Create an API Key for a User

Creates an API key owned by another member user. Requires the users scope on an unrestricted credential.

POST/users/{user_id}/api_keys

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.

AuthorizationBearer token (JWT) · headerrequired

Bearer token for an active signed-in UDX user.

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

Path parameters

user_idEntityIdrequired

The public identifier of one of the caller's member's users.

min length 1

Request body

requiredapplication/json

namestringrequired

A nickname for the new key.

min length 1 · max length 200

public_keystringrequired

PEM-encoded RSA public key.

min length 1 · max length 10000

scopesAPIKeyScope[]required

The permissions to grant this key.

min items 1 · max items 7

account_idstring | null

Restricts the key to a single account by its identifier. Omit (or null) to leave the key unrestricted.

Responses

201The created API key's metadata.

api_keyAPIKeyrequired

An API key's metadata.

Show properties

idEntityIdrequired

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

min length 1

namestringrequired

The nickname given to this key at creation.

max length 200

scopesAPIKeyScope[]required

The permissions this key was granted at creation.

max items 7

account_idstring | null

The identifier of the single account this key is restricted to or null if it's usable against every account accessible to the caller.

created_atstring<date-time>required

When this key was created.

max length 40

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 users:manage scope or is restricted to one account, a requested scope is not held by the user, or the user holds no grant on account_id.

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

404The user doesn't exist or is not one of the caller's member's users.

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

409This idempotency key is still in use, or its request completed with a response too large to replay. The problem type tells the two 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/users/6820943174116859281/api_keys" \
  -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": "desk trader bot",
  "public_key": "-----BEGIN PUBLIC KEY-----\nMIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAs73XRQ6kA8x4YhlozC6B\nF0+5iLfTU/MuYmvTCSaLH8/pgJBS+mggm5QeC0OkazwNMc1fzyx2n7OUFeN9Qm/M\nfyELPozTSSvPGebwUhsKyOZGKtO92HsejU075xnVsYWiYU+OA6DDxc5tR4mhMxS3\nDnHkwCQ1P2Z6SkaiYVQ2mMrGewT7TGlUYaZo+FI0svpJzMsJ5tNqjdh/9dsUC7WM\nATwMcoERX2Zb66ylk8dCw8rOoIE07/MTQfoH/z/++7rz+Jqt+KmnfKvSOOIr/WnE\nRLuBnd7OyKq7uCLGcWGq79FEa1ToWNcHAsLReElUU0shkqjRjaD1iKm83zh4XLWf\ngQIDAQAB\n-----END PUBLIC KEY-----",
  "scopes": [
    "read",
    "trade"
  ]
}'

Response

{
  "api_key": {
    "id": "3517456229634185646",
    "name": "desk trader bot",
    "scopes": [
      "read",
      "trade"
    ],
    "account_id": null,
    "created_at": "2026-06-01T12:00:00.000000Z"
  }
}

{
  "type": "urn:udx:problem:invalid-request-parameters",
  "title": "Bad Request",
  "status": 400,
  "detail": "invalid request parameters",
  "instance": "urn:request-id:8f14e45f-ceea-4abc-a743-e89a34d3f6ef"
}

{
  "type": "urn:udx:problem:unknown-version",
  "title": "Bad Request",
  "status": 400,
  "detail": "unknown UDX-Version \"1999-01-01\"; supported versions: 2026-07-15",
  "instance": "urn:request-id:8f14e45f-ceea-4abc-a743-e89a34d3f6ef"
}

{
  "type": "urn:udx:problem:invalid-authentication-credentials",
  "title": "Unauthorized",
  "status": 401,
  "detail": "invalid authentication credentials",
  "instance": "urn:request-id:8f14e45f-ceea-4abc-a743-e89a34d3f6ef"
}

{
  "type": "urn:udx:problem:insufficient-permissions",
  "title": "Forbidden",
  "status": 403,
  "detail": "insufficient permissions",
  "instance": "urn:request-id:8f14e45f-ceea-4abc-a743-e89a34d3f6ef"
}

{
  "type": "urn:udx:problem:scope-exceeds-user",
  "title": "Forbidden",
  "status": 403,
  "detail": "requested scope is not held by the key's user",
  "instance": "urn:request-id:8f14e45f-ceea-4abc-a743-e89a34d3f6ef"
}

{
  "type": "urn:udx:problem:request-with-header-in-progress",
  "title": "Conflict",
  "status": 409,
  "detail": "a request with this UDX-Idempotency-Key is already in progress",
  "instance": "urn:request-id:8f14e45f-ceea-4abc-a743-e89a34d3f6ef"
}

{
  "type": "urn:udx:problem:response-too-large-to-replay",
  "title": "Conflict",
  "status": 409,
  "detail": "this request already executed, but its response was too large to replay; do not resend it with a fresh UDX-Idempotency-Key, read the affected resource to confirm the result",
  "instance": "urn:request-id:8f14e45f-ceea-4abc-a743-e89a34d3f6ef"
}

{
  "type": "urn:udx:problem:header-used-for-different-request",
  "title": "Unprocessable Entity",
  "status": 422,
  "detail": "UDX-Idempotency-Key was already used for a different request",
  "instance": "urn:request-id:8f14e45f-ceea-4abc-a743-e89a34d3f6ef"
}

{
  "type": "urn:udx:problem:member-rate-limit-exceeded",
  "title": "Too Many Requests",
  "status": 429,
  "detail": "this member has temporarily exceeded its request rate",
  "instance": "urn:request-id:8f14e45f-ceea-4abc-a743-e89a34d3f6ef"
}

{
  "type": "urn:udx:problem:request-admission-unavailable",
  "title": "Service Unavailable",
  "status": 503,
  "detail": "request admission is temporarily unavailable",
  "instance": "urn:request-id:8f14e45f-ceea-4abc-a743-e89a34d3f6ef"
}