# Check if a DOI or citation really exists

**Use case:** 

Paste DOIs or free-text citations (one per line) and see instantly whether each reference exists: verified via DOI, matched by title/year in Crossref, found on arXiv, DOI belongs to a different paper, or not found. Also flags retractions and expressions of concern (Retraction Watch data). Catches AI-invented references. $0.01 per reference.

## Input

```json
{
  "references": [
    "10.1038/nature14539",
    "Jumper J et al. Highly accurate protein structure prediction with AlphaFold. Nature 2021"
  ],
  "checkRetractions": true
}
```

## Output

```json
{
  "input": {
    "label": "input",
    "format": "text"
  },
  "inputType": {
    "label": "inputType",
    "format": "text"
  },
  "status": {
    "label": "status",
    "format": "text"
  },
  "title": {
    "label": "title",
    "format": "text"
  },
  "authors": {
    "label": "authors",
    "format": "array"
  },
  "journal": {
    "label": "journal",
    "format": "text"
  },
  "year": {
    "label": "year",
    "format": "number"
  },
  "matchConfidence": {
    "label": "matchConfidence",
    "format": "number"
  },
  "updateNotices": {
    "label": "updateNotices",
    "format": "array"
  },
  "retractedOrConcern": {
    "label": "retractedOrConcern",
    "format": "boolean"
  },
  "url": {
    "label": "url",
    "format": "link"
  }
}
```

## How it works

### 1. Sign up on Apify or log in

The Reference Verifier – DOI & Citation Checker Actor is ready to run with the inputs already set for "Check if a DOI or citation really exists". [Sign up or log in](https://console.apify.com/create-task-from-example/FnXA229zTMXbMihPJ) and you'll land in Apify Console with a copy of this exact task.

### 2. Start the "Check if a DOI or citation really exists" task

The Reference Verifier – DOI & Citation Checker Actor will start running based on the input automatically. You can also change all the input fields, like references and check retractions & corrections, to match your specific use case.

### 3. Receive the "Check if a DOI or citation really exists" output

Monitor the progress in real time. You will be notified as soon as your dataset is complete and ready for review. Each result includes data such as input, inputtype, status, and more.

### 4. Integrate into your workflow

The final output is delivered in JSON, CSV, or Excel format, ready to be plugged into your workflow. You can also [run the "Check if a DOI or citation really exists" task via API](https://apify.com/researchdata/crossref-reference-verifier.md).

## About this Actor

This example demonstrates how to use [Reference Verifier – DOI & Citation Checker](https://apify.com/researchdata/crossref-reference-verifier.md) with a specific input configuration. Visit the [Actor detail page](https://apify.com/researchdata/crossref-reference-verifier.md) to learn more, explore other use cases, and run it yourself.


## How to integrate an Actor?

This Task's input is already configured above. Use it as-is rather than inventing a new one.

Do not guess an integration path. Every one of them is in the agent quickstart at https://apify.com/agents.md: the Apify MCP server, Agent Skills with the Apify CLI, the JavaScript and Python clients, the REST API, and the account-free path for an agent with no human to sign in. It also carries the rule on stating cost before the first paid run.

For full API examples (JavaScript, Python, CLI, MCP, OpenAPI), see this Task's Actor page: https://apify.com/researchdata/crossref-reference-verifier.md

Each client library has reference documentation the quickstart does not restate: [JavaScript/TypeScript](https://docs.apify.com/api/client/js/docs.md) (`npm install apify-client`) and [Python](https://docs.apify.com/api/client/python/docs.md) (`pip install apify-client`).