> ## Documentation Index
> Fetch the complete documentation index at: https://help.equip.co/llms.txt
> Use this file to discover all available pages before exploring further.

# How Invitation Links Work

> Unique links, expiry, and what candidates see when a link is invalid.

<Tip>
  Every email invitation carries a **unique, one-time assessment link** tied to the invited email address. Only someone with access to that inbox can use it, links never expire unless you set an expiry, and re-clicking a link safely resumes an unfinished attempt.
</Tip>

## Unique Links per Candidate

When you send [email invitations](/email-invitations), every recipient gets the same email body. The only difference between the emails is the **assessment link**: each candidate receives a unique URL that only they can use.

Here is what happens when a candidate clicks their link.

<Steps>
  <Step title="Candidate opens the link">
    The link identifies which email address it was sent to. It works on any device and any supported browser.
  </Step>

  <Step title="Equip sends a verification code">
    A one-time code goes to the **invited email address**, not to whoever opened the link. See [Candidate Login Methods](/candidate-login-methods) for the full sign-in flow.
  </Step>

  <Step title="Candidate verifies and starts">
    After entering the code, the candidate is taken straight to the assessment. No password or account setup is needed.
  </Step>
</Steps>

<Note>
  Because the verification code always goes to the original invitee's inbox, **forwarding a link does not transfer the invitation**. If Candidate 1 shares their link with Candidate 2, the code still lands in Candidate 1's inbox, so Candidate 2 cannot proceed.
</Note>

The verification code is 6 digits and expires **30 minutes** after it is sent. If theirs expires, the candidate can simply request a new one from the same page.

### Switching devices

The link and the email address are bound together, so Equip recognizes the same candidate even on a different device. Clicking the link again resumes the attempt with the remaining time intact: a candidate who left a test with 10 minutes remaining continues with 10 minutes on the new device.

This also means a fresh invitation cannot grant a second attempt. If a candidate has an unfinished attempt, any new link you send them resumes that same attempt. See [Candidate Re-Attempts](/candidate-reattempts) for how to allow a genuine retake.

## Link Expiry

By default, invitation links **never expire**. You control expiry per batch of invitations with the **Link Expiry (days)** field on the **Send Invitations** tab.

| Link Expiry (days) value | Behavior                                        |
| ------------------------ | ----------------------------------------------- |
| Empty (default)          | Links never expire                              |
| 1 to 365                 | Links stop working that many days after sending |

<Tip>
  Setting an expiry is a simple way to keep your pipeline moving: candidates see a real deadline, and stale invitations stop being usable on their own. If you instead need to control the exact start window, use the **Cannot Start Before** and **Cannot Start After** [assessment settings](/assessment-settings).
</Tip>

## Invalid and Already-Used Links

A link can stop working for a few different reasons. In each case the candidate sees a specific explanatory page rather than a generic error, so they know what happened and what to do next.

| Situation                        | What the candidate sees                                                       |
| -------------------------------- | ----------------------------------------------------------------------------- |
| Link expired                     | An error page explaining the link is no longer valid                          |
| Credit reclaimed                 | The link is invalidated and no longer opens the assessment                    |
| Attempt deleted by the recruiter | An error page; the candidate needs a fresh invitation                         |
| Assessment already completed     | The completion screen, not the tests again                                    |
| Someone else opens the link      | The verification code still goes to the invited email, so they cannot proceed |

A few details worth knowing:

* **Clicking a link multiple times is safe.** A candidate who has not started can open their link any number of times until it expires. A candidate mid-attempt resumes where the rules allow. A finished candidate just sees the completion screen.
* **Revoking an invitation** only happens as a side effect of [reclaiming the credit](/reclaim-credits). Reclaiming invalidates the candidate's link and deletes any test data tied to it.
* **Re-inviting is safe too.** If a candidate says they never received or lost their link, check its [email status](/email-status) first, then re-invite if needed. The unused link's credit is reclaimable after 24 hours as long as the candidate never started.

<Warning>
  Reclaiming a credit is destructive: it revokes the candidate's link and permanently deletes their test data, including any points earned. Only reclaim when you are sure the candidate should not, or will not, attempt the assessment.
</Warning>

## Related Resources

* [Email Invitations](/email-invitations) - How to send invitations, upload recipients, and set link expiry
* [Share URL vs Email Invitations](/share-url-vs-email) - When to use unique links versus a public assessment URL
* [Candidate Re-Attempts](/candidate-reattempts) - Why new links resume old attempts and how to allow retakes
* [Email Status](/email-status) - Track whether invitations were delivered, opened, and clicked