POST Request a one-time Ed25519 machine challenge
/api/v1/auth/machine/challenge
Requires the enabled registration/recovery capability for the requested purpose. Save the private Ed25519 recovery identity and proposed management credential locally before the request. The challenge binds purpose and public key and expires in five minutes.
On this page
Access and permissions
Requires the enabled registration/recovery capability for the requested purpose. Save the private Ed25519 recovery identity and proposed management credential locally before the request. The challenge binds purpose and public key and expires in five minutes.
No account sign-in is required. Any listed browser-origin checks and rate limits still apply.
Parameters and headers
No path, query or additional request-header parameters.
Request body
| Field | Type and limits | Required | Meaning |
|---|---|---|---|
| $ | object; {"additionalProperties":false} | Yes | — |
| $.public_key | string; {"maxLength":43,"minLength":43,"pattern":"^[A-Za-z0-9_-]{42}[AEIMQUYcgkosw048]$"} | Yes | Ed25519 public key: exactly 32 bytes, canonical unpadded base64url. |
| $.purpose | string; {"enum":["register","recover"]} | Yes | — |
Responses
| Header | Type and limits | Meaning |
|---|---|---|
| Cache-Control | string; {"pattern":"(?:^|,\\s*)no-store(?:,|$)"} | Private API responses prohibit storage. Public OAuth metadata is cached for 300 seconds; live streams additionally prohibit transformation. |
| Content-Language | string; {"enum":["en","de"]} | Language of human-readable response text, resolved from Accept-Language or the documented browser preference. Technical codes and identifiers remain stable. |
| Referrer-Policy | JSON; {"enum":["strict-origin-when-cross-origin","no-referrer"]} | The default referrer policy is strict-origin-when-cross-origin. Provider-login responses use no-referrer to protect login parameters. |
| Vary | string | Responses vary by Accept-Language; browser-rendered responses can also vary by the preference cookie. |
| X-Content-Type-Options | JSON; {"const":"nosniff"} | The browser must use the declared content type. |
| X-Frame-Options | JSON; {"const":"DENY"} | The response must not be embedded in a frame. |
| X-Request-ID | string | Server-generated request identifier. Include this when reporting an error; inbound values are not trusted. |
application/json
| Field | Type and limits | Required | Meaning |
|---|---|---|---|
| $ | object | Yes | — |
| $.challenge_id | string | Yes | UUID of the challenge issued to this browser or machine request. |
| $.expires_at | string; {"format":"date-time"} | Yes | Expiry timestamp. A successful request does not extend this deadline unless explicitly documented. |
| $.nonce | string | Yes | — |
| $.privacy_version | string | Yes | SHA-256 version returned for the currently published privacy text. |
| $.purpose | string | Yes | — |
| $.terms_version | string | Yes | SHA-256 version returned for the currently published terms. Retrieve the current text before accepting. |
{
"challenge_id": "demo",
"expires_at": "2026-09-30T12:00:00Z",
"nonce": "demo",
"privacy_version": "demo",
"purpose": "demo",
"terms_version": "demo"
}| Stable error codes |
|---|
| invalid_peer |
| Header | Type and limits | Meaning |
|---|---|---|
| Cache-Control | string; {"pattern":"(?:^|,\\s*)no-store(?:,|$)"} | Private API responses prohibit storage. Public OAuth metadata is cached for 300 seconds; live streams additionally prohibit transformation. |
| Content-Language | string; {"enum":["en","de"]} | Language of human-readable response text, resolved from Accept-Language or the documented browser preference. Technical codes and identifiers remain stable. |
| Referrer-Policy | JSON; {"enum":["strict-origin-when-cross-origin","no-referrer"]} | The default referrer policy is strict-origin-when-cross-origin. Provider-login responses use no-referrer to protect login parameters. |
| Vary | string | Responses vary by Accept-Language; browser-rendered responses can also vary by the preference cookie. |
| X-Content-Type-Options | JSON; {"const":"nosniff"} | The browser must use the declared content type. |
| X-Frame-Options | JSON; {"const":"DENY"} | The response must not be embedded in a frame. |
| X-Request-ID | string | Server-generated request identifier. Include this when reporting an error; inbound values are not trusted. |
application/problem+json
| Field | Type and limits | Required | Meaning |
|---|---|---|---|
| $ | Problem | Yes | — |
| $.code | string | Yes | Stable machine-readable error code |
| $.detail | string | Yes | Short localized explanation without internal error details |
| $.instance | string | Yes | Unique relative identifier /api/v1/requests/{request_id}; not a retrievable resource |
| $.message | string | Yes | Temporarily identical to detail for existing clients |
| $.message_key | string | Yes | Stable translation key for changing the displayed language without another request |
| $.message_params | object; {"additionalProperties":true} | Yes | Named, safely rendered message parameters; never arbitrary HTML |
| $.request_id | string; {"pattern":"^[0-9a-f]{32}$"} | Yes | Server-generated diagnostic identifier. It contains no login token or credential. |
| $.status | integer; {"maximum":599,"minimum":400} | Yes | — |
| $.title | string | Yes | Localized HTTP status title |
| $.type | string; {"const":"about:blank"} | Yes | — |
{
"code": "demo",
"detail": "Demo error detail; inspect the documented code.",
"instance": "demo",
"message": "Demo error detail; inspect the documented code.",
"message_key": "errors.requestFailed",
"message_params": {},
"request_id": "00000000000000000000000000000000",
"status": 400,
"title": "Demo error",
"type": "about:blank"
}| Stable error codes |
|---|
| invalid_input |
| Header | Type and limits | Meaning |
|---|---|---|
| Cache-Control | string; {"pattern":"(?:^|,\\s*)no-store(?:,|$)"} | Private API responses prohibit storage. Public OAuth metadata is cached for 300 seconds; live streams additionally prohibit transformation. |
| Content-Language | string; {"enum":["en","de"]} | Language of human-readable response text, resolved from Accept-Language or the documented browser preference. Technical codes and identifiers remain stable. |
| Referrer-Policy | JSON; {"enum":["strict-origin-when-cross-origin","no-referrer"]} | The default referrer policy is strict-origin-when-cross-origin. Provider-login responses use no-referrer to protect login parameters. |
| Vary | string | Responses vary by Accept-Language; browser-rendered responses can also vary by the preference cookie. |
| X-Content-Type-Options | JSON; {"const":"nosniff"} | The browser must use the declared content type. |
| X-Frame-Options | JSON; {"const":"DENY"} | The response must not be embedded in a frame. |
| X-Request-ID | string | Server-generated request identifier. Include this when reporting an error; inbound values are not trusted. |
application/problem+json
| Field | Type and limits | Required | Meaning |
|---|---|---|---|
| $ | Problem | Yes | — |
| $.code | string | Yes | Stable machine-readable error code |
| $.detail | string | Yes | Short localized explanation without internal error details |
| $.instance | string | Yes | Unique relative identifier /api/v1/requests/{request_id}; not a retrievable resource |
| $.message | string | Yes | Temporarily identical to detail for existing clients |
| $.message_key | string | Yes | Stable translation key for changing the displayed language without another request |
| $.message_params | object; {"additionalProperties":true} | Yes | Named, safely rendered message parameters; never arbitrary HTML |
| $.request_id | string; {"pattern":"^[0-9a-f]{32}$"} | Yes | Server-generated diagnostic identifier. It contains no login token or credential. |
| $.status | integer; {"maximum":599,"minimum":400} | Yes | — |
| $.title | string | Yes | Localized HTTP status title |
| $.type | string; {"const":"about:blank"} | Yes | — |
{
"code": "demo",
"detail": "Demo error detail; inspect the documented code.",
"instance": "demo",
"message": "Demo error detail; inspect the documented code.",
"message_key": "errors.requestFailed",
"message_params": {},
"request_id": "00000000000000000000000000000000",
"status": 422,
"title": "Demo error",
"type": "about:blank"
}| Stable error codes |
|---|
| challenge_capacity |
| challenge_rate |
| Header | Type and limits | Meaning |
|---|---|---|
| Cache-Control | string; {"pattern":"(?:^|,\\s*)no-store(?:,|$)"} | Private API responses prohibit storage. Public OAuth metadata is cached for 300 seconds; live streams additionally prohibit transformation. |
| Content-Language | string; {"enum":["en","de"]} | Language of human-readable response text, resolved from Accept-Language or the documented browser preference. Technical codes and identifiers remain stable. |
| Referrer-Policy | JSON; {"enum":["strict-origin-when-cross-origin","no-referrer"]} | The default referrer policy is strict-origin-when-cross-origin. Provider-login responses use no-referrer to protect login parameters. |
| Retry-After | string; {"pattern":"^[0-9]+$"} | Seconds before retry. Preserve supported idempotency identifiers and respect the operation’s mutation semantics. |
| Vary | string | Responses vary by Accept-Language; browser-rendered responses can also vary by the preference cookie. |
| X-Content-Type-Options | JSON; {"const":"nosniff"} | The browser must use the declared content type. |
| X-Frame-Options | JSON; {"const":"DENY"} | The response must not be embedded in a frame. |
| X-Request-ID | string | Server-generated request identifier. Include this when reporting an error; inbound values are not trusted. |
application/problem+json
| Field | Type and limits | Required | Meaning |
|---|---|---|---|
| $ | Problem | Yes | — |
| $.code | string | Yes | Stable machine-readable error code |
| $.detail | string | Yes | Short localized explanation without internal error details |
| $.instance | string | Yes | Unique relative identifier /api/v1/requests/{request_id}; not a retrievable resource |
| $.message | string | Yes | Temporarily identical to detail for existing clients |
| $.message_key | string | Yes | Stable translation key for changing the displayed language without another request |
| $.message_params | object; {"additionalProperties":true} | Yes | Named, safely rendered message parameters; never arbitrary HTML |
| $.request_id | string; {"pattern":"^[0-9a-f]{32}$"} | Yes | Server-generated diagnostic identifier. It contains no login token or credential. |
| $.status | integer; {"maximum":599,"minimum":400} | Yes | — |
| $.title | string | Yes | Localized HTTP status title |
| $.type | string; {"const":"about:blank"} | Yes | — |
{
"code": "demo",
"detail": "Demo error detail; inspect the documented code.",
"instance": "demo",
"message": "Demo error detail; inspect the documented code.",
"message_key": "errors.requestFailed",
"message_params": {},
"request_id": "00000000000000000000000000000000",
"status": 429,
"title": "Demo error",
"type": "about:blank"
}| Stable error codes |
|---|
| machine_registration_unavailable |
| unavailable |
| Header | Type and limits | Meaning |
|---|---|---|
| Cache-Control | string; {"pattern":"(?:^|,\\s*)no-store(?:,|$)"} | Private API responses prohibit storage. Public OAuth metadata is cached for 300 seconds; live streams additionally prohibit transformation. |
| Content-Language | string; {"enum":["en","de"]} | Language of human-readable response text, resolved from Accept-Language or the documented browser preference. Technical codes and identifiers remain stable. |
| Referrer-Policy | JSON; {"enum":["strict-origin-when-cross-origin","no-referrer"]} | The default referrer policy is strict-origin-when-cross-origin. Provider-login responses use no-referrer to protect login parameters. |
| Retry-After | string; {"pattern":"^[0-9]+$"} | Seconds before retry. Preserve supported idempotency identifiers and respect the operation’s mutation semantics. |
| Vary | string | Responses vary by Accept-Language; browser-rendered responses can also vary by the preference cookie. |
| X-Content-Type-Options | JSON; {"const":"nosniff"} | The browser must use the declared content type. |
| X-Frame-Options | JSON; {"const":"DENY"} | The response must not be embedded in a frame. |
| X-Request-ID | string | Server-generated request identifier. Include this when reporting an error; inbound values are not trusted. |
application/problem+json
| Field | Type and limits | Required | Meaning |
|---|---|---|---|
| $ | Problem | Yes | — |
| $.code | string | Yes | Stable machine-readable error code |
| $.detail | string | Yes | Short localized explanation without internal error details |
| $.instance | string | Yes | Unique relative identifier /api/v1/requests/{request_id}; not a retrievable resource |
| $.message | string | Yes | Temporarily identical to detail for existing clients |
| $.message_key | string | Yes | Stable translation key for changing the displayed language without another request |
| $.message_params | object; {"additionalProperties":true} | Yes | Named, safely rendered message parameters; never arbitrary HTML |
| $.request_id | string; {"pattern":"^[0-9a-f]{32}$"} | Yes | Server-generated diagnostic identifier. It contains no login token or credential. |
| $.status | integer; {"maximum":599,"minimum":400} | Yes | — |
| $.title | string | Yes | Localized HTTP status title |
| $.type | string; {"const":"about:blank"} | Yes | — |
{
"code": "demo",
"detail": "Demo error detail; inspect the documented code.",
"instance": "demo",
"message": "Demo error detail; inspect the documented code.",
"message_key": "errors.requestFailed",
"message_params": {},
"request_id": "00000000000000000000000000000000",
"status": 503,
"title": "Demo error",
"type": "about:blank"
}Retries and asynchronous work
This change does not have a general retry guarantee. If the response is unclear, read the affected resource before trying again. Follow Retry-After waiting times and request new sign-in or action codes when they expire.
Request examples
Replace demo IDs, timestamps and placeholders with your own values. For a retry, keep the same IDs, time and content. These examples do not run requests on this page.
Keep login links, codes, cookies and keys private. Do not print them in logs or share them in support requests.
curl --silent --show-error --output /dev/null --write-out "%{http_code}\n" \
--request POST \
--header "Content-Type: application/json" \
--data-binary '{"public_key":"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA","purpose":"register"}' \
"https://metribeacon.com/api/v1/auth/machine/challenge"
import json
from pathlib import Path
from urllib.request import Request, HTTPRedirectHandler, build_opener
from urllib.error import HTTPError
headers = {}
headers["Content-Type"] = "application/json"
request = Request("https://metribeacon.com/api/v1/auth/machine/challenge", data="{\"public_key\":\"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA\",\"purpose\":\"register\"}".encode("utf-8"), headers=headers, method="POST")
class NoRedirect(HTTPRedirectHandler):
def redirect_request(self, request, fp, code, message, headers, target):
return None
opener = build_opener(NoRedirect())
try:
with opener.open(request, timeout=10) as response:
print(response.status)
except HTTPError as error:
print(error.code)
error.close()
import { readFile } from "node:fs/promises";
import { homedir } from "node:os";
import { join } from "node:path";
const headers = {};
headers["Content-Type"] = "application/json";
const response = await fetch("https://metribeacon.com/api/v1/auth/machine/challenge", {
method: "POST", headers, redirect: "manual",
signal: AbortSignal.timeout(10000), body: "{\"public_key\":\"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA\",\"purpose\":\"register\"}",
});
console.log(response.status);
await response.body?.cancel();
package main
import (
"fmt"
"net/http"
"time"
"strings"
)
func main() {
request, err := http.NewRequest("POST", "https://metribeacon.com/api/v1/auth/machine/challenge", strings.NewReader("{\"public_key\":\"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA\",\"purpose\":\"register\"}"))
if err != nil { panic("request failed; credentials and response omitted") }
request.Header.Set("Content-Type", "application/json")
client := &http.Client{Timeout: 10*time.Second, CheckRedirect: func(*http.Request, []*http.Request) error { return http.ErrUseLastResponse }}
response, err := client.Do(request)
if err != nil { panic("request failed; credentials and response omitted") }
defer response.Body.Close()
fmt.Println(response.StatusCode)
}
Related guides
- HTTP API, OAuth and MCP
Find the user API endpoints, their permissions, fields, examples and response formats.
- POST Request email verification for a machine account
Requires account:write on a machine credential. The existing verified address and tier remain until confirmation. Replies are generic for addresses already in use.
- POST Replace a machine management credential using recovery
Sign a fresh recover challenge with the existing recovery identity. Persist the replacement credential before requesting recovery. Repeating with a fresh challenge yields the same account and returns no secret.
- POST Register or retrieve a machine account
The version-2 Ed25519 signature binds the challenge and both legal-document versions and acknowledgements. Only a SHA-256 credential hash is stored. A retry needs a fresh challenge and the same locally persisted credential.