Check whether an email address is available for a new user invitation.

12 May 2026
5 Minutes to read
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Check whether an email address is available for a new user invitation.

Updated on 12 May 2026
5 Minutes to read
Contributors

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Get

/v3/projects/{project_id}/users/email-availability

Returns a boolean indicating whether the given email address can be used for a new user invitation. An email is considered unavailable if it already belongs to an existing user in the project. Set isAnSsoUser to true to restrict the check to SSO-provisioned users only. Call this endpoint before POST /v3/projects/{projectId}/users to avoid invitation failures due to duplicate emails.

Security

OAuth

All V3 endpoints require a Bearer token. Generate tokens in the Document360 portal under Settings > API Tokens. Tokens are project-scoped, require the customerApi scope, and do not expire by default. Tokens can be revoked at any time from the portal. Include the token in every request: Authorization: Bearer <your-token>. Alternatively, use the Authorize button below to sign in via OAuth2 Authorization Code flow with PKCE.

FlowAuthorization Code

Authorization URLhttps://identity.document360.net/connect/authorize

Token URLhttps://identity.document360.net/connect/token

Scopes:

customerApiDocument360 Customer API

Path parameters

project_id

string (uuid) Required

The unique identifier of the project. Retrieve project IDs from GET /v3/projects.

Example9a3b4c5d-6e7f-8a9b-0c1d-2e3f4a5b6c7d

Query parameters

stringRequired

The email address to check for availability before inviting a new user.

is_an_sso_user

boolean

When true, filters the check to only consider SSO users.

Defaultfalse

Responses

200

Email availability checked successfully.

Email is available

The provided email address is not associated with any existing user

{
  "data": {
    "is_available": true
  },
  "success": true,
  "request_id": "d4e5f6a7-b8c9-0123-defa-b34567890123",
  "errors": [],
  "warnings": []
}

Email is taken

The provided email address is already in use by another user

{
  "data": {
    "is_available": false
  },
  "success": true,
  "request_id": "e5f6a7b8-c9d0-1234-efab-c45678901234",
  "errors": [],
  "warnings": []
}

Expand All

object

Generic API response wrapper containing typed data.

data

object

Response data payload.

is_available

boolean

True if the email address is not yet registered and can be used for a new invitation.

success

boolean

Whether the API request was successful.

request_id

string

Unique identifier for request tracing and correlation.

Min length1

errors

Array of object (ApiError) | null

List of errors if the request failed.

object

Represents an error returned by the API.

code

string

Machine-readable error code (e.g. VALIDATION_ERROR, RESOURCE_NOT_FOUND).

Min length1

message

string

Human-readable error message.

Min length1

field

string | null

The request field that caused the error, if applicable.

details

string | null

Additional context about the error.

warnings

Array of object (ApiWarning) | null

List of non-fatal warnings from the request.

object

Represents a non-fatal warning from the API.

code

string

Machine-readable warning code.

Min length1

message

string

Human-readable warning message.

Min length1

401

Authentication token is missing or invalid.

Headers

WWW-Authenticate

string

Indicates the authentication scheme required. Returns `Bearer` with optional `error` and `error_description` parameters per RFC 6750.

Missing or invalid token

Authentication token is missing or invalid.

{
  "type": "https://developer.document360.com/errors/unauthorized",
  "title": "Unauthorized.",
  "status": 401,
  "detail": "The authentication token is missing or has expired.",
  "instance": null,
  "trace_id": "req_abc123def456",
  "errors": [
    {
      "code": "UNAUTHORIZED",
      "message": "Bearer token is missing or invalid.",
      "field": null,
      "details": null
    }
  ],
  "warnings": null
}

Expand All

object

RFC 7807 Problem Details response for V3 API errors. Content-Type: application/problem+json

type

string

URI reference identifying the error type (links to documentation).

Min length1

title

string

Short human-readable summary of the error type.

Min length1

status

integer (int32)

HTTP status code.

detail

string | null

Human-readable explanation specific to this occurrence.

instance

string | null

URI of the request that generated the error.

trace_id

string | null

Request trace identifier for correlation.

errors

Array of object (ApiError) | null

Structured list of specific errors (extension field).

object

Represents an error returned by the API.

code

string

Machine-readable error code (e.g. VALIDATION_ERROR, RESOURCE_NOT_FOUND).

Min length1

message

string

Human-readable error message.

Min length1

field

string | null

The request field that caused the error, if applicable.

details

string | null

Additional context about the error.

warnings

Array of object (ApiWarning) | null

Non-fatal warnings (extension field).

object

Represents a non-fatal warning from the API.

code

string

Machine-readable warning code.

Min length1

message

string

Human-readable warning message.

Min length1

429

Rate limit exceeded. Retry after the duration specified in the Retry-After header.

Headers

Retry-After

integer

Number of seconds to wait before retrying the request. Use exponential backoff with jitter for optimal retry behavior.

X-RateLimit-Limit

integer

The maximum number of requests allowed in the current time window. Limits are applied per API token per project.

X-RateLimit-Remaining

integer

The number of requests remaining in the current time window. When this reaches 0, subsequent requests will receive a 429 response.

X-RateLimit-Reset

integer

The UTC epoch timestamp (in seconds) when the current rate limit window resets.

Rate limit exceeded

Rate limit exceeded.

{
  "type": "https://developer.document360.com/errors/too-many-requests",
  "title": "Too Many Requests.",
  "status": 429,
  "detail": "Rate limit exceeded. Retry after the duration specified in the Retry-After header.",
  "instance": null,
  "trace_id": "req_abc123def456",
  "errors": [
    {
      "code": "TOO_MANY_REQUESTS",
      "message": "Rate limit exceeded. Retry after the duration specified in the Retry-After header.",
      "field": null,
      "details": null
    }
  ],
  "warnings": null
}

Expand All

object

RFC 7807 Problem Details response for V3 API errors. Content-Type: application/problem+json

type

string

URI reference identifying the error type (links to documentation).

Min length1

title

string

Short human-readable summary of the error type.

Min length1

status

integer (int32)

HTTP status code.

detail

string | null

Human-readable explanation specific to this occurrence.

instance

string | null

URI of the request that generated the error.

trace_id

string | null

Request trace identifier for correlation.

errors

Array of object (ApiError) | null

Structured list of specific errors (extension field).

object

Represents an error returned by the API.

code

string

Machine-readable error code (e.g. VALIDATION_ERROR, RESOURCE_NOT_FOUND).

Min length1

message

string

Human-readable error message.

Min length1

field

string | null

The request field that caused the error, if applicable.

details

string | null

Additional context about the error.

warnings

Array of object (ApiWarning) | null

Non-fatal warnings (extension field).

object

Represents a non-fatal warning from the API.

code

string

Machine-readable warning code.

Min length1

message

string

Human-readable warning message.

Min length1

500

An unexpected server error occurred.

Unexpected server error

Unexpected server error.

{
  "type": "https://developer.document360.com/errors/internal-error",
  "title": "Internal Server Error.",
  "status": 500,
  "detail": "An unexpected error occurred. Please try again or contact support.",
  "instance": null,
  "trace_id": "req_abc123def456",
  "errors": [
    {
      "code": "INTERNAL_SERVER_ERROR",
      "message": "An unexpected error occurred.",
      "field": null,
      "details": null
    }
  ],
  "warnings": null
}

Expand All

object

RFC 7807 Problem Details response for V3 API errors. Content-Type: application/problem+json

type

string

URI reference identifying the error type (links to documentation).

Min length1

title

string

Short human-readable summary of the error type.

Min length1

status

integer (int32)

HTTP status code.

detail

string | null

Human-readable explanation specific to this occurrence.

instance

string | null

URI of the request that generated the error.

trace_id

string | null

Request trace identifier for correlation.

errors

Array of object (ApiError) | null

Structured list of specific errors (extension field).

object

Represents an error returned by the API.

code

string

Machine-readable error code (e.g. VALIDATION_ERROR, RESOURCE_NOT_FOUND).

Min length1

message

string

Human-readable error message.

Min length1

field

string | null

The request field that caused the error, if applicable.

details

string | null

Additional context about the error.

warnings

Array of object (ApiWarning) | null

Non-fatal warnings (extension field).

object

Represents a non-fatal warning from the API.

code

string

Machine-readable warning code.

Min length1

message

string

Human-readable warning message.

Min length1

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