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UDX
2026-07-15

Create an Account

Creates an account for the caller’s member and starts its asynchronous setup. Requires an interactive user session or an unrestricted API key with the accounts scope; a key restricted to one account cannot create accounts.

POST/portfolio/accounts
Authorization
Authorization
UDX-Access-KeyAPI key · headerrequired

Opaque API key ID.

UDX-Access-TimestampAPI key · headerrequired

Unix time in milliseconds, within 30 seconds of server time.

UDX-Access-SignatureAPI key · headerrequired

Standard-base64 RSA-PSS/SHA-256 signature with a 32-byte salt.

or
AuthorizationBearer token (JWT) · headerrequired

Bearer token for an active signed-in UDX user.

Header parameters
Header parameters
UDX-Versionstring

Dated API version (YYYY-MM-DD).

min length 10 · max length 10
UDX-Idempotency-Keystring

Optional client-generated key that makes a mutation safe to retry.

min length 1 · max length 255
Request body
requiredapplication/json
namestringrequired

Human-readable name for the account.

min length 1 · max length 200
client_account_idstring

Your identifier for this account, unique among your member's accounts and fixed once the account is created. Use an opaque value rather than personal information.

min length 1 · max length 64
Responses
202The account was created and its asynchronous setup started.
accountAccountrequired

An account belonging to the caller's member.

Show properties
idEntityIdrequired

An exchange-assigned identifier. Treat it as an opaque, stable key with no internal structure.

min length 1
namestringrequired

Human-readable name for the account.

min length 1 · max length 200
statusstringrequired

Readiness of the account for this user.

Allowed:pendingactivefailed
reference_numberstring | null

Reference number for accounting.

client_account_idstring | nullrequired

The identifier you supplied when creating this account.

max length 64
400The request doesn't conform to this spec.
typestring<uri-reference>required

A stable URN identifying the kind of problem, for example urn:udx:problem:insufficient-permissions. Branch on it rather than on the localized detail. It is an identifier, not a URL to dereference.

max length 2048
titlestringrequired

A localized, human-readable summary of the error category. Stable for a given status code and resolved language — clients must not use it as a machine-readable discriminator.

max length 40
statusintegerrequired

The HTTP status code, repeated from the response itself.

detailstring

A localized, human-readable explanation specific to this occurrence. Clients must not parse it for machine-readable information.

max length 500
instancestring<uri-reference>

An identifier for this specific occurrence, so it can be correlated with server-side logs if you need to report it.

max length 100
401No valid credential was provided.
typestring<uri-reference>required

A stable URN identifying the kind of problem, for example urn:udx:problem:insufficient-permissions. Branch on it rather than on the localized detail. It is an identifier, not a URL to dereference.

max length 2048
titlestringrequired

A localized, human-readable summary of the error category. Stable for a given status code and resolved language — clients must not use it as a machine-readable discriminator.

max length 40
statusintegerrequired

The HTTP status code, repeated from the response itself.

detailstring

A localized, human-readable explanation specific to this occurrence. Clients must not parse it for machine-readable information.

max length 500
instancestring<uri-reference>

An identifier for this specific occurrence, so it can be correlated with server-side logs if you need to report it.

max length 100
403The credential lacks the accounts:manage scope or is restricted to one account.
typestring<uri-reference>required

A stable URN identifying the kind of problem, for example urn:udx:problem:insufficient-permissions. Branch on it rather than on the localized detail. It is an identifier, not a URL to dereference.

max length 2048
titlestringrequired

A localized, human-readable summary of the error category. Stable for a given status code and resolved language — clients must not use it as a machine-readable discriminator.

max length 40
statusintegerrequired

The HTTP status code, repeated from the response itself.

detailstring

A localized, human-readable explanation specific to this occurrence. Clients must not parse it for machine-readable information.

max length 500
instancestring<uri-reference>

An identifier for this specific occurrence, so it can be correlated with server-side logs if you need to report it.

max length 100
409Another of your member's accounts already has this client account ID, or this idempotency key is still in use or completed with a response too large to replay. The problem type tells them apart.
typestring<uri-reference>required

A stable URN identifying the kind of problem, for example urn:udx:problem:insufficient-permissions. Branch on it rather than on the localized detail. It is an identifier, not a URL to dereference.

max length 2048
titlestringrequired

A localized, human-readable summary of the error category. Stable for a given status code and resolved language — clients must not use it as a machine-readable discriminator.

max length 40
statusintegerrequired

The HTTP status code, repeated from the response itself.

detailstring

A localized, human-readable explanation specific to this occurrence. Clients must not parse it for machine-readable information.

max length 500
instancestring<uri-reference>

An identifier for this specific occurrence, so it can be correlated with server-side logs if you need to report it.

max length 100
422This idempotency key belongs to a different request.
typestring<uri-reference>required

A stable URN identifying the kind of problem, for example urn:udx:problem:insufficient-permissions. Branch on it rather than on the localized detail. It is an identifier, not a URL to dereference.

max length 2048
titlestringrequired

A localized, human-readable summary of the error category. Stable for a given status code and resolved language — clients must not use it as a machine-readable discriminator.

max length 40
statusintegerrequired

The HTTP status code, repeated from the response itself.

detailstring

A localized, human-readable explanation specific to this occurrence. Clients must not parse it for machine-readable information.

max length 500
instancestring<uri-reference>

An identifier for this specific occurrence, so it can be correlated with server-side logs if you need to report it.

max length 100
429The member rate limit was exceeded.
typestring<uri-reference>required

A stable URN identifying the kind of problem, for example urn:udx:problem:insufficient-permissions. Branch on it rather than on the localized detail. It is an identifier, not a URL to dereference.

max length 2048
titlestringrequired

A localized, human-readable summary of the error category. Stable for a given status code and resolved language — clients must not use it as a machine-readable discriminator.

max length 40
statusintegerrequired

The HTTP status code, repeated from the response itself.

detailstring

A localized, human-readable explanation specific to this occurrence. Clients must not parse it for machine-readable information.

max length 500
instancestring<uri-reference>

An identifier for this specific occurrence, so it can be correlated with server-side logs if you need to report it.

max length 100
500Something went wrong on UDX's side.
typestring<uri-reference>required

A stable URN identifying the kind of problem, for example urn:udx:problem:insufficient-permissions. Branch on it rather than on the localized detail. It is an identifier, not a URL to dereference.

max length 2048
titlestringrequired

A localized, human-readable summary of the error category. Stable for a given status code and resolved language — clients must not use it as a machine-readable discriminator.

max length 40
statusintegerrequired

The HTTP status code, repeated from the response itself.

detailstring

A localized, human-readable explanation specific to this occurrence. Clients must not parse it for machine-readable information.

max length 500
instancestring<uri-reference>

An identifier for this specific occurrence, so it can be correlated with server-side logs if you need to report it.

max length 100
503Request admission is unavailable.
typestring<uri-reference>required

A stable URN identifying the kind of problem, for example urn:udx:problem:insufficient-permissions. Branch on it rather than on the localized detail. It is an identifier, not a URL to dereference.

max length 2048
titlestringrequired

A localized, human-readable summary of the error category. Stable for a given status code and resolved language — clients must not use it as a machine-readable discriminator.

max length 40
statusintegerrequired

The HTTP status code, repeated from the response itself.

detailstring

A localized, human-readable explanation specific to this occurrence. Clients must not parse it for machine-readable information.

max length 500
instancestring<uri-reference>

An identifier for this specific occurrence, so it can be correlated with server-side logs if you need to report it.

max length 100
Request
curl -X POST "https://api.underdogexchange.com/portfolio/accounts" \
  -H "UDX-Access-Key: API_KEY_ID" \
  -H "UDX-Access-Timestamp: UNIX_MILLISECONDS" \
  -H "UDX-Access-Signature: BASE64_SIGNATURE" \
  -H "Content-Type: application/json" \
  -d '{
  "name": "customer 3f6b2a9e",
  "client_account_id": "customer-3f6b2a9e"
}'
Response
{
  "account": {
    "id": "9214170797177585522",
    "name": "customer 3f6b2a9e",
    "status": "pending",
    "reference_number": "UDX7051938824",
    "client_account_id": "customer-3f6b2a9e"
  }
}