POST /precheckAssets

For most use cases, the slideless CLI handles the upload flow end-to-end — you rarely need to call this endpoint directly. This reference is for custom tooling that can’t run Node.

The three-step upload flow

Slideless uses a content-addressed upload protocol. Each file is stored by its SHA-256 hash, so unchanged files across deck versions dedupe automatically.

POST /precheckAssets — send hashes, get back which ones are missing. (This page.)
POST /uploadPresentationAsset — upload each missing blob (multipart, streamed).
POST /commitPresentationVersion — commit the manifest, bump the version.

Endpoint

POST https://europe-west1-slideless-ai.cloudfunctions.net/precheckAssets

Auth

Header	Value
`Authorization`	`Bearer cko_…` (or `cka_…`)
`Content-Type`	`application/json`

Required scope: presentations:write.

Request body

Field	Type	Required	Description
`hashes`	`string[]`	yes	SHA-256 hashes (64 lowercase hex chars each). Max 2000 per call.
`presentationId`	string	no	Check against this existing presentation’s blob store. Requires ownership.
`sessionId`	string	no	Carry a session from a prior call. Mutually exclusive with `presentationId`.

Call patterns:

New presentation (first call): omit both presentationId and sessionId. Response includes sessionId + reserved presentationId to use for uploadPresentationAsset and commitPresentationVersion.
Update existing presentation: pass presentationId. Backend checks dedup against that presentation’s blob store.
Subsequent calls in a new-presentation flow: pass the sessionId you got from the first call.

Example:

{
  "hashes": [
    "4edd6a4b20278337c9cd35ef2b71e375522abd1c7563301dca7eebac31b5665e",
    "c3d6ce7c672be2d98d555bed4504b944c9730ec33baf35b778cc049cf928ccb0"
  ]
}

Response (200)

New-presentation flow (no presentationId in request)

{
  "success": true,
  "data": {
    "missing": [
      "4edd6a4b20278337c9cd35ef2b71e375522abd1c7563301dca7eebac31b5665e",
      "c3d6ce7c672be2d98d555bed4504b944c9730ec33baf35b778cc049cf928ccb0"
    ],
    "sessionId": "019dba77-...",
    "presentationId": "019dba77-4a1d-716e-8993-61e7c5771a7b"
  }
}

Update flow (presentationId in request)

{
  "success": true,
  "data": {
    "missing": ["c3d6ce7c672be2d98d555bed4504b944c9730ec33baf35b778cc049cf928ccb0"]
  }
}

Field	Description
`missing`	Subset of input hashes that need uploading. Everything else is already in the store.
`sessionId`	Only present on new-presentation flow. Pass on subsequent calls. Sessions auto-expire after 1 hour.
`presentationId`	Only present on new-presentation flow. The reserved presentationId for the final commit.

Errors

Status	Code	Cause
`400`	`invalid-argument`	`hashes` isn’t an array, >2000 entries, or entries don’t match the sha256 regex
`401`	`unauthenticated`	Missing/invalid API key
`403`	`permission-denied`	Key lacks `presentations:write`, or caller is not the owner or an active dev collaborator
`404`	`not-found`	`presentationId` or `sessionId` doesn’t exist (sessions expire after 1 hour)

POST /uploadPresentationAsset — upload missing blobs (step 2).
POST /commitPresentationVersion — commit the manifest (step 3).

CLI auth endpoints

POST /uploadPresentationAsset

Getting Started

Why Slideless

Concepts

CLI

Guides

Plugin Skills

Claude Desktop (MCP)

Advanced: HTTP API

The three-step upload flow

Endpoint

Auth

Request body

Response (200)

New-presentation flow (no presentationId in request)

Update flow (presentationId in request)

Errors

Next

​The three-step upload flow

​Endpoint

​Auth

​Request body

​Response (200)

​New-presentation flow (no presentationId in request)

​Update flow (presentationId in request)

​Errors

​Next

The three-step upload flow

Endpoint

Auth

Request body

Response (200)

New-presentation flow (no presentationId in request)

Update flow (presentationId in request)

Errors

Next