> For the complete documentation index, see [llms.txt](https://docs.viesus.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.viesus.com/reference/cloud-api.md).

# Cloud API

VIESUS Cloud GraphQL API reference — authentication, uploading, image and PDF enhancement, credits, and webhooks.

The VIESUS Cloud API is a hosted GraphQL service for image and PDF enhancement. No server to manage, no GUID to bind, no GPU to procure — upload, enhance, download. Billed per image via a credit system, with a free tier for evaluation.

Use the Cloud API when you don't want to operate your own infrastructure, when you need on-demand AI upscaling without a local GPU, or to add VIESUS to a frontend that already calls other cloud APIs.

<table data-view="cards"><thead><tr><th></th><th></th><th data-hidden data-card-target data-type="content-ref"></th></tr></thead><tbody><tr><td><h4>Overview</h4></td><td>What the Cloud API offers, when to use it vs on-premise, and the GraphQL endpoint.</td><td><a href="/reference/cloud-api/overview.md">Overview</a></td></tr><tr><td><h4>Authentication</h4></td><td>API keys, header conventions, and how to manage authentication for production.</td><td><a href="/reference/cloud-api/authentication.md">Authentication</a></td></tr><tr><td><h4>Uploading</h4></td><td>Multipart upload, file size limits, supported formats, and signed URLs.</td><td><a href="/reference/cloud-api/uploading.md">Uploading</a></td></tr><tr><td><h4>Enhance Images</h4></td><td>The image enhancement mutation: parameters, options, response shape, async behavior.</td><td><a href="/reference/cloud-api/image-enhancement.md">Enhance Images</a></td></tr><tr><td><h4>Enhance PDFs</h4></td><td>PDF enhancement endpoint, page selection, and result retrieval.</td><td><a href="/reference/cloud-api/pdf-enhancement.md">Enhance PDFs</a></td></tr><tr><td><h4>Credits</h4></td><td>How credits are consumed, free tier limits, and how to top up.</td><td><a href="/reference/cloud-api/credits.md">Credits</a></td></tr><tr><td><h4>Webhooks</h4></td><td>Async notification on enhancement completion — payload format, retries, and signing.</td><td><a href="/reference/cloud-api/webhooks.md">Webhooks</a></td></tr></tbody></table>


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