# HeartRails Geo API – Japan Municipalities by Prefecture

> HeartRails Geo API – Japan Municipalities by Prefecture is a paid API for AI agents from clonecho.builda.company, paid per call via x402, $0.02/call, status unknown (last checked 2026-09-14).

Returns a list of municipalities (cities/wards) within a specified Japanese prefecture, keyed by prefecture name in Japanese.

## Facts

- Endpoint: POST https://clonecho.builda.company/x402/s/heartrails-jp-cities
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/heartrails-geo-api-japan-municipalities-by-prefecture-3117752d
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_V76hKhwrdVwoS-3diM5tL

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability heartrails-geo-api-japan-municipalities-by-prefecture-3117752d -d '<json body>'
```

Example prompt: Can you get me a list of all municipalities and cities within Osaka prefecture in Japan?

## When to prefer this

Use this endpoint when you need to enumerate municipalities, cities, or wards within a specific Japanese prefecture by name. Ideal for building location pickers, validating Japanese addresses, or enriching data with administrative geography for Japan.

## Known failure modes

- Invalid or misspelled prefecture name returns empty or error result
- Missing ?q= parameter may return an error or empty response
- Non-Japanese prefecture name may not be recognized
- API may return unexpected structure if HeartRails upstream changes

## How this service works

Japan (HeartRails Geo API): municipalities (cities/wards) within a prefecture, keyed by Japanese prefecture name. Query: ?q= Returns JSON.

## Output

A JSON object containing a list of municipalities (cities, wards, towns) located within the specified Japanese prefecture, keyed by prefecture name.

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/heartrails-geo-api-japan-municipalities-by-prefecture-3117752d/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from clonecho.builda.company](https://www.zero.xyz/host/clonecho.builda.company/llms.txt)