Signature Matching

curl --request POST \
  --url https://{environment-subdomain}.idmetagroup.com/api/v3/verifications/signature-matching-passthrough \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "image1": "<BASE64_ENCODED_SIGNATURE_IMAGE_1>",
  "image2": "<BASE64_ENCODED_SIGNATURE_IMAGE_2>"
}
'

{
  "success": true,
  "message": "Signature Matching processed successfully",
  "data": {
    "similarity": 92.75,
    "verdict": "MATCH",
    "verdictDisplay": "Match"
  },
  "verificationStatus": "VERIFIED",
  "verificationStatusCode": 3,
  "transactionId": "7636df44-e539-4876-a4d5-408884229a92",
  "verificationType": "signature_matching",
  "createdAt": "2026-10-06 06:15:00+0000"
}

POST

api

verifications

signature-matching-passthrough

curl --request POST \
  --url https://{environment-subdomain}.idmetagroup.com/api/v3/verifications/signature-matching-passthrough \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "image1": "<BASE64_ENCODED_SIGNATURE_IMAGE_1>",
  "image2": "<BASE64_ENCODED_SIGNATURE_IMAGE_2>"
}
'

{
  "success": true,
  "message": "Signature Matching processed successfully",
  "data": {
    "similarity": 92.75,
    "verdict": "MATCH",
    "verdictDisplay": "Match"
  },
  "verificationStatus": "VERIFIED",
  "verificationStatusCode": 3,
  "transactionId": "7636df44-e539-4876-a4d5-408884229a92",
  "verificationType": "signature_matching",
  "createdAt": "2026-10-06 06:15:00+0000"
}

The response includes a similarity score, the match verdict, and the verification status for the two submitted signatures.

Request fields

`image1`

The first signature image. For example, the reference signature you hold on file for the customer. Required. Each image can be at most 2 MB after decoding.

`image2`

The second signature image to compare against image1. For example, a newly captured signature. Required. Accepts the same formats as image1.

`metadata`

Optional client-provided correlation data, such as your own reference ID. The API returns this object unchanged in the response.

Supported image formats

Base64 (JSON)
File upload (multipart)

Send application/json with each image as a Base64-encoded string. The data URI prefix is optional.

Format	Example value
Base64 string	`<BASE64_ENCODED_SIGNATURE_IMAGE_1>`
Data URI	`data:image/png;base64,<BASE64_ENCODED_SIGNATURE_IMAGE_1>`

{
  "image1": "<BASE64_ENCODED_SIGNATURE_IMAGE_1>",
  "image2": "<BASE64_ENCODED_SIGNATURE_IMAGE_2>"
}

Send multipart/form-data with each image as a file. Send each metadata key as its own form field.

Form field	Value
`image1`	First signature image file
`image2`	Second signature image file
`metadata[referenceId]`	Your reference ID (optional)

curl --request POST \
  --url "https://{environment-subdomain}.idmetagroup.com/api/v3/verifications/signature-matching-passthrough" \
  --header "Authorization: Bearer <API_TOKEN>" \
  --form "image1=@/path/to/signature-1.png" \
  --form "image2=@/path/to/signature-2.png" \
  --form "metadata[referenceId]=SIGNATURE-MATCH-0001"

Example request

This request compares a PNG signature with a JPEG signature sent as data URIs, and attaches a reference ID and source for correlation.

{
  "image1": "data:image/png;base64,<BASE64_ENCODED_SIGNATURE_IMAGE_1>",
  "image2": "data:image/jpeg;base64,<BASE64_ENCODED_SIGNATURE_IMAGE_2>"
}

Interpret the response

success: true means the API completed the comparison. Use verificationStatus and data.verdict to determine the outcome.

Field	Meaning
`data.similarity`	Similarity score between the two signatures. Higher values indicate a closer match.
`data.verdict`	Match verdict: `MATCH`, `INCONCLUSIVE`, or `NO MATCH`.
`data.verdictDisplay`	Human-readable form of the verdict: `Match`, `Inconclusive`, or `No Match`.
`verificationStatus`	Verification outcome derived from the verdict.
`transactionId`	Identifier for this comparison. `null` when the request fails validation.
`metadata`	The `metadata` object you sent, returned unchanged.

The verdict maps to the verification status as follows:

`data.verdict`	`verificationStatus`	Code	HTTP	Billable
`MATCH`	`VERIFIED`	`3`	`200`	Yes
`NO MATCH`	`REJECTED`	`1`	`200`	Yes
`INCONCLUSIVE`	`REVIEW_NEEDED`	`2`	`200`	Yes
No valid result	`FAILED`	`6`	`400`	No
Provider failure	`FAILED`	`6`	`502`	No

REJECTED and REVIEW_NEEDED are completed comparisons, not API failures. FAILED means the comparison could not be completed, either because no signature was found in one of the images (HTTP 400) or because the verification provider is unavailable (HTTP 502). A request missing image1 or image2 also returns HTTP 400, before a transaction is created.

Authorizations

Authorization

string

header

required

Use your API token as a Bearer token in the Authorization header.

Headers

Authorization

string

required

Example:

"Bearer {your_api_token}"

string

default:application/json

Content-Type

string

default:application/json

Body

image1

string

required

First signature image. In JSON, a Base64-encoded image with or without a data URI prefix (for example data:image/png;base64,...). In multipart/form-data, an image file. Maximum 2 MB after decoding. URLs are not accepted.

image2

string

required

Second signature image to compare against image1, in the same accepted formats. Maximum 2 MB after decoding. URLs are not accepted.

metadata

object

Optional client-provided correlation data, echoed back on the response.

Example:

{ "referenceId": "SIGNATURE-MATCH-0001" }

Response

Comparison completed. Verified, review-needed, and rejected outcomes all use HTTP 200 and are billed.

success

boolean

required

Example:

true

message

string

required

Example:

"Signature Matching processed successfully"

data

object

required

Show child attributes

verificationStatus

enum<string>

required

Available options:

VERIFIED,

REVIEW_NEEDED,

REJECTED

verificationStatusCode

enum<integer>

required

3 = Verified, 2 = Review Needed, 1 = Rejected.

Available options:

3,

2,

1

transactionId

string<uuid>

required

verificationType

string

required

Example:

"signature_matching"

createdAt

string

required

Example:

"2026-10-06 06:15:00+0000"

metadata

object | null

API documentation

Compliances

Australia DVS

Philippines Government

Indonesia Government

Document OCR

Request fields

`image1`

`image2`

`metadata`

Supported image formats

Example request

Interpret the response

Authorizations

Headers

Body

Response

​Request fields

​image1

​image2

​metadata

​Supported image formats

​Example request

​Interpret the response

Authorizations

Headers

Body

Response

Request fields

`image1`

`image2`

`metadata`

Supported image formats

Example request

Interpret the response