---
title: "Look up whether a user is known to Trustly"
method: GET
path: "/customers/lookup"
tags: ["networkCheckApi"]
---

# Look up whether a user is known to Trustly

`GET /customers/lookup`

## Request

- Base URL: `https://sandbox.trustly.one/api/v1`
- URL: `https://sandbox.trustly.one/api/v1/customers/lookup`
- Auth: HTTP basic

Checks whether a user has previously used Trustly, based on one or more provided identifiers (email or phone).

Merchants can use this endpoint without having to launch Trustly widget/lightbox. One such use case could be to use this endpoint early in the payment funnel — before the user reaches the payment selection screen — to determine whether to surface Trustly as the top payment option. A `true` response indicates the user is already familiar with Pay by Bank and is more likely to complete a Trustly-powered transaction.

**How it works:** The lookup queries Trustly's user database across all stored identifiers. If any provided identifier matches a known Trustly user, `isInTrustlyNetwork` is returned as `true`.

**Authentication:** Requests must be authenticated with HTTP Basic Auth using your `accessId` as the username and `accessKey` as the password.

## Query parameters

- `email` string, email, required
- `phone` string

## Response `200`

Lookup result

- CustomerLookupResponse
  - `isInTrustlyNetwork` boolean: True if a transaction has ever been made with any of the provided identifiers.
  - `errorsList` CustomerLookupResponseErrorsListItems[]: Present only on error responses.
    - `code` integer
    - `message` string
    - `location` string
    - `domain` string
    - `occurredAt` integer

## Other responses

- `400`: Bad Request — missing mandatory fields or invalid email
- `401`: Access not authorized
- `500`: Internal server error

## Changes

- **2026-09-17** `dd0a38d95088`: 1 warning, 1 info
  - deleted the `header` request parameter `Authorization`
  - the endpoint scheme security `HTTPBasic` was added to the API
- **2026-09-12** `1d5aabcc1d16`: 1 info
  - api operation id `get-customer-lookup` removed and replaced with `networkCheckApi_get-customer-lookup`

[Operation history](https://skmtc.dev/trustly/apis/trustly-scalar-api/changes/customers/lookup/get.md)

---

[API](https://skmtc.dev/trustly/apis/trustly-scalar-api.md) - [All operations](https://skmtc.dev/trustly/apis/trustly-scalar-api/llms.txt) - [OpenAPI document](https://skmtc.dev/trustly/apis/trustly-scalar-api/revisions/5c376a06c899?raw)