Didit Passive Liveness API

Overview

Verifies that a user is physically present by analyzing a single captured image — no explicit movement or interaction required.

Key constraints:

Supported formats: JPEG, PNG, WebP, TIFF
Maximum file size: 5MB
Image must contain exactly one clearly visible face
Original real-time photo only (no screenshots or printed photos)

Accuracy: 99.9% liveness detection accuracy, <0.1% false acceptance rate (FAR).

Capabilities: Liveness scoring, face quality assessment, luminance analysis, age/gender estimation, spoof detection (screen captures, printed copies, masks, deepfakes), duplicate face detection across sessions, blocklist matching.

Liveness methods: This standalone endpoint uses PASSIVE method (single-frame CNN). Workflow mode also supports ACTIVE_3D (action + flash, highest security) and FLASHING (3D flash, high security).

API Reference: https://docs.didit.me/standalone-apis/passive-liveness Feature Guide: https://docs.didit.me/core-technology/liveness/overview

Authentication

All requests require x-api-key header. Get your key from Didit Business Console → API & Webhooks, or via programmatic registration (see below).

Getting Started (No Account Yet?)

If you don't have a Didit API key, create one in 2 API calls:

Register: POST https://apx.didit.me/auth/v2/programmatic/register/ with {"email": "you@gmail.com", "password": "MyStr0ng!Pass"}
Check email for a 6-character OTP code
Verify: POST https://apx.didit.me/auth/v2/programmatic/verify-email/ with {"email": "you@gmail.com", "code": "A3K9F2"} → response includes api_key

To add credits: GET /v3/billing/balance/ to check, POST /v3/billing/top-up/ with {"amount_in_dollars": 50} for a Stripe checkout link.

See the didit-verification-management skill for full platform management (workflows, sessions, users, billing).

Endpoint

POST https://verification.didit.me/v3/passive-liveness/

Headers

Header	Value	Required
`x-api-key`	Your API key	Yes
`Content-Type`	`multipart/form-data`	Yes

Request Parameters (multipart/form-data)

Parameter	Type	Required	Default	Constraints	Description
`user_image`	file	Yes	—	JPEG/PNG/WebP/TIFF, max 5MB	User's face image
`face_liveness_score_decline_threshold`	integer	No	—	0-100	Scores below this = Declined
`rotate_image`	boolean	No	—	—	Try rotations to find upright face
`save_api_request`	boolean	No	`true`	—	Save in Business Console
`vendor_data`	string	No	—	—	Your identifier for session tracking

Example

import requests

response = requests.post(
    "https://verification.didit.me/v3/passive-liveness/",
    headers={"x-api-key": "YOUR_API_KEY"},
    files={"user_image": ("selfie.jpg", open("selfie.jpg", "rb"), "image/jpeg")},
    data={"face_liveness_score_decline_threshold": "80"},
)

const formData = new FormData();
formData.append("user_image", selfieFile);
formData.append("face_liveness_score_decline_threshold", "80");

const response = await fetch("https://verification.didit.me/v3/passive-liveness/", {
  method: "POST",
  headers: { "x-api-key": "YOUR_API_KEY" },
  body: formData,
});

Response (200 OK)

{
  "request_id": "a1b2c3d4-...",
  "liveness": {
    "status": "Approved",
    "method": "PASSIVE",
    "score": 95,
    "user_image": {
      "entities": [
        {"age": 22.16, "bbox": [156, 234, 679, 898], "confidence": 0.717, "gender": "male"}
      ],
      "best_angle": 0
    },
    "warnings": [],
    "face_quality": 85.0,
    "face_luminance": 50.0
  },
  "created_at": "2025-05-01T13:11:07.977806Z"
}

Status Values & Handling

Status	Meaning	Action
`"Approved"`	User is physically present	Proceed with your flow
`"Declined"`	Liveness check failed	Check `warnings`. May be a spoof or poor image quality

Error Responses

Code	Meaning	Action
`400`	Invalid request	Check file format, size, parameters
`401`	Invalid API key	Verify `x-api-key` header
`403`	Insufficient credits	Top up at business.didit.me

Response Field Reference

Field	Type	Description
`status`	string	`"Approved"` or `"Declined"`
`method`	string	Always `"PASSIVE"` for this endpoint
`score`	integer	0-100 liveness confidence (higher = more likely real). `null` if no face
`face_quality`	float	0-100 face image quality score. `null` if no face
`face_luminance`	float	Face luminance value. `null` if no face
`entities[].age`	float	Estimated age
`entities[].bbox`	array	Face bounding box `[x1, y1, x2, y2]`
`entities[].confidence`	float	Face detection confidence (0-1)
`entities[].gender`	string	`"male"` or `"female"`
`warnings`	array	`{risk, log_type, short_description, long_description}`

Warning Tags

Auto-Decline (always)

Tag	Description
`NO_FACE_DETECTED`	No face detected in image
`LIVENESS_FACE_ATTACK`	Potential spoofing attempt (printed photo, screen, mask)
`FACE_IN_BLOCKLIST`	Face matches a blocklisted entry
`POSSIBLE_FACE_IN_BLOCKLIST`	Possible blocklist match detected

Configurable (Decline / Review / Approve)

Tag	Description	Notes
`LOW_LIVENESS_SCORE`	Score below threshold	Configurable review + decline thresholds
`DUPLICATED_FACE`	Matches another approved session	—
`POSSIBLE_DUPLICATED_FACE`	May match another user	Configurable similarity threshold
`MULTIPLE_FACES_DETECTED`	Multiple faces (largest used for scoring)	Passive only
`LOW_FACE_QUALITY`	Image quality below threshold	Passive only
`LOW_FACE_LUMINANCE`	Image too dark	Passive only
`HIGH_FACE_LUMINANCE`	Image too bright/overexposed	Passive only

Common Workflows

Basic Liveness Check

1. Capture user selfie
2. POST /v3/passive-liveness/ → {"user_image": selfie}
3. If "Approved" → user is real, proceed
   If "Declined" → check warnings:
     - NO_FACE_DETECTED → ask user to retake with face clearly visible
     - LOW_FACE_QUALITY → ask for better lighting/positioning
     - LIVENESS_FACE_ATTACK → flag as potential fraud

Liveness + Face Match (combined)

1. POST /v3/passive-liveness/ → verify user is real
2. If Approved → POST /v3/face-match/ → compare selfie to ID photo
3. Both Approved → identity verified

Utility Scripts

export DIDIT_API_KEY="your_api_key"

python scripts/check_liveness.py selfie.jpg
python scripts/check_liveness.py selfie.jpg --threshold 80

didit-liveness-detection

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