# Library of Congress — Wrapped API

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>
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> | Environment | Landing | API | Docs |
> |---|---|---|---|
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> | Beta | beta.paywithlocus.com | api.beta.paywithlocus.com | docs.paywithlocus.com |
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> Search the Library of Congress collection of historical Sanborn Fire Insurance Maps by location to find map sheets with their titles, dates, and high-resolution images. Access detailed metadata and download links for maps covering specific areas and time periods.

**Category:** Government & Public Data | **Website:** [www.loc.gov/collections/sanborn-maps/](https://www.loc.gov/collections/sanborn-maps/) | **Docs:** [parse.bot/marketplace/694e5dee-0b76-49ac-be8e-e686480da6c5/loc-gov-api](https://parse.bot/marketplace/694e5dee-0b76-49ac-be8e-e686480da6c5/loc-gov-api)

Pay-per-use API proxy for Locus Pro. Each call burns credits from your workspace balance.

## Access

**Base URL:** `https://api.beta.paywithlocus.com/api/wrapped/credits/library-of-congress/`
**Auth:** `Authorization: Bearer <LOCUS_CREDITS_SECRET_KEY>` (an `lcr_` secret key or a scoped `lcac_` agent credential)
**Required header:** `Idempotency-Key: <fresh UUID per call>`. A retry with the same key replays the stored result without a new charge.
**Response:** the provider response after any endpoint-specific normalization. `X-Locus-Credits-Charged` carries the charge and `X-Locus-Credits-Balance` the remaining balance. Insufficient credits return `402` before the provider is called.
**Pricing:** estimated costs below are USD. Locus debits the credit equivalent at your workspace rate.

Full call contract: https://docs.paywithlocus.com/api-reference/introduction

> Using a Pay With Locus wallet key (`claw_` prefix)? Wallet routes are documented separately: https://docs.paywithlocus.com/wrapped-apis/for-agents

## Endpoints

### List sanborn sheets

List Sanborn fire insurance map sheets filtered by location. Returns paginated results from the Library of Congress Sanborn Maps collection with metadata and highest-resolution IIIF image URLs for each sheet.

**Estimated cost:** Metered

| Field | Type | Required | Description |
|-------|------|----------|-------------|
| `location` | string | No | City name to filter maps by (e.g. 'san francisco', 'boston', 'new york'). Used as a location facet filter. |
| `page` | integer | No | Page number for pagination. Must be a positive integer. |
| `per_page` | integer | No | Number of results per page. Must be between 1 and 150. |
| `state` | string | No | State name to filter maps by (e.g. 'california', 'massachusetts'). Combined with location for more precise filtering. |

```bash
curl -X POST https://api.beta.paywithlocus.com/api/wrapped/credits/library-of-congress/list-sanborn-sheets \
  -H "Authorization: Bearer $LOCUS_CREDITS_SECRET_KEY" \
  -H "Idempotency-Key: $(uuidgen)" \
  -H "Content-Type: application/json" \
  -d '{"location":"<string>","page":"<integer>","per_page":"<integer>","state":"<string>"}'
```

## Next steps

- [All wrapped API providers](https://beta.paywithlocus.com/wapi/index.md): pick another provider.
- [Find and call tools](https://beta.paywithlocus.com/agent/tools.md): price ceilings, async results, and errors.
- [Credits and billing](https://beta.paywithlocus.com/agent/billing.md): what a call costs and how to add credits.
- [Agent docs index](https://beta.paywithlocus.com/agent/index.md): every Locus agent page.