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Approve an assurance challenge

POST
/api/v1/me/challenges/{challenge_id}/approve
curl --request POST \
--url https://api.elephants.inc/api/v1/me/challenges/2489E9AD-2EE2-8E00-8EC9-32D5F69181C0/approve \
--header 'Authorization: Bearer <token>' \
--header 'Content-Type: application/json' \
--data '{ "credential": "example", "match_code": "example", "webauthn_response": { "challenge_id": "2489E9AD-2EE2-8E00-8EC9-32D5F69181C0", "id": "example", "raw_id": "example", "response": { "authenticator_data": "example", "client_data_json": "example", "signature": "example", "user_handle": "example" }, "type": "public-key" } }'

Approves a pending assurance challenge. Two credential shapes: the device’s approval credential (the app leg — the credential is rotated on every approval and the response carries the replacement), or a WebAuthn assertion minted via the challenge’s webauthn_options endpoint (the passkey leg — the response’s credential is null). When the challenge originated on any rail other than the app, the 3-digit match code shown on the originating surface is required — three wrong entries decline the challenge. The activated grant applies to the surface that minted the challenge.

challenge_id
required
string format: uuid

The challenge ID

Approval

Media typeapplication/json
One of:
ApproveChallengeWithAppCredential
object
credential
required

The device’s current approval credential (the app leg). Exactly one of credential and webauthn_response must be present.

string
>= 1 characters <= 1024 characters
match_code

The 3-digit code displayed on the originating surface. Required whenever the challenge’s origin_rail is not native_app; three wrong entries decline the challenge.

string
<= 255 characters /^[0-9]{3}$/
webauthn_response

WebAuthn assertion produced from options minted via the challenge’s webauthn_options endpoint — its challenge_id identifies the ceremony (the passkey leg). Exactly one of credential and webauthn_response must be present.

object
challenge_id
required
string format: uuid
id
required
string
<= 2048 characters
raw_id
required
string
<= 1048576 characters
response
required
object
authenticator_data
required
string
<= 1048576 characters
client_data_json
required
string
<= 1048576 characters
signature
required
string
<= 1048576 characters
user_handle
string | null
<= 1024 characters
type
required
string
Allowed values: public-key

Challenge approved; grant active

Media typeapplication/json
ChallengeApprovalResult
object
credential
required

App-credential approvals: the ROTATED approval credential — replace the stored one; the presented credential is spent. Null on webauthn approvals (a passkey rotates nothing).

string | null
expires_at
required

When the activated grant expires.

string format: date-time

Example generated

{
"credential": "example",
"expires_at": "2026-04-15T12:00:00Z"
}

Invalid request parameters or body

Media typeapplication/json
Error

Error response. error.type is the machine-readable code — branch on it, never on error.message or the HTTP status. error.message is display-grade prose safe to render to a user; when a failure has no specific copy it falls back to a generic sentence, so it never carries a machine code. Unrecognised failures collapse to the generic unprocessable_entity code, so treat type as an open enum: match the codes you handle and fall through to a default branch for the rest.

object
error
required
object
details

Structured error details (e.g. validation errors), when present

message
required

Display-grade message, safe to render verbatim. Never a machine code — do not branch on it.

string
request_id

Correlation ID for this request (also in the x-request-id response header). Include it when contacting support.

string
step_up
Any of:
StepUpChallenge
object
delivery
required

Method used to deliver this challenge

string
expires_at
required

Challenge expiry

string | null format: date-time
id
required

Sudo session ID returned to completeStepUp

string
match_code
required

3-digit number-matching code. This response is the ORIGINATING surface: display the code; a user approving from the Ele mobile app is asked to enter it. Null only for challenges minted before match codes existed.

string | null
methods
required

Available verification methods

Array<string>
step_up_authentication_id
required

The step-up authentication this challenge was minted from — a DIFFERENT id from id (the sudo session). completeStepUp takes id as sudo_session_id; requestStepUpFallback takes this one.

string format: uuid
webauthn
required
Any of:
PasskeyAuthenticationOptions
object
allow_credentials
required
Array<object>
object
id
required
string
transports
required
Array<string>
type
required
string
challenge
required
string
challenge_id
required
string format: uuid
rp_id
required
string
timeout
required
integer
user_verification
required
string
type
required

Machine-readable error code from a stable vocabulary (open enum — handle unknown values)

string

Example generated

{
"error": {
"details": "example",
"message": "example",
"request_id": "example",
"step_up": {
"delivery": "example",
"expires_at": "2026-04-15T12:00:00Z",
"id": "example",
"match_code": "example",
"methods": [
"example"
],
"step_up_authentication_id": "2489E9AD-2EE2-8E00-8EC9-32D5F69181C0",
"webauthn": {
"allow_credentials": [
{
"id": "example",
"transports": [
"example"
],
"type": "example"
}
],
"challenge": "example",
"challenge_id": "2489E9AD-2EE2-8E00-8EC9-32D5F69181C0",
"rp_id": "example",
"timeout": 1,
"user_verification": "example"
}
},
"type": "example"
}
}

Error response. error.type is the machine-readable code — branch on it, never on error.message or the HTTP status. error.message is display-grade prose safe to render to a user; when a failure has no specific copy it falls back to a generic sentence, so it never carries a machine code. Unrecognised failures collapse to the generic unprocessable_entity code, so treat type as an open enum: match the codes you handle and fall through to a default branch for the rest.

Media typeapplication/json
Error

Error response. error.type is the machine-readable code — branch on it, never on error.message or the HTTP status. error.message is display-grade prose safe to render to a user; when a failure has no specific copy it falls back to a generic sentence, so it never carries a machine code. Unrecognised failures collapse to the generic unprocessable_entity code, so treat type as an open enum: match the codes you handle and fall through to a default branch for the rest.

object
error
required
object
details

Structured error details (e.g. validation errors), when present

message
required

Display-grade message, safe to render verbatim. Never a machine code — do not branch on it.

string
request_id

Correlation ID for this request (also in the x-request-id response header). Include it when contacting support.

string
step_up
Any of:
StepUpChallenge
object
delivery
required

Method used to deliver this challenge

string
expires_at
required

Challenge expiry

string | null format: date-time
id
required

Sudo session ID returned to completeStepUp

string
match_code
required

3-digit number-matching code. This response is the ORIGINATING surface: display the code; a user approving from the Ele mobile app is asked to enter it. Null only for challenges minted before match codes existed.

string | null
methods
required

Available verification methods

Array<string>
step_up_authentication_id
required

The step-up authentication this challenge was minted from — a DIFFERENT id from id (the sudo session). completeStepUp takes id as sudo_session_id; requestStepUpFallback takes this one.

string format: uuid
webauthn
required
Any of:
PasskeyAuthenticationOptions
object
allow_credentials
required
Array<object>
object
id
required
string
transports
required
Array<string>
type
required
string
challenge
required
string
challenge_id
required
string format: uuid
rp_id
required
string
timeout
required
integer
user_verification
required
string
type
required

Machine-readable error code from a stable vocabulary (open enum — handle unknown values)

string

Example generated

{
"error": {
"details": "example",
"message": "example",
"request_id": "example",
"step_up": {
"delivery": "example",
"expires_at": "2026-04-15T12:00:00Z",
"id": "example",
"match_code": "example",
"methods": [
"example"
],
"step_up_authentication_id": "2489E9AD-2EE2-8E00-8EC9-32D5F69181C0",
"webauthn": {
"allow_credentials": [
{
"id": "example",
"transports": [
"example"
],
"type": "example"
}
],
"challenge": "example",
"challenge_id": "2489E9AD-2EE2-8E00-8EC9-32D5F69181C0",
"rp_id": "example",
"timeout": 1,
"user_verification": "example"
}
},
"type": "example"
}
}

Error response. error.type is the machine-readable code — branch on it, never on error.message or the HTTP status. error.message is display-grade prose safe to render to a user; when a failure has no specific copy it falls back to a generic sentence, so it never carries a machine code. Unrecognised failures collapse to the generic unprocessable_entity code, so treat type as an open enum: match the codes you handle and fall through to a default branch for the rest.

Media typeapplication/json
Error

Error response. error.type is the machine-readable code — branch on it, never on error.message or the HTTP status. error.message is display-grade prose safe to render to a user; when a failure has no specific copy it falls back to a generic sentence, so it never carries a machine code. Unrecognised failures collapse to the generic unprocessable_entity code, so treat type as an open enum: match the codes you handle and fall through to a default branch for the rest.

object
error
required
object
details

Structured error details (e.g. validation errors), when present

message
required

Display-grade message, safe to render verbatim. Never a machine code — do not branch on it.

string
request_id

Correlation ID for this request (also in the x-request-id response header). Include it when contacting support.

string
step_up
Any of:
StepUpChallenge
object
delivery
required

Method used to deliver this challenge

string
expires_at
required

Challenge expiry

string | null format: date-time
id
required

Sudo session ID returned to completeStepUp

string
match_code
required

3-digit number-matching code. This response is the ORIGINATING surface: display the code; a user approving from the Ele mobile app is asked to enter it. Null only for challenges minted before match codes existed.

string | null
methods
required

Available verification methods

Array<string>
step_up_authentication_id
required

The step-up authentication this challenge was minted from — a DIFFERENT id from id (the sudo session). completeStepUp takes id as sudo_session_id; requestStepUpFallback takes this one.

string format: uuid
webauthn
required
Any of:
PasskeyAuthenticationOptions
object
allow_credentials
required
Array<object>
object
id
required
string
transports
required
Array<string>
type
required
string
challenge
required
string
challenge_id
required
string format: uuid
rp_id
required
string
timeout
required
integer
user_verification
required
string
type
required

Machine-readable error code from a stable vocabulary (open enum — handle unknown values)

string

Example generated

{
"error": {
"details": "example",
"message": "example",
"request_id": "example",
"step_up": {
"delivery": "example",
"expires_at": "2026-04-15T12:00:00Z",
"id": "example",
"match_code": "example",
"methods": [
"example"
],
"step_up_authentication_id": "2489E9AD-2EE2-8E00-8EC9-32D5F69181C0",
"webauthn": {
"allow_credentials": [
{
"id": "example",
"transports": [
"example"
],
"type": "example"
}
],
"challenge": "example",
"challenge_id": "2489E9AD-2EE2-8E00-8EC9-32D5F69181C0",
"rp_id": "example",
"timeout": 1,
"user_verification": "example"
}
},
"type": "example"
}
}

Error response. error.type is the machine-readable code — branch on it, never on error.message or the HTTP status. error.message is display-grade prose safe to render to a user; when a failure has no specific copy it falls back to a generic sentence, so it never carries a machine code. Unrecognised failures collapse to the generic unprocessable_entity code, so treat type as an open enum: match the codes you handle and fall through to a default branch for the rest.

Media typeapplication/json
Error

Error response. error.type is the machine-readable code — branch on it, never on error.message or the HTTP status. error.message is display-grade prose safe to render to a user; when a failure has no specific copy it falls back to a generic sentence, so it never carries a machine code. Unrecognised failures collapse to the generic unprocessable_entity code, so treat type as an open enum: match the codes you handle and fall through to a default branch for the rest.

object
error
required
object
details

Structured error details (e.g. validation errors), when present

message
required

Display-grade message, safe to render verbatim. Never a machine code — do not branch on it.

string
request_id

Correlation ID for this request (also in the x-request-id response header). Include it when contacting support.

string
step_up
Any of:
StepUpChallenge
object
delivery
required

Method used to deliver this challenge

string
expires_at
required

Challenge expiry

string | null format: date-time
id
required

Sudo session ID returned to completeStepUp

string
match_code
required

3-digit number-matching code. This response is the ORIGINATING surface: display the code; a user approving from the Ele mobile app is asked to enter it. Null only for challenges minted before match codes existed.

string | null
methods
required

Available verification methods

Array<string>
step_up_authentication_id
required

The step-up authentication this challenge was minted from — a DIFFERENT id from id (the sudo session). completeStepUp takes id as sudo_session_id; requestStepUpFallback takes this one.

string format: uuid
webauthn
required
Any of:
PasskeyAuthenticationOptions
object
allow_credentials
required
Array<object>
object
id
required
string
transports
required
Array<string>
type
required
string
challenge
required
string
challenge_id
required
string format: uuid
rp_id
required
string
timeout
required
integer
user_verification
required
string
type
required

Machine-readable error code from a stable vocabulary (open enum — handle unknown values)

string

Example generated

{
"error": {
"details": "example",
"message": "example",
"request_id": "example",
"step_up": {
"delivery": "example",
"expires_at": "2026-04-15T12:00:00Z",
"id": "example",
"match_code": "example",
"methods": [
"example"
],
"step_up_authentication_id": "2489E9AD-2EE2-8E00-8EC9-32D5F69181C0",
"webauthn": {
"allow_credentials": [
{
"id": "example",
"transports": [
"example"
],
"type": "example"
}
],
"challenge": "example",
"challenge_id": "2489E9AD-2EE2-8E00-8EC9-32D5F69181C0",
"rp_id": "example",
"timeout": 1,
"user_verification": "example"
}
},
"type": "example"
}
}

Too many requests

Media typeapplication/json
RateLimitedError
object
error
required
object
details

Structured error details (e.g. validation errors), when present

message
required

Display-grade message, safe to render verbatim. Never a machine code — do not branch on it.

string
request_id

Correlation ID for this request (also in the x-request-id response header). Include it when contacting support.

string
step_up
Any of:
StepUpChallenge
object
delivery
required

Method used to deliver this challenge

string
expires_at
required

Challenge expiry

string | null format: date-time
id
required

Sudo session ID returned to completeStepUp

string
match_code
required

3-digit number-matching code. This response is the ORIGINATING surface: display the code; a user approving from the Ele mobile app is asked to enter it. Null only for challenges minted before match codes existed.

string | null
methods
required

Available verification methods

Array<string>
step_up_authentication_id
required

The step-up authentication this challenge was minted from — a DIFFERENT id from id (the sudo session). completeStepUp takes id as sudo_session_id; requestStepUpFallback takes this one.

string format: uuid
webauthn
required
Any of:
PasskeyAuthenticationOptions
object
allow_credentials
required
Array<object>
object
id
required
string
transports
required
Array<string>
type
required
string
challenge
required
string
challenge_id
required
string format: uuid
rp_id
required
string
timeout
required
integer
user_verification
required
string
type
required

Machine-readable error code from a stable vocabulary (open enum — handle unknown values)

string
error
required
object
type
required
string
Allowed value: rate_limited

Example

{
"error": {
"type": "rate_limited"
}
}
Retry-After
required
string

How long to wait before retrying, expressed as delay seconds or an HTTP date

Unexpected server error

Media typeapplication/json
Error

Error response. error.type is the machine-readable code — branch on it, never on error.message or the HTTP status. error.message is display-grade prose safe to render to a user; when a failure has no specific copy it falls back to a generic sentence, so it never carries a machine code. Unrecognised failures collapse to the generic unprocessable_entity code, so treat type as an open enum: match the codes you handle and fall through to a default branch for the rest.

object
error
required
object
details

Structured error details (e.g. validation errors), when present

message
required

Display-grade message, safe to render verbatim. Never a machine code — do not branch on it.

string
request_id

Correlation ID for this request (also in the x-request-id response header). Include it when contacting support.

string
step_up
Any of:
StepUpChallenge
object
delivery
required

Method used to deliver this challenge

string
expires_at
required

Challenge expiry

string | null format: date-time
id
required

Sudo session ID returned to completeStepUp

string
match_code
required

3-digit number-matching code. This response is the ORIGINATING surface: display the code; a user approving from the Ele mobile app is asked to enter it. Null only for challenges minted before match codes existed.

string | null
methods
required

Available verification methods

Array<string>
step_up_authentication_id
required

The step-up authentication this challenge was minted from — a DIFFERENT id from id (the sudo session). completeStepUp takes id as sudo_session_id; requestStepUpFallback takes this one.

string format: uuid
webauthn
required
Any of:
PasskeyAuthenticationOptions
object
allow_credentials
required
Array<object>
object
id
required
string
transports
required
Array<string>
type
required
string
challenge
required
string
challenge_id
required
string format: uuid
rp_id
required
string
timeout
required
integer
user_verification
required
string
type
required

Machine-readable error code from a stable vocabulary (open enum — handle unknown values)

string

Example generated

{
"error": {
"details": "example",
"message": "example",
"request_id": "example",
"step_up": {
"delivery": "example",
"expires_at": "2026-04-15T12:00:00Z",
"id": "example",
"match_code": "example",
"methods": [
"example"
],
"step_up_authentication_id": "2489E9AD-2EE2-8E00-8EC9-32D5F69181C0",
"webauthn": {
"allow_credentials": [
{
"id": "example",
"transports": [
"example"
],
"type": "example"
}
],
"challenge": "example",
"challenge_id": "2489E9AD-2EE2-8E00-8EC9-32D5F69181C0",
"rp_id": "example",
"timeout": 1,
"user_verification": "example"
}
},
"type": "example"
}
}