What causes "Invalid JSON in the ChatOpenAI's BaseOptions: " in FlowiseAI/Flowise?

Validate the baseOptions string with JSON.parse before submitting.

FlowiseAI/Flowise · error · Error

Invalid JSON in the ChatOpenAI's BaseOptions:

Error message

Invalid JSON in the ChatOpenAI's BaseOptions:

What it means

Same JSON.parse branch as OpenAIEmbedding, in the Custom variant. The message text says "ChatOpenAI's" but the node is an embeddings node (OpenAIEmbeddings) — the string is a copy-paste artifact and does not change behavior.

Source

Thrown at packages/components/nodes/embeddings/OpenAIEmbeddingCustom/OpenAIEmbeddingCustom.ts:132

        const openAIApiKey = getCredentialParam('openAIApiKey', credentialData, nodeData)

        const obj: Partial<OpenAIEmbeddingsParams> & { openAIApiKey?: string; configuration?: ClientOptions } = {
            openAIApiKey
        }

        if (stripNewLines) obj.stripNewLines = stripNewLines
        if (batchSize) obj.batchSize = parseInt(batchSize, 10)
        if (timeout) obj.timeout = parseInt(timeout, 10)
        if (modelName) obj.modelName = modelName
        if (dimensions) obj.dimensions = parseInt(dimensions, 10)
        if (encodingFormat) obj.encodingFormat = encodingFormat

        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 model = new OpenAIEmbeddings(obj)
        return model
    }
}

module.exports = { nodeClass: OpenAIEmbeddingCustom_Embeddings }

View on GitHub (pinned to abe4a8601a)

Solutions

Validate the baseOptions string with JSON.parse before submitting.
Supply baseOptions as an object so the parse branch is skipped.
If debugging, ignore the misleading 'ChatOpenAI' wording and treat as an embeddings BaseOptions error.

Example fix

// before
{ baseURL: 'http://localhost:8000/v1' }
// after
{"baseURL":"http://localhost:8000/v1"}

Defensive patterns

Strategy: validation

Validate before calling

function parseBaseOptions(raw: unknown): Record<string, unknown> | undefined {
  if (raw == null) return undefined
  if (typeof raw === 'object') return raw as Record<string, unknown>
  if (typeof raw === 'string') JSON.parse(raw)
  return undefined
}

Type guard

function isJsonString(v: string): v is string {
  try { JSON.parse(v); return true } catch { return false }
}

Try / catch

try {
  parsedBaseOptions = typeof baseOptions === 'object' ? baseOptions : JSON.parse(baseOptions)
} catch (e) {
  throw new Error(`BaseOptions (embeddings) is not valid JSON: ${(e as Error).message}`)
}

Prevention

Remember the message says 'ChatOpenAI' but the node is embeddings - validate the embeddings BaseOptions.
Pass an object to skip the parse branch.
Lint the JSON before saving the node.
Avoid JS object-literal syntax in the field.

When it happens

Trigger: Custom OpenAI-compatible endpoint node receives a baseOptions string that fails JSON.parse (trailing comma, single quotes, malformed JSON).

Common situations: Pasting a JS object literal into the BaseOptions field; quote-style mismatch; using a custom OpenAI-compatible provider with extra headers supplied as a malformed string.

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/0a45799b400080cd. Report an issue: GitHub.