FlowiseAI/Flowise · critical · Error

Failed to load OpenAPI spec

Error message

Failed to load OpenAPI spec

What it means

Thrown by OpenAPIToolkit.init when loadOpenApiSpec returns a falsy value, meaning the spec could not be resolved from either a uploaded file (openApiFile) or a remote link (openApiLink) given the chosen inputType. The toolkit needs a parsed OpenAPI document to dereference with $RefParser and to derive tools, so a null/empty spec aborts initialization.

Source

Thrown at packages/components/nodes/tools/OpenAPIToolkit/OpenAPIToolkit.ts:144

        const inputType = nodeData.inputs?.inputType as string
        const openApiFile = nodeData.inputs?.openApiFile as string
        const openApiLink = nodeData.inputs?.openApiLink as string
        const selectedServer = nodeData.inputs?.selectedServer as string
        const customCode = nodeData.inputs?.customCode as string
        const _headers = nodeData.inputs?.headers as string
        const removeNulls = nodeData.inputs?.removeNulls as boolean

        const headers = typeof _headers === 'object' ? _headers : _headers ? JSON.parse(_headers) : {}

        const specData = await this.loadOpenApiSpec(
            {
                inputType,
                openApiFile,
                openApiLink
            },
            options
        )
        if (!specData) throw new Error('Failed to load OpenAPI spec')

        const _data: any = await $RefParser.dereference(specData)

        // Use selected server or fallback to first server
        let baseUrl: string
        if (selectedServer && selectedServer !== 'error') {
            baseUrl = selectedServer
        } else {
            baseUrl = _data.servers?.[0]?.url
        }

        if (!baseUrl) throw new Error('OpenAPI spec does not contain a server URL')

        const appDataSource = options.appDataSource as DataSource
        const databaseEntities = options.databaseEntities as IDatabaseEntity
        const variables = await getVars(appDataSource, databaseEntities, nodeData, options)
        const flow = { chatflowId: options.chatflowid }

View on GitHub (pinned to abe4a8601a)

Solutions

1. Confirm inputType matches the field you populated: 'file' with openApiFile, 'link' with openApiLink.
2. If using a link, open it in a browser to confirm it is reachable and returns valid OpenAPI YAML/JSON.
3. If using a file, re-upload the spec and confirm it persisted.
4. Check that the link is not blocked by network policy, proxy, or auth; mirror the spec locally if needed.
5. Validate the spec with a linter (e.g. Swagger Editor) to ensure it is well-formed before this node runs.

Example fix

// before
nodeData.inputs = { inputType: 'link', openApiLink: '' }
// after
nodeData.inputs = { inputType: 'link', openApiLink: 'https://petstore.swagger.io/v2/swagger.json' }

async function specIsLoadable(inputType: string, openApiFile: string, openApiLink: string): Promise<boolean> {
  if (inputType === 'file') return Boolean(openApiFile)
  if (inputType === 'link') {
    if (!openApiLink) return false
    try {
      const res = await fetch(openApiLink)
      return res.ok
    } catch { return false }
  }
  return false
}

function hasSpecInput(i: unknown): i is { inputType: string; openApiFile?: string; openApiLink?: string } {
  return typeof i === 'object' && i !== null && typeof (i as any).inputType === 'string'
    && (((i as any).inputType === 'file' && (i as any).openApiFile) || ((i as any).inputType === 'link' && (i as any).openApiLink))
}

try {
  const tools = await toolkit.init(nodeData, '', options)
} catch (e) {
  if (e instanceof Error && e.message === 'Failed to load OpenAPI spec') {
    // verify inputType matches the populated field, re-check link/file
  } else throw e
}

When it happens

Trigger: inputType set to 'link' but openApiLink is empty or returns 404; inputType set to 'file' but openApiFile is empty or the file was deleted; network/proxy blocking the remote fetch; the uploaded spec file failed to persist in storage; inputType mismatched the field that was actually filled.

Common situations: User selected the wrong inputType (e.g. 'link' while only uploading a file); the OpenAPI URL is behind auth or a corporate proxy; the spec file upload silently failed; a typo in the URL; the spec is YAML that failed JSON parsing before this check.

Related errors

• OpenAPI spec does not contain a server URL
• JSON Path is required
• No Jira host provided
• Model is required
• Invalid Flow State

AI-assisted analysis of FlowiseAI/Flowise@abe4a8601a (2026-08-12). Data as JSON: /api/errors/48cebe9b5ddae04f. Report an issue: GitHub.