diff --git a/abstract-relay.ts b/abstract-relay.ts
index 8189993..5bc3c10 100644
--- a/abstract-relay.ts
+++ b/abstract-relay.ts
@@ -24,6 +24,9 @@ export class AbstractRelay {
   public onclose: (() => void) | null = null
   public onnotice: (msg: string) => void = msg => console.debug(`NOTICE from ${this.url}: ${msg}`)
 
+  // this is exposed just to help in ndk migration, shouldn't be relied upon
+  public _onauth: ((challenge: string) => void) | null = null
+
   public baseEoseTimeout: number = 4400
   public connectionTimeout: number = 4400
   public openSubs: Map<string, Subscription> = new Map()
@@ -215,6 +218,7 @@ export class AbstractRelay {
           return
         case 'AUTH': {
           this.challenge = data[1] as string
+          this._onauth?.(data[1] as string)
           return
         }
       }