Yubigo is a Yubikey client API library that provides an easy way to integrate the Yubico Yubikey into your existing Go-based user authentication infrastructure.

// create a new yubiAuth instance with id and key
yubiAuth, err := yubigo.NewYubiAuth("1234", "fdsaffqaf4vrc2q3cds=")
if err != nil {
	// probably an invalid key was given
	log.Fatalln(err)
}

// verify an OTP string
result, ok, err := yubiAuth.Verify("ccccccbetgjevivbklihljgtbenbfrefccveiglnjfbc")
if err != nil {
	log.Fatalln(err)
}

if ok {
	// succes!! The OTP is valid!
	log.Printf("Used query was: %s\n", result.GetRequestQuery()) // this query string includes the url of the api-server that responded first.
} else {
	// fail! The OTP is invalid or has been used before.
	log.Println("The given OTP is invalid!!!")
}

yubigo.HTTPClient = &http.Client{
    Timeout: time.Second * 15,
    Transport: &http.Transport{
        MaxConnsPerHost:     20,
        MaxIdleConnsPerHost: 5,
        DialContext: (&net.Dialer{
            Timeout:   30 * time.Second,
            KeepAlive: 60 * time.Second,
        }).DialContext,
        TLSHandshakeTimeout:   10 * time.Second,
        ResponseHeaderTimeout: 10 * time.Second,
        ExpectContinueTimeout: 1 * time.Second,
    },
}

// Disable HTTPS cert verification. Use true to enable again.
yubiAuth.HttpsVerifyCertificate(false)

// Disable HTTPS. Use true to enable again.
yubiAuth.UseHttps(false)

// Set a list of n servers, each server as host + path. 
// Do not prepend with protocol
yubiAuth.SetApiServerList("api0.server.com/api/verify", "api1.server.com/api/verify", "otherserver.com/api/verify")