# Referrals
Referral codes are a core primitive of Spindl's referral program. Each wallet can create one unique code, that can be shared via the `ref` tag on URLs. Codes can be custom or random, depending on your ideal app experience.
For instance, a shareable link might look:
```
https://app.mydapp.xyz/trade?ref=kunal
^ referral code
```
The Spindl SDK will automatically capture `ref` URL parameters in Page View events to associate visits with Referrers.​
Referral codes can be created manually through the [Spindl Dashboard](https://app.spindl.xyz/referrals), or programmatically from your app with the Javascript SDK.​
###
### Get Referrer Code
This method can be used to see if a wallet already has a code associated with it.
**SDK Method**
```typescript
getReferrerCode(address: string): Promise
```
**Parameters**
* Address: The wallet address
**Returns**
A referral code if set​
###
### Create Referrer Code
**SDK Method**
```typescript
createReferrerCode(address: string, code?: string): Promise
```
**Parameters**
* Address: The wallet address
* Code: An optional custom referral code to use. If not set, we'll generate a random code
**Returns**
This will throw a 400 error if the code is invalid / in-use, or the wallet address already has a referral code
#### **​**
### **Validate Referrer Code**
This method can be used to quickly verify if a code is valid (it doesn't make network calls, so can be called on keystrokes / input changes efficiently)
**SDK Method**
```typescript
validateReferrerCode(code: string): boolean;
```
**Parameters**
* Code: A custom short code, to validate
**Returns**
Returns true if the code is valid.
### Check Referrer Code
This method can be used to see if a custom code is already in use.
**SDK Method**
```typescript
checkReferrerCode(code: string): Promise;
```
**Parameters**
* Code: A custom short code, to check if it is available
**Returns**
Returns true if the code is available, false if it is not valid or unavailable