API Documentation

API Reference

The 5sync API is a RESTful interface for managing your files, links, and account programmatically. All requests are made to the following base URL:

Base URL

https://5sync.com/v1

All responses are returned as JSON. Authentication is required for every request.

Authentication

Authenticate by including your API key in the Authorization header as a Bearer token. API keys start with the prefix sk_5s_.

Authorization Header

Authorization: Bearer sk_5s_...

You can generate and manage API keys from Settings → Developer → API Keys in your 5sync dashboard. Keep your keys secret and never expose them in client-side code.

Rate Limits

API rate limits depend on your plan. Limits are applied per API key on a rolling one-hour window.

Plan	Requests / Hour
Starter	60
Plus	600
Business	6,000

Rate limit status is returned in every response via headers:

X-RateLimit-Limit — Maximum requests per hour
X-RateLimit-Remaining — Requests remaining in current window
X-RateLimit-Reset — Unix timestamp when window resets

When you exceed the limit, the API returns 429 Too Many Requests:

429 Response

{
  "error": {
    "type": "rate_limit_exceeded",
    "message": "Rate limit exceeded. Try again in 42 seconds."
  }
}

PUT /v1/files

Upload a single file. For files larger than 100 MB, use the Multipart Upload endpoint instead.

Parameter	Type	Required	Description
`file`	File	required	The file to upload (multipart/form-data)
`path`	string	optional	Destination path (e.g. `/documents`)
`encrypt`	boolean	optional	Enable encryption. Default: `true`

Example Request

curl -X PUT https://5sync.com/v1/files \
  -H "Authorization: Bearer sk_5s_..." \
  -F "file=@report.pdf" \
  -F "path=/documents" \
  -F "encrypt=true"

Response — 201 Created

{
  "id": "f_8kx2m",
  "name": "report.pdf",
  "size": 1048576,
  "encrypted": true,
  "created": "2025-02-10T14:22:00Z"
}

POST /v1/files/multipart

Upload large files in chunks using a three-step process: initialize, upload parts, then complete.

Step 1 — Initialize

POST /v1/files/multipart/init

Parameter	Type	Required	Description
`filename`	string	required	Name of the file being uploaded
`size`	integer	required	Total file size in bytes
`parts`	integer	required	Number of chunks to split the upload into

Response — 200 OK

{
  "upload_id": "up_abc",
  "chunk_size": 5242880,
  "expires": "2025-02-10T15:22:00Z"
}

Step 2 — Upload Part

PUT /v1/files/multipart/:upload_id/:part

Send the binary data for each chunk. The :part parameter is a zero-based index.

Response — 200 OK

{
  "part": 0,
  "received": true
}

Step 3 — Complete

POST /v1/files/multipart/:upload_id/complete

Once all parts are uploaded, finalize the multipart upload. The response returns the full file object.

Response — 201 Created

{
  "id": "f_8kx2m",
  "name": "report.pdf",
  "size": 1048576,
  "encrypted": true,
  "created": "2025-02-10T14:22:00Z"
}

GET /v1/files/:id

Retrieve metadata for a single file, or download the file contents.

Parameter	Type	Required	Description
`download`	boolean	optional	If `true`, returns the file binary instead of metadata

Example Request

curl https://5sync.com/v1/files/f_8kx2m \
  -H "Authorization: Bearer sk_5s_..."

Response — 200 OK

{
  "id": "f_8kx2m",
  "name": "report.pdf",
  "size": 1048576,
  "mime_type": "application/pdf",
  "path": "/documents",
  "encrypted": true,
  "versions": 3,
  "created": "2025-02-10T14:22:00Z",
  "modified": "2025-02-11T09:15:00Z"
}

GET /v1/files

List files in your account with optional filtering, pagination, and sorting.

Parameter	Type	Required	Description
`path`	string	optional	Filter by directory path
`page`	integer	optional	Page number (default: `1`)
`limit`	integer	optional	Items per page, max `100` (default: `20`)
`order_by`	string	optional	Sort field: `name`, `created`, `size`

Response — 200 OK

{
  "items": [...],
  "total": 87,
  "page": 1,
  "limit": 20
}

DELETE /v1/files/:id

Permanently delete a file. This action cannot be undone.

Example Request

curl -X DELETE https://5sync.com/v1/files/f_8kx2m \
  -H "Authorization: Bearer sk_5s_..."

Response — 200 OK

{
  "deleted": true
}

POST /v1/links

Create a shareable link for a file. Optionally add password protection, expiry, and download controls.

Parameter	Type	Required	Description
`file_id`	string	required	ID of the file to share
`password`	string	optional	Password-protect the link
`ttl_hours`	integer	optional	Hours until the link expires
`allow_download`	boolean	optional	Allow file download via the link. Default: `true`

Example Request

curl -X POST https://5sync.com/v1/links \
  -H "Authorization: Bearer sk_5s_..." \
  -H "Content-Type: application/json" \
  -d '{"file_id":"f_8kx2m","ttl_hours":168}'

Response — 201 Created

{
  "id": "lnk_3fa",
  "url": "https://5sync.com/s/abc123",
  "expires": "2025-02-17T14:22:00Z"
}

GET /v1/changes

Retrieve a feed of file events (created, modified, deleted) since a given timestamp. Useful for building sync clients.

Parameter	Type	Required	Description
`since`	string	required	ISO 8601 timestamp to fetch changes from
`path`	string	optional	Filter changes to a specific directory path

Example Request

curl "https://5sync.com/v1/changes?since=2025-02-10T00:00:00Z" \
  -H "Authorization: Bearer sk_5s_..."

Response — 200 OK

{
  "events": [
    {
      "id": "f_8kx2m",
      "action": "created",
      "timestamp": "2025-02-10T14:22:00Z"
    },
    {
      "id": "f_9yz3n",
      "action": "modified",
      "timestamp": "2025-02-10T14:35:00Z"
    }
  ],
  "cursor": "c_next123",
  "has_more": false
}

Errors

The API uses standard HTTP status codes. All error responses follow a consistent format:

Error Format

{
  "error": {
    "type": "unauthorized",
    "message": "Invalid or expired API key."
  }
}

Status	Type	Description
`400`	bad_request	The request was malformed or missing required parameters
`401`	unauthorized	Invalid or missing API key
`403`	forbidden	API key does not have permission for this action
`404`	not_found	The requested resource does not exist
`429`	rate_limit_exceeded	Too many requests — see Rate Limits
`500`	internal_error	Unexpected server error — please retry or contact support