nextauthjs/next-auth · error · TypeError

Provider id "${provider}" does not refer to a WebAuthn provi

Error message

Provider id "${provider}" does not refer to a WebAuthn provider.
Please use `import { signIn } from "@auth/sveltekit/client"` instead.

What it means

SvelteKit's non-client webauthn helper (lib/webauthn.ts signIn) validates that the requested provider id is exactly "webauthn" and throws a TypeError otherwise, telling developers to use the client entry point (@auth/sveltekit/client) instead. This module is for server-side WebAuthn flows; generic OAuth/email sign-ins are handled by the client signIn, so passing the wrong provider id here is a programming mistake the guard catches early.

Source

Thrown at packages/frameworks-sveltekit/src/lib/webauthn.ts:79

  authorizationParams?: SignInAuthorizationParams
): Promise<SignInResponse>
export async function signIn<Redirect extends boolean = true>(
  provider?: ProviderId,
  options?: SignInOptions<Redirect>,
  authorizationParams?: SignInAuthorizationParams
): Promise<SignInResponse | void> {
  const { callbackUrl, ...rest } = options ?? {}
  const {
    redirectTo = callbackUrl ?? window.location.href,
    redirect = true,
    ...signInParams
  } = rest

  const baseUrl = base ?? ""

  if (!provider || provider !== "webauthn") {
    // TODO: Add docs link with explanation
    throw new TypeError(
      [
        `Provider id "${provider}" does not refer to a WebAuthn provider.`,
        'Please use `import { signIn } from "@auth/sveltekit/client"` instead.',
      ].join("\n")
    )
  }

  const webAuthnBody: Record<string, unknown> = {}
  const webAuthnResponse = await webAuthnOptions(provider, signInParams)
  if (webAuthnResponse.error) {
    logger.error(new Error(await webAuthnResponse.error.text()))
    return
  }
  webAuthnBody.data = JSON.stringify(webAuthnResponse.data)
  webAuthnBody.action = webAuthnResponse.action

  const signInUrl = `${baseUrl}/callback/${provider}?${new URLSearchParams(authorizationParams)}`
  const res = await fetch(signInUrl, {

View on GitHub (pinned to a1a16a5a77)

Solutions

1. Pass the literal provider id "webauthn" to this server-side signIn.
2. If signing in with a non-passkey provider, import signIn from "@auth/sveltekit/client" instead.
3. Check your import: @auth/sveltekit/webauthn (server, passkeys only) vs @auth/sveltekit/client (browser, all providers).
4. Ensure the WebAuthn provider is registered in your auth config with id "webauthn".

Example fix

// before
import { signIn } from "@auth/sveltekit/webauthn"
await signIn("github") // TypeError
// after
import { signIn } from "@auth/sveltekit/client"
await signIn("github")
// or, for passkeys:
await signIn("webauthn")

if (provider !== "webauthn") {
  throw new TypeError("Server-side webauthn signIn only accepts provider id 'webauthn'; use @auth/sveltekit/client for other providers")
}

function isWebAuthnProvider(provider: string): provider is "webauthn" {
  return provider === "webauthn"
}

try {
  await signIn("webauthn", { /* action: 'register' | 'authenticate' */ })
} catch (err) {
  if (err instanceof TypeError && err.message.includes("does not refer to a WebAuthn provider")) {
    console.error("Wrong signIn module — import signIn from '@auth/sveltekit/client' for non-passkey providers")
  }
}

When it happens

Trigger: Calling the server-side signIn (from @auth/sveltekit/webauthn) with a provider id other than "webauthn" — e.g. passing "github", "credentials", an email provider id, or leaving the provider argument undefined — when the intent was to start a passkey sign-in.

Common situations: Developers migrating from the client signIn API import the wrong module and reuse existing provider ids; or they call the webauthn helper without arguments expecting it to default to passkeys; or copy-pasted sign-in code paths for OAuth flows.

Related errors

• Provider id "${provider}" does not refer to a WebAuthn provi
• Provider id "${provider}" refers to a WebAuthn provider. Ple
• Authenticator not found.
• Authenticator not found.
• Authenticator not found.

AI-assisted analysis of nextauthjs/next-auth@a1a16a5a77 (2026-08-28). Data as JSON: /api/errors/b75834f8c935bb95. Report an issue: GitHub.