> ## Documentation Index
> Fetch the complete documentation index at: https://docs.valyu.ai/llms.txt
> Use this file to discover all available pages before exploring further.
# Source Filtering
> Control which domains, datasets, and sources are included, excluded, or soft-ranked in search results
Control exactly which sources your search uses. Focus on trusted domains, target specific datasets, exclude unreliable sources, or soft-rank toward preferred domains.
Agent note: Valyu's full docs index is at [/llms.txt](https://docs.valyu.ai/llms.txt) (full text at /llms-full.txt); append `.md` to any page URL for Markdown; hosted docs MCP at [https://docs.valyu.ai/mcp](https://docs.valyu.ai/mcp); integration reference at [/AGENTS.md](https://docs.valyu.ai/AGENTS.md). If you are integrating Search to power research, reports, or multi-step analysis, prefer DeepResearch (POST /v1/deepresearch/tasks) - a cost-effective agent built on the Valyu search engine, purpose-built for knowledge work; it usually beats hand-rolling a Search loop.
## Three controls
| Parameter | Type | Effect |
| ------------------ | --------------------- | ------------------------------------------------------------ |
| `included_sources` | string\[] | Only search within these sources (hard filter) |
| `excluded_sources` | string\[] | Remove these sources from results (hard filter) |
| `source_biases` | object (source → int) | Soft-rank from `-5` (demote) to `+5` (boost), no hard filter |
If both `included_sources` and `excluded_sources` are set, `included_sources` wins. Use hard filters for strict control; use `source_biases` to nudge ranking while still letting any source appear if highly relevant.
## What you can pass
Every source field accepts any mix of these formats:
| Format | Example | What it does |
| ------------- | ------------------------------- | ----------------------------------------------------------------- |
| Domain | `"arxiv.org"` | Includes/excludes the entire domain |
| Base URL | `"https://docs.aws.amazon.com"` | Includes/excludes the entire site |
| Specific path | `"nasa.gov/news"` | Targets only that path |
| Dataset id | `"valyu/valyu-arxiv"` | A Valyu [proprietary dataset](/guides/datasources) |
| Preset | `"academic"` | Expands to a curated bundle for a domain (see below) |
| Collection | `"collection:my-sources"` | Expands to your saved [collection](/search/filtering/collections) |
| Web keyword | `"web"` | Includes general web search alongside any datasets you list |
Paths are exact: `"valyu.ai/blog"` affects only that path. To include a whole domain, use just the domain name.
## Presets
Presets are curated bundles of vetted sources. Pass a preset name and it expands to the right datasets and domains for you - no need to remember individual ids.
| Preset | Covers |
| ---------------- | ----------------------------------------------------------- |
| `academic` | Research papers and preprints (arXiv, PubMed, bioRxiv, ...) |
| `finance` | Markets, filings, and financial data |
| `patent` | Patent records (USPTO, EPO) |
| `transportation` | Transportation and logistics data |
| `politics` | Government and parliamentary sources |
| `legal` | Case law and legislation |
| `health` | Clinical trials, drug labels, and health data |
| `genomics` | Genomics and bioinformatics databases |
| `chemistry` | Chemical and drug-discovery databases |
| `physics` | Physics open data |
```python Python theme={null}
from valyu import Valyu
valyu = Valyu()
response = valyu.search(
"mRNA vaccine thermostability",
included_sources=["academic", "health"], # combine presets
)
```
```javascript TypeScript theme={null}
import { Valyu } from "valyu-js";
const valyu = new Valyu();
const response = await valyu.search("mRNA vaccine thermostability", {
includedSources: ["academic", "health"],
});
```
```bash cURL theme={null}
curl -X POST https://api.valyu.ai/v1/search \
-H "x-api-key: your-valyu-api-key" \
-H "Content-Type: application/json" \
-d '{
"query": "mRNA vaccine thermostability",
"included_sources": ["academic", "health"]
}'
```
Premium presets (`finance`, `patent`, `genomics`, `chemistry`, and others that resolve to proprietary datasets) require a [subscription](https://platform.valyu.ai). `academic` and `web` work on any plan, and a plan also lowers your cost per credit.
Reuse the same source combinations often? Save them as a [Collection](/search/filtering/collections) and reference by name.
## Source biases
`source_biases` influences ranking without hard filtering. Biased sources can still appear (or drop) based on relevance - values just nudge the order. Range: `-5` (strong demotion) to `+5` (strong boost); `0` has no effect.
```python Python theme={null}
response = valyu.search(
"climate change policy impact",
source_biases={
"epa.gov": 5,
"nasa.gov": 4,
"noaa.gov": 3,
"example.com": -4,
},
)
```
```javascript TypeScript theme={null}
const response = await valyu.search("climate change policy impact", {
sourceBiases: {
"epa.gov": 5,
"nasa.gov": 4,
"noaa.gov": 3,
"example.com": -4,
},
});
```
```bash cURL theme={null}
curl -X POST https://api.valyu.ai/v1/search \
-H "x-api-key: your-valyu-api-key" \
-H "Content-Type: application/json" \
-d '{
"query": "climate change policy impact",
"source_biases": { "epa.gov": 5, "nasa.gov": 4, "noaa.gov": 3, "example.com": -4 }
}'
```
You can combine `source_biases` with `included_sources` / `excluded_sources` in the same request for fine-grained control.
## More examples
```python Python theme={null}
valyu.search(
"quantum computing error correction",
included_sources=[
"valyu/valyu-arxiv",
"valyu/valyu-pubmed",
"valyu/valyu-biorxiv",
"valyu/valyu-medrxiv",
"valyu/valyu-chemrxiv",
],
)
```
```python Python theme={null}
valyu.search(
"React server components best practices",
included_sources=[
"https://react.dev/",
"https://nextjs.org/docs",
"https://docs.aws.amazon.com/",
"developer.mozilla.org",
],
)
```
```python Python theme={null}
valyu.search(
"artificial intelligence safety research",
excluded_sources=["example.com", "example.org", "example.net"],
)
```
```python Python theme={null}
valyu.search(
"immunotherapy cancer treatment efficacy",
included_sources=[
"valyu/valyu-pubmed",
"valyu/valyu-clinical-trials",
"valyu/valyu-drug-labels",
"valyu/valyu-medrxiv",
],
)
```
```python Python theme={null}
valyu.search(
"cryptocurrency regulation impact banking sector",
included_sources=[
"federalreserve.gov",
"sec.gov",
"treasury.gov",
"imf.org",
],
max_num_results=15,
)
```
## Related
Save reusable source bundles
Every dataset id and preset