# Research Index

> Search papers, read paper passages, and find related work

Firecrawl Research is a purpose-built index for scientific and engineering research agents. It exposes a research-specific toolset for searching papers, inspecting paper metadata, reading relevant full-text passages, and discovering related papers through structural expansion.

The index covers roughly 43 million paper abstracts. The majority of the corpus is biomedical and life sciences — **PubMed**, **bioRxiv**, and **medRxiv** — alongside **arXiv** for physics, mathematics, and computer science. Papers are addressable by their source ids, so `pmid:`, `pmcid:`, and `doi:` references work the same way `arxiv:` ones do.

- Find papers by topic, method, benchmark, author, or category
- Inspect canonical paper metadata and source ids
- Read the passages in one paper that answer a specific question
- Expand from strong seed papers to related papers, citers, or references

<Note>
To give your agent access to the Research Index, we strongly recommend using our [CLI](/sdks/cli) or [MCP](/mcp-server), combined with our [**dedicated research skill**](https://github.com/firecrawl/skills/blob/main/skills/firecrawl-research-index/SKILL.md), which you can install with:
```bash
npx skills add firecrawl/skills@firecrawl-research-index
```
</Note>

## How this relates to `/search`

Firecrawl has two things named "research", and they are not the same feature:

| | Research Index (this page) | `/search` with `categories: ["research"]` |
| :-- | --- | --- |
| What it searches | A paper index of ~43M abstracts — PubMed, bioRxiv, medRxiv, arXiv | The open web, restricted to ~14 academic **websites** (arxiv.org, nature.com, pubmed.ncbi.nlm.nih.gov, …) |
| What you get back | Ranked paper records: canonical `paperId`, `primaryId`, source ids, title, full abstract, score | Ordinary web results: URL, title, snippet |
| Can it read inside a paper | Yes — passage-level reads via `GET /search/research/papers/{id}` | No |
| Can it expand by citations | Yes — `GET /search/research/papers/{id}/similar` | No |
| Endpoint | `GET /search/research/papers` | `POST /search` |

Use the Research Index when you are doing literature work: finding papers, reading them, and following citations. Use [`categories: ["research"]`](/features/search#search-categories) when you want ordinary web pages that happen to live on academic domains.

## Endpoints

| Task | Endpoint |
| --- | --- |
| Search papers | [`GET /search/research/papers`](/api-reference/endpoint/research-search-papers) |
| Inspect metadata or read passages | [`GET /search/research/papers/{id}`](/api-reference/endpoint/research-paper) |
| Find related papers | [`GET /search/research/papers/{id}/similar`](/api-reference/endpoint/research-related-papers) |

## Search papers

Search paper abstracts with a natural-language query. The response returns ranked papers with canonical `paperId`, preferred `primaryId`, source ids, title, abstract, score, and optional ranking signals.

<CodeGroup>

```bash cURL
# No API key needed to get started; add -H "Authorization: Bearer $FIRECRAWL_API_KEY" for higher rate limits:
curl -s "https://api.firecrawl.dev/v2/search/research/papers?query=diffusion%20image%20synthesis&k=20"
```

```bash CLI
firecrawl research search-papers "diffusion image synthesis" --limit 20
```

```python Python
from firecrawl import Firecrawl

firecrawl = Firecrawl(
  # No API key needed to get started; add one for higher rate limits:
  # api_key="fc-YOUR-API-KEY",
)

result = firecrawl.v2.search_papers("diffusion image synthesis", k=20)
print(result)
```

```js Node
import { Firecrawl } from "firecrawl";

const firecrawl = new Firecrawl({
  // No API key needed to get started; add one for higher rate limits:
  // apiKey: "fc-YOUR-API-KEY",
});

const result = await firecrawl.research.searchPapers("diffusion image synthesis", {
  k: 20,
});
console.log(result);
```

</CodeGroup>

Optional filters:

- `authors`: author substring filter; all filters must match
- `categories`: paper category filter, such as `cs.LG`
- `from`: inclusive created/updated lower bound, `YYYY-MM-DD`
- `to`: inclusive created/updated upper bound, `YYYY-MM-DD`

### Biomedical example

Most of the index is life sciences, so clinical and molecular biology queries work the same way:

<CodeGroup>

```bash cURL
# No API key needed to get started; add -H "Authorization: Bearer $FIRECRAWL_API_KEY" for higher rate limits:
curl -s "https://api.firecrawl.dev/v2/search/research/papers?query=CRISPR%20base%20editing%20off-target%20effects%20in%20primary%20human%20T%20cells&k=20"
```

```bash CLI
firecrawl research search-papers "CRISPR base editing off-target effects in primary human T cells" --limit 20
```

```python Python
from firecrawl import Firecrawl

firecrawl = Firecrawl(
  # No API key needed to get started; add one for higher rate limits:
  # api_key="fc-YOUR-API-KEY",
)

result = firecrawl.v2.search_papers(
  "CRISPR base editing off-target effects in primary human T cells",
  k=20,
)
print(result)
```

```js Node
import { Firecrawl } from "firecrawl";

const firecrawl = new Firecrawl({
  // No API key needed to get started; add one for higher rate limits:
  // apiKey: "fc-YOUR-API-KEY",
});

const result = await firecrawl.research.searchPapers(
  "CRISPR base editing off-target effects in primary human T cells",
  { k: 20 },
);
console.log(result);
```

</CodeGroup>

Results carry a `primaryId` in whichever namespace the source uses, so biomedical hits come back as `pmid:<id>`, `pmcid:<id>`, or `doi:<doi>`. Feed that value straight back into the inspect, read, and related endpoints below.

## Inspect a paper

Use a canonical `paperId` or a source-specific `primaryId`. Accepted `primaryId` forms are `arxiv:<id>`, `pmid:<id>`, `pmcid:<id>`, and `doi:<doi>` — for example `curl -s ".../v2/search/research/papers/pmid:<id>"` for a PubMed record.

<CodeGroup>

```bash cURL
# No API key needed to get started; add -H "Authorization: Bearer $FIRECRAWL_API_KEY" for higher rate limits:
curl -s "https://api.firecrawl.dev/v2/search/research/papers/arxiv:1706.03762"
```

```bash CLI
firecrawl research inspect-paper arxiv:1706.03762
```

```python Python
from firecrawl import Firecrawl

firecrawl = Firecrawl(
  # No API key needed to get started; add one for higher rate limits:
  # api_key="fc-YOUR-API-KEY",
)

paper = firecrawl.v2.inspect_paper("arxiv:1706.03762")
print(paper)
```

```js Node
import { Firecrawl } from "firecrawl";

const firecrawl = new Firecrawl({
  // No API key needed to get started; add one for higher rate limits:
  // apiKey: "fc-YOUR-API-KEY",
});

const paper = await firecrawl.research.getPaper("arxiv:1706.03762");
console.log(paper);
```

</CodeGroup>

## Read paper passages

Add `query` to the same paper path to retrieve the top full-text passages for a question. This is useful for verifying whether a candidate paper actually contains a method, dataset, constraint, or result before you include it.

<CodeGroup>

```bash cURL
# No API key needed to get started; add -H "Authorization: Bearer $FIRECRAWL_API_KEY" for higher rate limits:
curl -s "https://api.firecrawl.dev/v2/search/research/papers/arxiv:1706.03762?query=what%20is%20the%20attention%20mechanism&k=4"
```

```bash CLI
firecrawl research read-paper arxiv:1706.03762 --question "What is the attention mechanism?" --limit 4
```

```python Python
from firecrawl import Firecrawl

firecrawl = Firecrawl(
  # No API key needed to get started; add one for higher rate limits:
  # api_key="fc-YOUR-API-KEY",
)

passages = firecrawl.v2.read_paper(
    "arxiv:1706.03762",
    "What is the attention mechanism?",
    k=4,
)
print(passages)
```

```js Node
import { Firecrawl } from "firecrawl";

const firecrawl = new Firecrawl({
  // No API key needed to get started; add one for higher rate limits:
  // apiKey: "fc-YOUR-API-KEY",
});

const passages = await firecrawl.research.getPaper("arxiv:1706.03762", {
  query: "What is the attention mechanism?",
  k: 4,
});
console.log(passages);
```

</CodeGroup>

## Find related papers

Expand from one or more seed papers through semantic expansion and rank the candidates against a natural-language `intent`.

<CodeGroup>

```bash cURL
# No API key needed to get started; add -H "Authorization: Bearer $FIRECRAWL_API_KEY" for higher rate limits:
curl -s "https://api.firecrawl.dev/v2/search/research/papers/arxiv:1706.03762/similar?intent=efficient%20transformers&mode=similar&k=20"
```

```bash CLI
firecrawl research related-papers arxiv:1706.03762 --intent "efficient transformers" --limit 20
```

```python Python
from firecrawl import Firecrawl

firecrawl = Firecrawl(
  # No API key needed to get started; add one for higher rate limits:
  # api_key="fc-YOUR-API-KEY",
)

papers = firecrawl.v2.related_papers(
    "arxiv:1706.03762",
    "efficient transformers",
    mode="similar",
    k=20,
)
print(papers)
```

```js Node
import { Firecrawl } from "firecrawl";

const firecrawl = new Firecrawl({
  // No API key needed to get started; add one for higher rate limits:
  // apiKey: "fc-YOUR-API-KEY",
});

const papers = await firecrawl.research.similarPapers("arxiv:1706.03762", {
  intent: "efficient transformers",
  mode: "similar",
  k: 20,
});
console.log(papers);
```

</CodeGroup>

Modes:

- `similar`: co-citation and bibliographic-coupling neighborhood
- `citers`: papers that cite the seed
- `references`: papers cited by the seed