---
title: "BIN Lookup API Go Guide"
description: "Call the BIN Lookup API from Go with net/http. Handle current error codes and send a batch lookup."
section: "Guides"
url: "https://binlookupapi.com/docs/guides/go/"
markdown_url: "https://binlookupapi.com/docs/guides/go.md"
---
# BIN lookup with Go

This page uses the Go standard library. Create an API key in the [quickstart](/docs/quickstart/). Read it from the environment variable `BINLOOKUP_API_KEY`.

## Look up one BIN

```go
package main

import (
	"bytes"
	"fmt"
	"io"
	"net/http"
	"os"
	"time"
)

func main() {
	body := bytes.NewBufferString(`{"number":42467101}`)
	req, err := http.NewRequest(http.MethodPost, "https://api.binlookupapi.com/v1/bin", body)
	if err != nil {
		panic(err)
	}
	req.Header.Set("Authorization", "Bearer "+os.Getenv("BINLOOKUP_API_KEY"))
	req.Header.Set("Content-Type", "application/json")

	client := &http.Client{Timeout: 30 * time.Second}
	resp, err := client.Do(req)
	if err != nil {
		panic(err)
	}
	defer resp.Body.Close()

	payload, _ := io.ReadAll(resp.Body)
	switch resp.StatusCode {
	case 200:
		fmt.Println(string(payload))
		fmt.Println(resp.Header.Get("X-Quota-Remaining"))
	case 401:
		fmt.Fprintln(os.Stderr, "The API key is missing or not valid.")
	case 403:
		fmt.Fprintln(os.Stderr, string(payload))
	case 404:
		fmt.Fprintln(os.Stderr, "The BIN is not in the data.")
	case 429:
		fmt.Fprintln(os.Stderr, "The daily quota is used.")
	case 400:
		fmt.Fprintln(os.Stderr, string(payload))
	default:
		fmt.Fprintf(os.Stderr, "The API returned HTTP %d.\n", resp.StatusCode)
	}
}
```

The success JSON has `mode` and `data`. The fields are in the [API reference](/docs/api-reference/#response-fields). On BLAPI-150KPM and above, the body also contains `meta.longer_bin_available`.

HTTP 403 is `FORBIDDEN` or `FEATURE_NOT_AVAILABLE`. Read the `error` field.

## Look up many BINs

`POST /v1/bins` accepts 1 to 2,000 values. It requires BLAPI-500KPM, or a test-mode organisation. Each value uses one lookup.

```go
client := &http.Client{Timeout: 60 * time.Second}
body := bytes.NewBufferString(`{"numbers":[400062,"400597",99999999]}`)
req, err := http.NewRequest(http.MethodPost, "https://api.binlookupapi.com/v1/bins", body)
if err != nil {
	panic(err)
}
req.Header.Set("Authorization", "Bearer "+os.Getenv("BINLOOKUP_API_KEY"))
req.Header.Set("Content-Type", "application/json")

resp, err := client.Do(req)
if err != nil {
	panic(err)
}
defer resp.Body.Close()
payload, _ := io.ReadAll(resp.Body)

if resp.StatusCode == 403 && bytes.Contains(payload, []byte("FEATURE_NOT_AVAILABLE")) {
	fmt.Fprintln(os.Stderr, "Batch lookup needs the BLAPI-500KPM plan.")
	return
}
if resp.StatusCode == 200 {
	fmt.Println(string(payload))
}
```

The `results` array keeps your order. See [Batch lookups](/docs/batch-lookups/). A batch that does not fit in the remaining quota returns 429 and uses no quota.

## Related pages

- [C# guide](/docs/guides/csharp/)
- [curl guide](/docs/guides/curl/)
- [API reference](/docs/api-reference/)
- [API keys](/docs/api-keys/)
- [Billing](/docs/subscriptions/)