---
title: "Look up a single photo by fingerprint"
method: GET
path: "/v2/lookup"
tags: ["Registry"]
---

# Look up a single photo by fingerprint

`GET /v2/lookup`

## Request

- Base URL: `https://api.phototology.com`
- URL: `https://api.phototology.com/v2/lookup`
- Auth: HTTP bearer

Fast-path single-photo registry lookup for when you already hold a fingerprint. Free, no credits charged. Provide exactly one of `sha256` (exact match) or `pHash` (perceptual match within `threshold`, default 5, max 64; a 64-character bit string as returned by analyze and lookup, or 16 hex characters).

### When to use
Reach for this (instead of `POST /v2/lookup`) when you have already computed the SHA-256 or pHash and want to skip re-sending the image bytes. Like the POST form, call it before `POST /v2/analyze` to reuse a prior result for free.

### Response shape
Returns the same `LookupResponse` as the POST form: `results` keyed by the submitted fingerprint, each carrying the full `PhotoRecord` whose `lenses` map holds every cached lens output (`output`, `version`, `producedAt`, `coRunHash`, `provider`). A `none` match omits `photo`.

## Query parameters

- `sha256` string
- `pHash` string: Perceptual hash: 64-character bit string as returned by analyze and lookup, or 16 hex characters.
- `threshold` integer, nullable

## Response `200`

Lookup complete. Results keyed by the submitted fingerprint.

- object
  - `object` 'lookup', required
  - `results` object, required
  - `meta` object, required
    - `imagesSubmitted` integer, required
    - `imagesMatched` integer, required
    - `processingTimeMs` integer, required
    - `requestId` string, required

## Other responses

- `400`: Validation failed: missing both `sha256` and `pHash`, or malformed fingerprint.
- `401`: Missing or invalid API key.
- `429`: Lookup rate limit exceeded (300 req/min per key).

---

[API](https://skmtc.dev/phototology/apis/phototology-api.md) · [All operations](https://skmtc.dev/phototology/apis/phototology-api/llms.txt) · [OpenAPI document](https://skmtc.dev/phototology/apis/phototology-api/revisions/3cb0fc707b63?raw)