Phone number verification for Handshake AI

To keep Handshake AI a secure and trustworthy platform for fellows and frontier AI labs, phone number verification is required during sign-up for all accounts. This applies to both the web and mobile app.

How the verification process works

When creating your Handshake AI account, you'll be prompted to verify your email address first. After that, you'll be asked to enter your mobile phone number through our partner Twilio. The country code will be pre-selected based on your location.

The following message will be displayed: "We'll send a one-time code to your phone. This helps us verify your identity and keep our community safe."

Note: Not all country codes are supported at this time. You must be able to verify a phone number with a supported country code to access Handshake. Standard messaging and data rates may apply.

Step 1: Enter your mobile number 

Enter your phone number when prompted. During this step, you'll also see two optional SMS preferences you can choose to enable. These are entirely separate from the verification message itself. Your number will not be used for these messages unless you've explicitly opted in.

Project and task updates (informational messages) If you opt into this, you'll receive text messages with updates about projects and tasks you're already active on - things like task availability changes, project status updates, and other time-sensitive information related to your current work.

Future project and task opportunities (promotional messages) If you opt into this, you'll receive text messages about new projects and opportunities you may be eligible for - including project launches, new matches, and relevant program announcements.

Note: You can opt into one, both, or neither. Your choices here won't affect your ability to participate in Handshake AI.

Once entered and op-in preferences are selected, click Verify with SMS. 

Step 2: Receive a verification code 

A one-time verification code will be sent to your phone via SMS through our partner Twilio. If you don't receive it right away, wait a bit because it may be delayed.

Step 3: Enter the code 

Type the code into the verification screen to complete the process.

Once verified, your number is securely stored and used only to confirm your identity and prevent misuse. It will not be visible to employers or other users.

Additional information

• Unsupported numbers: If your number can’t be verified (e.g., VoIP or toll-free numbers), you’ll be prompted to try again with a valid mobile number.
• Accounts created before verification was required: If your account was created before phone verification became mandatory and you're not affiliated with a school, you'll be asked to verify your number the next time you log in.
• Changing or updating phone number: Phone numbers cannot be edited, even by Handshake admins
• Phone number is associated with another account: This means your phone number is already linked to an existing account, potentially under a different email address. Try signing in through the Handshake AI login page using any email addresses that may have been used to create a Handshake account, including current or former school (.edu) email addresses. If you're unable to identify which account your phone number is linked to, contact Support for further investigation and provide the phone number you're attempting to use.

Troubleshooting tips

Didn't receive a verification code?

This is usually caused by rate limiting, carrier filtering, or blocked messages. Try the following:

• Wait 30 minutes before requesting another code. Requesting multiple codes in a short period can temporarily pause code delivery as a security measure. After 30 minutes, request a new code only once. Keep in mind that codes can arrive late. If a delayed code arrives, it may have already expired, so use the most recent code you receive.
• Make sure your phone can receive SMS messages from U.S. numbers. Verification codes are sent from a U.S. phone number. Some carriers and prepaid plans block international SMS by default, so confirm that international SMS is enabled with your carrier.
• Check for blocked numbers or spam filtering.
  • Android: Open the Messages app → tap the three-dot menu → Spam & blocked → unblock any unfamiliar numbers.
  • iPhone: Go to Settings → Apps → Messages → Blocked Contacts, and check your Unknown Senders or Junk messages if applicable.
• Check your Focus or Do Not Disturb settings. Make sure notifications or messages aren't being silenced.
• If you're in India, verify with your carrier that your phone number is not registered for Do Not Disturb (DND) services, which can block automated messages.
• Use a standard mobile number. Virtual or VoIP numbers (such as Google Voice or TextNow) often cannot receive verification codes.
• Perform a few quick device checks. Confirm that you entered the correct phone number and country code, ensure you have cellular service, and try toggling Airplane Mode on and off or restarting your phone.

Entered the code, but it didn't work? Verification codes expire after a limited time. If your code has expired, request a new one and enter the most recent code you receive.

Receiving an "Unsupported number" error? Try registering with a different mobile phone number.

Receiving the message, "We're unable to use this phone number. If you've previously registered, try signing in"? This message means the phone number is already associated with an existing Handshake account.

• If you've used Handshake before, try signing in to your existing account ai.joinhandshake.com/login.
• If you don't recognize the account associated with your phone number, contact Support and provide the phone number so we can investigate.
• If you're a student at a Handshake partner school, create your account using your school-issued .edu email address to connect directly with your institution.

Updating your SMS preferences

If you'd like to change your SMS preferences after completing verification, you can do so at any time through your account settings. You can also reply STOP to any SMS message to opt out of that message type.

For details on managing your notification preferences, refer to Managing Your Notification Preferences.