---
title: "Check a Page Before Logging In or Paying"
method: POST
path: "/api/precheck"
---

# Check a Page Before Logging In or Paying

`POST /api/precheck`

## Request

- Base URL: `https://dechonet.com`
- URL: `https://dechonet.com/api/precheck`
- Auth: one of:
  - none
  - HTTP bearer

Check the page an agent is about to log in, pay, download from or submit to: whether the address impersonates a brand, how new the domain is, whether DechoNet or a licensed feed has already flagged it, and — opened from Seoul (and Tokyo for Japan-targeted pages) as a phone — what the page turns into, including text it hides from people but an AI agent would read (instructions to ignore its rules, hand over secrets or keep the user out of it raise the answer to suspicious).

## Query parameters

- `lang` 'en' | 'ko'

## Request body

- object
  - `url` string, required: Address of the page (https://…)
  - `action` string, required: What is about to happen on the page
  - `expectedBrand` string, required: Brand the page is believed to belong to (e.g. 'PayPal', 'Shinhan Card'); a domain without that name is noted
  - `page` string, required: Optional page structure, host names only

## Response `200`

Result

- Envelope
  - `ok` boolean, required
  - `requestId` string, required
  - `cached` boolean, required: True when a recent stored result was returned.
  - `updatedAt` string, date-time, nullable: When the result was produced.
  - `data` unknown, required
  - `error` object, nullable, required
    - `code` 'INVALID_INPUT' | 'NOT_FOUND' | 'RATE_LIMITED' | 'UPSTREAM_ERROR' | 'UPSTREAM_TIMEOUT' | 'INVALID_API_KEY' | 'API_KEY_REQUIRED'
    - `message` string
    - `retryAfter` integer, nullable
    - `reason` string
  - `previousSnapshot` object: The previous stored result for the same target, when there is one.

## Other responses

- `400`: Invalid input
- `401`: Wrong or revoked API key, or a key is required
- `429`: Rate limited — see the Retry-After header
- `503`: An upstream source failed or timed out

---

[API](https://skmtc.dev/dechonet/apis/dechonet-api.md) · [All operations](https://skmtc.dev/dechonet/apis/dechonet-api/llms.txt) · [OpenAPI document](https://skmtc.dev/dechonet/apis/dechonet-api/revisions/87d89f1c4d1b?raw)