Grok Imagine base64 response_format vs a Sume hosted URL

With xAI directly you choose the output with response_format: the default is url (temporary hosted URLs) and requesting base64 embeds the image so you do not download it. On Sume there is no such switch in the image docs; results come back as Sume-hosted URLs in data[].url.

Sources: xAI's image generation page and Sume's image docs, read 2026-10-01.

What does xAI offer?

The xAI page describes url as the default, returning temporary hosted URLs, and base64 as the way to embed images directly without downloading them. Pick base64 when you want bytes in the response and URL when you would rather fetch later.

What does a Sume call return instead?

The Sume docs say images "return as Sume-hosted URLs with usage data", and the specifics table puts it this way: data[].url (Sume-hosted, signed) rather than inline base64. Sume already mirrors generated media, and URLs keep responses small.

How do I get bytes from the URL?

Fetch data[].url and store the file in your own storage if you need a permanent copy of the bytes. Do not paste signed URLs into logs or chat. Calls that outlast the 30-second blocking wait return a job envelope with 202, and you read the images from the job result.

Will response_format be rejected?

Treat it as unsupported. Sume's rule is that a parameter the selected model does not list is rejected with 400 unsupported_parameter. Check GET /v1/images/models for what x-ai/grok-image lists, and see the Grok image overview for the rest of the contract.