> ## Documentation Index
> Fetch the complete documentation index at: https://docs.truthlocks.com/llms.txt
> Use this file to discover all available pages before exploring further.
# Evaluate ATO risk
> Evaluate a login event against account takeover heuristics. Tracks failed login velocity per subject and triggers alerts when thresholds are exceeded.
Evaluates a login event against the ATO heuristic engine. The platform tracks failed logins per subject in a rolling one-hour window and derives a risk level from the current count. When a threshold is crossed, an alert is created and a risk signal is automatically ingested into the [risk signal pipeline](/guides/risk-signals).
See the [account takeover detection guide](/guides/ato-detection) for the full workflow, threshold reference, and integration patterns.
## Threshold rules
| Failed logins (1 h window) | Risk level | Auto-alert |
| :------------------------- | :--------- | :-------------------------- |
| 0–4 | normal | No |
| 5–9 | elevated | Yes — `velocity_exceeded` |
| 10–19 | high | Yes — `velocity_exceeded` |
| 20+ | critical | Yes — `credential_stuffing` |
## Request
User identifier (user ID, email, or external ID).
Login event type: `login.failed`, `login.failed.repeated`, `login.success`, `login.new_device`
Type of subject. Defaults to `user`.
Source IP address for the login attempt.
## Response
The subject that was evaluated.
Type of subject (`user`).
Current ATO risk level: `normal` | `elevated` | `high` | `critical`
Numeric risk score: 10 (normal), 50 (elevated), 70 (high), 90 (critical).
Number of failed logins in the current one-hour window.
`true` if a new alert was triggered by this evaluation.
Alert category when triggered: `velocity_exceeded` or `credential_stuffing`.
UUID of the auto-ingested risk signal (only present when an alert fired).
The event type that was evaluated.
## OpenAPI
````yaml mint-openapi.yaml POST /v1/risk/ato/evaluate
openapi: 3.0.3
info:
title: Truthlocks API
description: >
Truthlocks is a universal verification infrastructure for documents,
credentials, and digital assets.
This specification defines the canonical API for interacting with Truthlocks
services.
## Base URLs
- **Production**: `https://api.truthlocks.com`
- **Sandbox**: `https://sandbox-api.truthlocks.com`
## Authentication
- **API Keys**: Use `X-API-Key` header for machine-to-machine operations
- **Bearer Tokens**: Use `Authorization: Bearer ` for user-initiated
operations
## Tenant Identity
In production, tenant identity is derived from the authenticated context
(API key or JWT).
The `X-Tenant-ID` header is ignored in production to prevent spoofing.
version: 1.0.0
contact:
name: Truthlocks Support
url: https://truthlocks.com/support
email: support@truthlocks.com
servers:
- url: https://api.truthlocks.com
description: Production API
- url: https://sandbox-api.truthlocks.com
description: Sandbox Environment
security:
- APIKey: []
tags:
- name: Authentication
description: API key and token management
- name: Issuers
description: Issuer registration and trust management
- name: Keys
description: Cryptographic key management for issuers
- name: Attestations
description: Attestation lifecycle (mint, revoke, supersede)
- name: Verification
description: Attestation verification and proof bundles
- name: Governance
description: Issuer governance workflows (admin only)
- name: Identity
description: Organization, user, and role management
- name: Audit
description: Audit event queries
- name: Platform
description: Platform administration (super admin only)
- name: Platform Review
description: Staff review workflows for issuer applications
- name: Tenant Console
description: Tenant profile and lifecycle endpoints
- name: Health
description: Service health and readiness endpoints
- name: Risk
description: Risk signal ingestion and fraud detection
- name: Risk Enforcement
description: Risk enforcement actions — block, challenge, quarantine, and configuration
- name: Billing
description: Billing, subscription, and addon management
- name: Machine Identity
description: >-
Machine Agent Identity Protocol (MAIP) — agent registration, sessions,
trust, witness, compliance, orchestration, and observability
externalDocs:
description: Transparency read-only API (separate service spec)
url: >-
https://github.com/truthlocks/truthlock/blob/main/docs/transparency/openapi.yaml
paths:
/v1/risk/ato/evaluate:
post:
tags:
- Risk
summary: ATO risk evaluate
description: >-
Evaluates account takeover risk for a subject using behavioral signals
and device fingerprints.
operationId: risk.ato.evaluate
requestBody:
required: true
content:
application/json:
schema:
type: object
required:
- subject_id
properties:
subject_id:
type: string
ip_address:
type: string
user_agent:
type: string
device_fingerprint:
type: string
action:
type: string
responses:
'200':
description: ATO evaluation result
content:
application/json:
schema:
type: object
properties:
risk_score:
type: integer
decision:
type: string
signals:
type: array
items:
type: object
'401':
description: Authentication required
content:
application/json:
schema:
$ref: '#/components/schemas/ErrorEnvelope'
security:
- APIKey: []
components:
schemas:
ErrorEnvelope:
type: object
required:
- code
- message
- http_status
properties:
code:
type: string
description: Machine-readable error code
enum:
- AUTH_REQUIRED
- AUTH_INVALID
- PERMISSION_DENIED
- TENANT_IDENTITY_UNVERIFIED
- NOT_FOUND
- VALIDATION_ERROR
- CONFLICT
- PAYLOAD_TOO_LARGE
- RATE_LIMIT_EXCEEDED
- QUOTA_EXCEEDED
- SERVICE_UNAVAILABLE
- INTERNAL_ERROR
message:
type: string
description: Human-readable error message
http_status:
type: integer
description: HTTP status code
retry_after_ms:
type: integer
description: Milliseconds to wait before retrying (for rate limits)
details:
type: object
description: Additional error context
example:
code: AUTH_REQUIRED
message: Authentication required
http_status: 401
securitySchemes:
APIKey:
type: apiKey
in: header
name: X-API-Key
description: API key for machine-to-machine authentication
````