FlowiseAI/Flowise · error · Error

Invalid base URL: must be a valid URL

Error message

Invalid base URL: must be a valid URL

What it means

Thrown in AgentAsTool_Tools.init when baseURL is falsy or fails isValidURL. baseURL is the host of the agentflow HTTP API; it falls back to options.baseURL, so the error means neither the node input nor the server default is a usable absolute URL. Without a valid base the tool cannot construct the fetch target.

Source

Thrown at packages/components/nodes/tools/AgentAsTool/AgentAsTool.ts:177

        const overrideConfig =
            typeof nodeData.inputs?.overrideConfig === 'string' &&
            nodeData.inputs.overrideConfig.startsWith('{') &&
            nodeData.inputs.overrideConfig.endsWith('}')
                ? JSON.parse(nodeData.inputs.overrideConfig)
                : nodeData.inputs?.overrideConfig

        const startNewSession = nodeData.inputs?.startNewSession as boolean

        const baseURL = (nodeData.inputs?.baseURL as string) || (options.baseURL as string)

        // Validate agentflowid is a valid UUID
        if (!selectedAgentflowId || !isValidUUID(selectedAgentflowId)) {
            throw new Error('Invalid agentflow ID: must be a valid UUID')
        }

        // Validate baseURL is a valid URL
        if (!baseURL || !isValidURL(baseURL)) {
            throw new Error('Invalid base URL: must be a valid URL')
        }

        const credentialData = await getCredentialData(nodeData.credential ?? '', options)
        const agentflowApiKey = getCredentialParam('agentflowApiKey', credentialData, nodeData)

        if (selectedAgentflowId === options.chatflowid) throw new Error('Cannot call the same agentflow!')

        let headers = {}
        if (agentflowApiKey) headers = { Authorization: `Bearer ${agentflowApiKey}` }

        let toolInput = ''
        if (useQuestionFromChat) {
            toolInput = input
        } else if (customInput) {
            toolInput = customInput
        }

        let name = _name || 'agentflow_tool'

View on GitHub (pinned to abe4a8601a)

Solutions

1. Set inputs.baseURL to an absolute URL including scheme, e.g. https://app.example.com.
2. If relying on the server default, ensure the server's BASE_URL/config is set and propagated into options.baseURL.
3. Strip any trailing slash or path from baseURL — only the origin should be configured.

Example fix

// before
const baseURL = (nodeData.inputs?.baseURL as string) || (options.baseURL as string)
// after
const rawBase = (nodeData.inputs?.baseURL as string) || (options.baseURL as string)
const baseURL = rawBase ? new URL(rawBase).origin : ''
if (!baseURL || !isValidURL(baseURL)) {
  throw new Error('Invalid base URL: must be a valid URL')
}

import { isValidURL } from '../../../src/validator'
function resolveBaseURL(node: INodeData, options: ICommonObject): string {
  const raw = (node.inputs?.baseURL as string) || (options.baseURL as string)
  const base = raw ? new URL(raw).origin : ''
  if (!base || !isValidURL(base)) throw new Error('Invalid base URL: must be a valid URL')
  return base
}

function isAbsoluteUrl(v: unknown): v is string {
  if (typeof v !== 'string') return false
  try { new URL(v); return true } catch { return false }
}

When it happens

Trigger: Node inputs.baseURL is empty AND options.baseURL is undefined (e.g. running outside the normal server context, or in a test harness); baseURL was entered as a hostname without scheme ('localhost:3000') or with a trailing path that breaks URL composition.

Common situations: Self-hosted deployment where BASE_URL env var was not set; behind a reverse proxy and the configured URL used http vs https inconsistently; local dev entered 'localhost:3000' instead of 'http://localhost:3000'.

Related errors

• Model is required
• Invalid Flow State
• Tool not selected
• Invalid agentflow ID: must be a valid UUID
• Invalid base URL: must be a valid URL

AI-assisted analysis of FlowiseAI/Flowise@abe4a8601a (2026-08-12). Data as JSON: /api/errors/7f1a9d01e3d4c3ba. Report an issue: GitHub.