# bioRxiv API

> bioRxiv returns bioRxiv and medRxiv preprint data as a workflow and API.

Search preprints finds bioRxiv and medRxiv preprints matching topic words in titles, abstracts, and subject categories. Provide topic words and optionally a server, posting date range, and result limit; results appear newest first, with journal details when available.

- Page: https://fous.com/tools/biorxiv
- Handle: `@biorxiv`
- Category: [Science](https://fous.com/tools/category/science)
- Source website: https://biorxiv.org
- Last verified: Sep 29, 2026

## Methods

### Search preprints

Operation `search_preprints`, version 1. 1 credit per completed call. Failed calls without a completed billing receipt are free; completed work can remain charged if delivery is interrupted.

Find bioRxiv and medRxiv preprints matching topic words within a posting date range, newest first. Published journal details appear when available.

**Input**

| Field | Type | Required | Example | Description |
|---|---|---|---|---|
| `query` | string | yes | `"breast cancer"` | Topic words to find in preprint titles, abstracts, and subject categories, for example gut microbiome depression. |
| `server` | string | no | `"medrxiv"` | Preprint server to search, for example both. |
| `end_date` | string | no | `"2026-09-28"` | Last posting date, inclusive, for example 2026-09-29. Defaults to today. |
| `start_date` | string | no | `"2026-09-27"` | First posting date, inclusive, for example 2026-09-01. Defaults to 30 days before today. |
| `max_results` | integer | no | `5` | Maximum number of matching preprints, for example 20. |

**Input schema**

```json
{
  "type": "object",
  "required": [
    "query"
  ],
  "properties": {
    "query": {
      "type": "string",
      "minLength": 1,
      "description": "Topic words to find in preprint titles, abstracts, and subject categories, for example gut microbiome depression.",
      "examples": [
        "breast cancer",
        "catechol dioxygenases",
        "zxqvunlikelyterm47911"
      ]
    },
    "server": {
      "enum": [
        "both",
        "biorxiv",
        "medrxiv"
      ],
      "type": "string",
      "default": "both",
      "description": "Preprint server to search, for example both.",
      "examples": [
        "medrxiv",
        "biorxiv",
        "both"
      ]
    },
    "end_date": {
      "type": "string",
      "format": "date",
      "description": "Last posting date, inclusive, for example 2026-09-29. Defaults to today.",
      "examples": [
        "2026-09-28",
        "2022-01-02"
      ]
    },
    "start_date": {
      "type": "string",
      "format": "date",
      "description": "First posting date, inclusive, for example 2026-09-01. Defaults to 30 days before today.",
      "examples": [
        "2026-09-27",
        "2022-01-01"
      ]
    },
    "max_results": {
      "type": "integer",
      "default": 20,
      "maximum": 100,
      "minimum": 1,
      "description": "Maximum number of matching preprints, for example 20.",
      "x-fous-developer": true,
      "examples": [
        5
      ]
    }
  },
  "additionalProperties": false,
  "examples": [
    {
      "query": "breast cancer",
      "server": "medrxiv",
      "end_date": "2026-09-28",
      "start_date": "2026-09-27",
      "max_results": 5
    },
    {
      "query": "catechol dioxygenases",
      "server": "biorxiv",
      "end_date": "2022-01-02",
      "start_date": "2022-01-01",
      "max_results": 5
    },
    {
      "query": "zxqvunlikelyterm47911",
      "server": "both",
      "end_date": "2026-09-28",
      "start_date": "2026-09-27"
    }
  ]
}
```

**Output**

| Field | Type | Example | Description |
|---|---|---|---|
| `preprints` | array |  | Matching preprints, newest first. |
| `preprints[].doi` | string | `"10.64898/2026.09.25.26364003"` | Preprint DOI. |
| `preprints[].title` | string | `"Pixel-Level Quantification of Subcutaneous Shear-Wave Velocity Heterogeneity for Grading Lymphatic Obstruction in Breas` | Preprint title. |
| `preprints[].server` | string | `"medRxiv"` | bioRxiv or medRxiv. |
| `preprints[].authors` | string | `"Hoe, Z. Y.; Chou, C.-P.; Tzeng, Y.-D.; Ding, R.-S.; Pan, C.-T.; Lee, M.-C.; Lee, C.-H."` | Authors as credited by the preprint server. |
| `preprints[].journal` | string or null | `"G3: Genes\|Genomes\|Genetics"` | Journal name if subsequently published. |
| `preprints[].abstract` | string |  | Plain-text abstract. |
| `preprints[].pdf_link` | string | `"https://www.medrxiv.org/content/10.64898/2026.09.25.26364003v0.full.pdf"` | Direct link to the preprint PDF. |
| `preprints[].date_posted` | string | `"2026-09-28"` | Date this version was posted. |
| `preprints[].journal_link` | string or null | `"https://doi.org/10.1093/g3journal/jkac008"` | Published journal article link if available. |
| `preprints[].preprint_link` | string | `"https://www.medrxiv.org/content/10.64898/2026.09.25.26364003v0"` | Page for this preprint version. |
| `preprints[].subject_category` | string or null | `"radiology and imaging"` | Subject area. |

**Example input**

```json
{
  "query": "breast cancer",
  "server": "medrxiv",
  "end_date": "2026-09-28",
  "start_date": "2026-09-27",
  "max_results": 5
}
```

**Example output**

```json
{
  "preprints": [
    {
      "doi": "10.64898/2026.09.25.26364003",
      "title": "Pixel-Level Quantification of Subcutaneous Shear-Wave Velocity Heterogeneity for Grading Lymphatic Obstruction in Breast Cancer-Related Lymphedema",
      "server": "medRxiv",
      "authors": "Hoe, Z. Y.; Chou, C.-P.; Tzeng, Y.-D.; Ding, R.-S.; Pan, C.-T.; Lee, M.-C.; Lee, C.-H.",
      "journal": null,
      "abstract": "Objectives: To develop and validate pixel data analysis (PDA) for reconstructing pixel-level shear-wave velocity (SWV) from saved Holder-Optimized Elastography (HOE) elastograms and to determine wheth…",
      "pdf_link": "https://www.medrxiv.org/content/10.64898/2026.09.25.26364003v0.full.pdf",
      "date_posted": "2026-09-28",
      "journal_link": null,
      "preprint_link": "https://www.medrxiv.org/content/10.64898/2026.09.25.26364003v0",
      "subject_category": "radiology and imaging"
    },
    {
      "doi": "10.64898/2026.09.08.26362522",
      "title": "Epigenetic misprogramming of cell differentiation links transient viral infection to chronic diseases across tissues",
      "server": "medRxiv",
      "authors": "Friedenson, B.",
      "journal": null,
      "abstract": "Virus-induced epigenetic changes in stem-cell differentiation pathways emerge here as a shared mechanism linking fundamentally different chronic diseases, offering candidate biomarkers and new interve…",
      "pdf_link": "https://www.medrxiv.org/content/10.64898/2026.09.08.26362522v0.full.pdf",
      "date_posted": "2026-09-28",
      "journal_link": null,
      "preprint_link": "https://www.medrxiv.org/content/10.64898/2026.09.08.26362522v0",
      "subject_category": "genetic and genomic medicine"
    }
  ]
}
```

## Quick start

Replace `YOUR_API_KEY` with a Fous API key. To create one, open Developers at the bottom of Fous Studio, turn on Developer mode, then go to API keys (https://app.fous.com/keys). Change the values in `input` to run the same tool on new data.

```bash
curl 'https://api.fous.com/v1/query' \
  --fail-with-body --silent --show-error --max-time 180 \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H 'Content-Type: application/json' \
  --data-raw '{
  "api": "@biorxiv",
  "visibility": "public",
  "operation": "search_preprints",
  "version": 1,
  "input": {
    "query": "breast cancer",
    "server": "medrxiv",
    "end_date": "2026-09-28",
    "start_date": "2026-09-27",
    "max_results": 5
  },
  "response": {
    "format": "json"
  }
}'
```

```python
# Save as fous.py and run with python3 fous.py. No packages needed.
import json
import urllib.error
import urllib.request

api_key = "YOUR_API_KEY"

body = json.loads("{\n  \"api\": \"@biorxiv\",\n  \"visibility\": \"public\",\n  \"operation\": \"search_preprints\",\n  \"version\": 1,\n  \"input\": {\n    \"query\": \"breast cancer\",\n    \"server\": \"medrxiv\",\n    \"end_date\": \"2026-09-28\",\n    \"start_date\": \"2026-09-27\",\n    \"max_results\": 5\n  },\n  \"response\": {\n    \"format\": \"json\"\n  }\n}")
request = urllib.request.Request(
    "https://api.fous.com/v1/query",
    data=json.dumps(body).encode("utf-8"),
    headers={
        "Authorization": f"Bearer {api_key}",
        "Content-Type": "application/json",
    },
    method="POST",
)
try:
    with urllib.request.urlopen(request, timeout=180) as response:
        result = json.load(response)
except urllib.error.HTTPError as error:
    raise RuntimeError(f"HTTP {error.code}: {error.read().decode('utf-8', errors='replace')}") from error
if result.get("success") is False:
    raise RuntimeError(result.get("error", {}).get("message", "Request failed"))
print(json.dumps(result["data"]["output"], indent=2))
```

```typescript
// Save as fous.mts and run with npx tsx fous.mts.
const apiKey = "YOUR_API_KEY";

const response = await fetch("https://api.fous.com/v1/query", {
  method: "POST",
  headers: {
    "Authorization": `Bearer ${apiKey}`,
    "Content-Type": "application/json",
  },
  signal: AbortSignal.timeout(180_000),
  body: JSON.stringify({
  "api": "@biorxiv",
  "visibility": "public",
  "operation": "search_preprints",
  "version": 1,
  "input": {
    "query": "breast cancer",
    "server": "medrxiv",
    "end_date": "2026-09-28",
    "start_date": "2026-09-27",
    "max_results": 5
  },
  "response": {
    "format": "json"
  }
}),
});
type ApiResult = { success: boolean; data?: { output: unknown }; error?: { message: string } };
const result: ApiResult = await response.json();
if (!response.ok || result.success === false) {
  throw new Error(result.error?.message ?? `HTTP ${response.status}`);
}
if (!result.data) throw new Error("Missing API response data");
console.log(result.data.output);
```

## Use from an AI assistant

Connect this tool to Claude Code, Claude Desktop, Cursor, VS Code, Codex and any MCP client as its own MCP server. Each method is a typed tool whose arguments are the method’s input.

- Server URL: `https://api.fous.com/mcp/tools/biorxiv`
- Authorization: `Authorization: Bearer <Fous API key>`

**Tools**

- `search_preprints`: Search preprints. 1 credit per completed call. Failed calls without a completed billing receipt are free; completed work can remain charged if delivery is interrupted.
- `fous_get_run`: the result of a run that was still going, by its `request_id`. Free.

Claude Code:

```bash
claude mcp add --scope user --transport http fous-biorxiv https://api.fous.com/mcp/tools/biorxiv --header "Authorization: Bearer ${FOUS_API_KEY:?Set FOUS_API_KEY to your Fous API key}"
```

To give the assistant every tool, connect `https://api.fous.com/mcp`: it finds one with `fous_search_tools` and runs it with `fous_run_tool`. Setup for other clients: https://fous.com/llms-full.txt.

## Use cases

- Track new preprints on a research topic
- Review preprint abstracts and author lists
- Find preprints by posting date and subject area
- Identify preprints with published journal details

## FAQ

### Can I run it with my own inputs?

Yes. Change the inputs in Studio and press Run, or send new inputs from your code, or ask a connected AI assistant.

### Can I call this bioRxiv tool as an API?

Yes. Send a POST request to /v1/query with your Fous API key and the inputs, and get JSON back.

### How much does it cost?

Each completed run costs 1 credit. Failed runs without a completed receipt are free; completed work can remain charged if delivery is interrupted. With pay as you go, a credit costs 1¢. Monthly plans cost less per credit.

### Do I need a bioRxiv account?

No. You only need a Fous account.

### How current is the data?

Fous gets the data from biorxiv.org when you run it. Some results are reused for up to 24 hours, and results that use your account or key are never reused. It was last verified on Sep 29, 2026.

### Which preprints match my research topic?

Search preprints finds preprints matching topic words in titles, abstracts, and subject categories.

### When was a preprint posted?

Search preprints returns the posting date for each matching version.

### Has a preprint been published in a journal?

Search preprints includes journal details and a journal article link when available.

## Related

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- [All Science tools](https://fous.com/tools/category/science)