> ## Documentation Index
> Fetch the complete documentation index at: https://docs.terrapinfinance.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Welcome to Terrapin

> The modern fixed-income data API.

[Terrapin](https://terrapinfinance.com) is a modern fixed-income data company, providing access to reference and pricing data, as well as official statements and disclosure documents.

## Coverage

| Universe                            | Approx. coverage    | Endpoint prefix    |
| ----------------------------------- | ------------------- | ------------------ |
| Global government & corporate bonds | \~35,000 bonds      | `/api/v1/bond_*`   |
| US agency bonds                     | \~70,000 bonds      | `/api/v1/agency_*` |
| US municipal bonds                  | \~1.2 million bonds | `/api/v1/muni_*`   |

## How endpoints are named

Endpoints follow a `{universe}_{data_type}` convention. Each universe exposes the same core data types plus a few that are specific to that market.

### Common data types

* `search`: find bonds matching filters (maturity, coupon, country, rating, etc.). Returns a compact set of fields.
* `reference`: full reference data for a list of ISINs.
* `pricing_latest`: most recent price for each ISIN.
* `pricing_history`: historical price series.
* `cashflows`: projected interest and principal schedules.

### Universe-specific endpoints

Government & corporate also exposes `inflation_factors` for inflation-linked sovereigns. See [Inflation factors](/inflation_factors).

US municipal additionally exposes:

* `entity_search`: search by issuer or obligor.
* `documents`: retrieve official statement and disclosure document keys (which can be downloaded with `/api/v1/download_document`)
* `pricing_daily_history`: a full day of trades across every ISIN at once.
* `price_to_yield`: convert between price and yield.
* `bonds_in_series`: find sibling ISINs belonging to the same series.
* `events`: corporate action history (calls, defeasances, splits, consolidations, etc).

The use of funds taxonomy used in muni reference data is documented in [Use of Funds Taxonomy](/use_of_funds_taxonomy).

### Utilities

* `convert_to_isin`: resolve a list of 9-character US CUSIPs to ISINs. Inputs that aren't valid CUSIPs come back with `isin: null`. CUSIP is the only supported input type today.
* `download_document`: fetch the content of a document returned by `muni_documents`. Files can be retrieved as PDFs (as binary stream) or text files. Today only muni disclosure documents are supported.

## Authentication, limits, errors

All endpoints require a bearer token. See [Authentication](/authentication) and [Rate limits & quotas](/rate-limits-and-quotas). Error responses use the envelope described in [Errors](/errors).

## MCP access

The same API is also available as an MCP server for Claude and ChatGPT. See [MCP access](/mcp-access).