# Reverse API — Vietmap API Playground

> Identify location from coordinates with Vietmap Reverse API.

The Reverse Geocoding API works the other way round: from a coordinate it returns the nearest address and place name. Version 4 has display_type to return the address under the new administrative units, the old ones, or both — useful when the data has to match a system still on the former boundaries. It usually follows a device GPS fix or a tap on the map.

What it is for:
- Showing the current address of a driver or courier.
- Pre-filling an address when the user picks a point on the map.
- Labelling GPS logs or field photos with an address.
- Finding the province or ward of a location for pricing.

- Interactive page: https://tools.vietmap.vn/playground/en/reverse
- Endpoint: `GET /api/reverse/v4` on `https://maps.vietmap.vn` (trang có tuỳ chọn chuyển sang v3)
- Official documentation: https://maps.vietmap.vn/docs/map-api/reverse-version/reverse-v4/
- API key: every request needs the `apikey` parameter. Samples use `YOUR_API_KEY` as the placeholder — when integrating, read the key from an environment variable (e.g. `VIETMAP_API_KEY`). Get a key at https://maps.vietmap.vn/console-v2/consumers
- Error codes: `401` wrong API key · `403` key restricted to another domain/IP · `423` API not enabled for the key's consumer, or out of credit (body contains "exceeded credit") · `429` rate limit exceeded.

## Code samples

### cURL

```bash
curl 'https://maps.vietmap.vn/api/reverse/v4?apikey=YOUR_API_KEY&lat=10.7778046&lng=106.7019192&display_type=6'
```

### JavaScript

```javascript
// In production, read the key from an environment variable instead.
const API_KEY = "YOUR_API_KEY";

const params = new URLSearchParams([
  ["apikey", API_KEY],
  ["lat", "10.7778046"],
  ["lng", "106.7019192"],
  ["display_type", "6"],
]);

const response = await fetch(`https://maps.vietmap.vn/api/reverse/v4?${params}`);
if (!response.ok) {
  throw new Error(`Vietmap ${response.status}: ${await response.text()}`);
}
const data = await response.json();
console.log(data);
```

### Python

```python
import requests

# In production, read the key from an environment variable instead.
API_KEY = "YOUR_API_KEY"

params = [
    ("apikey", API_KEY),
    ("lat", "10.7778046"),
    ("lng", "106.7019192"),
    ("display_type", "6"),
]

response = requests.get("https://maps.vietmap.vn/api/reverse/v4", params=params, timeout=30)
response.raise_for_status()
print(response.json())
```

### URL

```text
https://maps.vietmap.vn/api/reverse/v4?apikey=YOUR_API_KEY&lat=10.7778046&lng=106.7019192&display_type=6
```

## AI prompt

A ready-made prompt for a coding assistant (ChatGPT, Claude, Copilot…) to write the integration:

````text
I need to integrate Vietmap's Reverse API v4 into my application.

Official documentation: https://maps.vietmap.vn/docs/map-api/reverse-version/reverse-v4/

Here is a sample request that works in the Vietmap API Playground:

GET https://maps.vietmap.vn/api/reverse/v4?apikey=YOUR_API_KEY&lat=10.7778046&lng=106.7019192&display_type=6

Parameters in use:
- lat = 10.7778046
- lng = 106.7019192
- display_type = 6

Write code in [my language / framework] that calls this API, with these requirements:
1. Read the API key from the VIETMAP_API_KEY environment variable; never hard-code it.
2. Send the parameters in the query string exactly as in the sample; repeated parameters (such as `point`) must keep their order.
3. Handle Vietmap's HTTP errors:
   - 401: the API key is wrong or revoked.
   - 403: the key is restricted to a domain / IP that does not match.
   - 423: the API is not enabled for the key's consumer, OR the account is out of credit — tell them apart by the response body ("exceeded credit" means out of credit).
   - 429: rate limit exceeded — retry with increasing backoff.
4. Set a request timeout, and define types (type / interface / dataclass) for the response.

If unsure about a field name, look it up in the documentation linked above instead of guessing.
````

## Reopen this exact request in the Playground

https://tools.vietmap.vn/playground/en/reverse?lat=10.7778046&lng=106.7019192&version=v4&display_type=6