FlowiseAI/Flowise · error · Error

Invalid JSON in the ChatOpenAI's BaseOptions: ${exception}

Error message

Invalid JSON in the ChatOpenAI's BaseOptions: ${exception}

What it means

ChatOpenAI parses the BaseOptions input the same way as the other OpenAI-compatible nodes: if it is a string it is JSON.parse'd, and any SyntaxError is wrapped with this label. The parsed value becomes defaultHeaders under obj.configuration. An object input bypasses parsing.

Source

Thrown at packages/components/nodes/chatmodels/ChatOpenAI/ChatOpenAI.ts:285

            delete obj.temperature
            delete obj.stop
            const reasoning: OpenAIClient.Reasoning = {}
            if (reasoningEffort) {
                reasoning.effort = reasoningEffort
            }
            if (reasoningSummary) {
                reasoning.summary = reasoningSummary
            }
            obj.reasoning = reasoning
        }

        let parsedBaseOptions: any | undefined = undefined

        if (baseOptions) {
            try {
                parsedBaseOptions = typeof baseOptions === 'object' ? baseOptions : JSON.parse(baseOptions)
            } catch (exception) {
                throw new Error("Invalid JSON in the ChatOpenAI's BaseOptions: " + exception)
            }
        }

        if (basePath || parsedBaseOptions) {
            obj.configuration = {
                baseURL: basePath,
                defaultHeaders: parsedBaseOptions
            }
        }

        const multiModalOption: IMultiModalOption = {
            image: {
                allowImageUploads: allowImageUploads ?? false
            }
        }

        const model = new ChatOpenAI(nodeData.id, obj)
        model.setMultiModalOption(multiModalOption)

View on GitHub (pinned to abe4a8601a)

Solutions

Validate the BaseOptions string with a JSON parser before saving the node.
Quote all keys/values with double quotes and drop trailing commas/comments.
Prefer passing the node a plain object (the typeof === 'object' branch skips JSON.parse).
Use a minimal example first ({"X-Custom":"value"}) and extend incrementally to isolate the bad token.

Example fix

// before
{ Authorization: "Bearer x", } // unquoted key + trailing comma -> throws [92]

// after
{ "Authorization": "Bearer x" }

Defensive patterns

Strategy: validation

Validate before calling

function parseBaseOptions(raw) {
  if (!raw) return undefined
  if (typeof raw === 'object') return raw
  try { return JSON.parse(raw) }
  catch (e) { throw new Error(`ChatOpenAI BaseOptions JSON invalid: ${e.message}`) }
}
const parsedBaseOptions = parseBaseOptions(nodeData.inputs?.baseOptions)

Type guard

function isHeadersObject(v: unknown): v is Record<string, string> {
  if (typeof v !== 'object' || v === null || Array.isArray(v)) return false
  return Object.values(v).every(x => typeof x === 'string')
}

Try / catch

try {
  return await initChatOpenAI(nodeData, options)
} catch (e) {
  if (e.message.includes("Invalid JSON in the ChatOpenAI's BaseOptions")) {
    throw new Error('Correct the BaseOptions JSON on the ChatOpenAI node, then redeploy.')
  }
  throw e
}

Prevention

JSON-lint header objects before saving.
Use double quotes; no trailing commas; no comments.
Pass an object literal when building the node in code.
Keep BaseOptions minimal — only headers that OpenAI SDK does not natively accept.

When it happens

Trigger: The ChatOpenAI node's BaseOptions field holds invalid JSON — same shape of mistakes as [91] but on the primary ChatOpenAI node. The throw is reached only when baseOptions is a truthy string that fails to parse.

Common situations: Users configuring custom defaultHeaders (e.g. Helicone, Langfuse, OpenRouter passthrough) paste malformed JSON; copying header objects from Python dict syntax; trailing commas from a relaxed editor; smart quotes from a chat client.

Understand the failure class

Parsing and encoding errors: unexpected token, malformed input — why parsers reject input and how to find the real culprit.

Related errors

AI-assisted analysis of FlowiseAI/Flowise@abe4a8601a (2026-08-12). Data as JSON: /api/errors/6b27cf94f360b7ed. Report an issue: GitHub.