Email Authentication

Our Demo Embedded Wallet application serves an example of how email auth functionality might be integrated. We encourage you to try it (and check out the code) before diving into your own implementation.

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Prerequisites

Make sure you have set up your primary Turnkey organization with at least one API user that can programmatically initiate email auth on behalf of suborgs. Check out our Quickstart guide if you need help getting started. To allow an API user to initiate email auth, you’ll need the following policy in your main organization:

{
  "effect": "EFFECT_ALLOW",
  "consensus": "approvers.any(user, user.id == '<YOUR_API_USER_ID>')",
  "condition": "activity.resource == 'AUTH' && activity.action == 'CREATE'"
}

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Helper packages

• We have released open-source code to create target encryption keys, decrypt auth credentials, and sign Turnkey activities. We’ve deployed this as a static HTML page hosted on auth.turnkey.com meant to be embedded as an iframe element (see the code here). This ensures the auth credentials are encrypted to keys that your organization doesn’t have access to (because they live in the iframe, on a separate domain)
• We have also built a package to help you insert this iframe and interact with it in the context of email auth: @turnkey/iframe-stamper

In the rest of this guide we’ll assume you are using these helpers.

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Email Auth step-by-step

Here’s a diagram summarizing the email auth flow step-by-step (direct link):

Let’s review these steps in detail:

const iframeStamper = new IframeStamper({
iframeUrl: "https://auth.turnkey.com",
// Configure how the iframe element is inserted on the page
iframeContainerId: "your-container",
iframeElementId: "turnkey-iframe",
});

// Inserts the iframe in the DOM. This creates the new encryption target key
const publicKey = await iframeStamper.init();

window.localStorage.setItem("BUNDLE", bundle);

await iframeStamper.injectCredentialBundle(code);

   // New client instantiated with our iframe stamper
   const client = new TurnkeyClient(
   { baseUrl: "https://api.turnkey.com" },
   iframeStamper,
   );

   // Sign and submits the CREATE_WALLET activity
   const response = await client.createWallet({
   type: "ACTIVITY_TYPE_CREATE_WALLET",
   timestampMs: String(Date.now()),
   organizationId: authResponse.organizationId,
   parameters: {
      walletName: "Default Wallet",
      accounts: [
         {
         curve: "CURVE_SECP256K1",
         pathFormat: "PATH_FORMAT_BIP32",
         path: "m/44'/60'/0'/0/0",
         addressFormat: "ADDRESS_FORMAT_ETHEREUM",
         },
      ],
   },
   });

const code = window.localStorage.getItem("BUNDLE");
await iframeStamper.injectCredentialBundle(code);

const client = new TurnkeyClient(
{ baseUrl: "https://api.turnkey.com" },
iframeStamper,
);

// Sign and submits a SIGN_TRANSACTION activity
const response = await client.signTransaction({
type: "ACTIVITY_TYPE_SIGN_TRANSACTION_V2",
timestampMs: String(Date.now()),
organizationId: authResponse.organizationId,
parameters: {
   signWith: "0x...",
   type: "TRANSACTION_TYPE_ETHEREUM",
   unsignedTransaction: "unsigned-tx",
},
});

Congrats! You’ve succcessfully implemented Email Auth!

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Integration notes

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Email customization

We offer customization for the following:

• appName: the name of the application. This will be used in the email’s subject, e.g. Sign in to ${appName}
• logoUrl: a link to a PNG with a max width of 340px and max height of 124px
• magicLinkTemplate: a template for the URL to be used in the magic link button, e.g. https://dapp.xyz/%s. The auth bundle will be interpolated into the %s

// Sign and submits the EMAIL_AUTH activity
const response = await client.emailAuth({
  type: "ACTIVITY_TYPE_EMAIL_AUTH",
  timestampMs: String(Date.now()),
  organizationId: <sub-organization-id>,
  parameters: {
    email: <user-email>,
    targetPublicKey: <iframe-public-key>,
    apiKeyName: <optional-api-key-name>,
    expirationSeconds: <optional-api-key-expiration-in-seconds>,
    emailCustomization: {
      appName: <optional-your-app-name>,
      logoUrl: <optional-your-logo-png>,
      magicLinkTemplate: <optional-magic-link>
    }
  },
});

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Bespoke email templates

We also support custom HTML email templates for Enterprise clients on the Scale tier. This allows you to inject arbitrary data from a JSON string containing key-value pairs. In this case, the emailCustomization variable may look like:

...
emailCustomization: {
  templateId: <HTML-template-stored-in-turnkey>,
  templateVariables: "{\"username\": \"alice and bob\"}"
}
...

In this specific example, the value alice and bob can be interpolated into the email template using the key username. The use of such template variables is purely optional.

Here’s an example of a custom HTML email containing an email auth bundle:

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Custom email sender domain

Enterprise clients on the Scale tier or higher can also customize the email sender domain. To get set up, please reach out to your Turnkey rep to get started but here is what you’ll be able to configure:

message InitOtpAuthIntent {
  // Optional custom email address from which to send the OTP email
  optional string send_from_email_address = "notifs@mail.domain.com";

  // Optional custom sender name (e.g. "MyApp Notifications")
  optional string send_from_email_sender_name = "MyApp Notifications";

  // Optional reply-to email address
  optional string reply_to_email_address = "reply@mail.domain.com";
}

Please keep in mind that:

• Email has to be from a pre-whitelisted domain
• If there is no send_from_email_address or it’s invalid, the other two fields are ignored
• If send_from_email_sender_name is absent, it defaults to “Notifications” (again, ONLY if send_from_email_address is present and valid)
• If reply_to_email_address is absent, then there is no reply-to added. If it is present, it must ALSO be from a valid, whitelisted domain, but it doesn’t have to be the same email address as the send_from_email_address one (though once again, this first one MUST be present, or the other two feature are ignored)

If you are interested in implementing bespoke, fully-customized email templates and sender domain, please reach out to hello@turnkey.com.

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Credential validity checks

By default, if a Turnkey request is signed with an expired credential, the API will return a 401 error. If you’d like to validate an injected credential, you can specifically use the whoami endpoint:

const whoamiResponse = await client.getWhoami({
  organizationId,
});

A valid response indicates the credential is still live; otherwise, an error including unable to authenticate: api key expired will be thrown.