

Thrown at packages/gatsby/src/utils/start-server.ts:113

        program,
        Stage.DevelopHTML,
        activity.span
      )
      await doBuildPages(
        rendererPath,
        [`/`],
        activity,
        workerPool,
        Stage.DevelopHTML
      )
      // close the compiler
      await close()
    } catch (err) {
      if (err.name !== `WebpackError`) {
        report.panic(err)
        return
      }
      report.panic(
        report.stripIndent`
          There was an error compiling the html.js component for the development server.
          See our docs page on debugging HTML builds for help https://gatsby.dev/debug-html
        `,
        err
      )
    }
  }
  const indexHTMLActivity = report.phantomActivity(`building index.html`, {})

  let pageRenderer: string
  if (process.env.GATSBY_EXPERIMENTAL_DEV_SSR) {
    const { buildRenderer } = require(`../commands/build-html`)
    pageRenderer = (await buildRenderer(program, Stage.DevelopHTML))
      .rendererPath
    const { initDevWorkerPool } = require(`./dev-ssr/render-dev-html`)
    initDevWorkerPool()
  } else {

View on GitHub (pinned to e85d62f177)

Solutions

1. Follow the debugging guide at https://gatsby.dev/debug-html
2. Fix the component/code error reported by webpack in the HTML build (often in gatsby-ssr or invalid SSR output from a page/component)

When it happens

Trigger: Thrown at packages/gatsby/src/utils/start-server.ts:113 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of gatsbyjs/gatsby@e85d62f177 (2026-08-26). Data as JSON: /api/errors/40c0ecf0a5b953fb. Report an issue: GitHub.