---
title: "Start Time Travel"
description: "Test businesses, all-mode key only."
canonical_url: "https://twominutebilling.com/help/developers/api-reference/businesses/start-time-travel"
---
# Start Time Travel

> Test businesses, all-mode key only.

<api-operation method="POST" path="/v1/businesses/{biz}/time_travel/start">
<template v-slot:docs="">

## Path parameters

<table>
<thead>
  <tr>
    <th>
      Parameter
    </th>
    
    <th>
      Type
    </th>
    
    <th>
      Required
    </th>
    
    <th>
      Description
    </th>
  </tr>
</thead>

<tbody>
  <tr>
    <td>
      <code>
        biz
      </code>
    </td>
    
    <td>
      <code>
        string
      </code>
    </td>
    
    <td>
      <strong>
        yes
      </strong>
    </td>
    
    <td>
      Business id (biz_…)
    </td>
  </tr>
</tbody>
</table>

## Headers

<table>
<thead>
  <tr>
    <th>
      Parameter
    </th>
    
    <th>
      Type
    </th>
    
    <th>
      Required
    </th>
    
    <th>
      Description
    </th>
  </tr>
</thead>

<tbody>
  <tr>
    <td>
      <code>
        Idempotency-Key
      </code>
    </td>
    
    <td>
      <code>
        string
      </code>
    </td>
    
    <td>
      no
    </td>
    
    <td>
      Safely retry writes — repeats return the original response. If a write FAILED after it had already taken effect, that failure is what repeats: the key is spent, and a new attempt needs a new key.
    </td>
  </tr>
</tbody>
</table>

## Body

The request body is **required**.

<table>
<thead>
  <tr>
    <th>
      Field
    </th>
    
    <th>
      Type
    </th>
    
    <th>
      Required
    </th>
    
    <th>
      Description
    </th>
  </tr>
</thead>

<tbody>
  <tr>
    <td>
      <code>
        genesis_time
      </code>
    </td>
    
    <td>
      <code>
        string · ISO-8601
      </code>
    </td>
    
    <td>
      <strong>
        yes
      </strong>
    </td>
    
    <td>
      The time the simulated clock starts at (ISO-8601 UTC).
    </td>
  </tr>
</tbody>
</table>

## Status codes

<table>
<thead>
  <tr>
    <th>
      Status
    </th>
    
    <th>
      Meaning
    </th>
  </tr>
</thead>

<tbody>
  <tr>
    <td>
      <code>
        201
      </code>
    </td>
    
    <td>
      Time Travel state
    </td>
  </tr>
  
  <tr>
    <td>
      <code>
        400
      </code>
    </td>
    
    <td>
      Invalid body / not a test business
    </td>
  </tr>
  
  <tr>
    <td>
      <code>
        403
      </code>
    </td>
    
    <td>
      Requires an all-mode API key
    </td>
  </tr>
  
  <tr>
    <td>
      <code>
        409
      </code>
    </td>
    
    <td>
      Idempotency-Key conflict — the key is already in flight, or was reused with a different request payload.
    </td>
  </tr>
</tbody>
</table>
</template>

<template v-slot:request="">

```bash [Request]
curl -X POST "$TMBILLING_URL/v1/businesses/biz_XXXXXXXXXXXX01/time_travel/start" \
  -H "Authorization: Bearer $TMBILLING_API_KEY" \
  -H "Idempotency-Key: $(uuidgen)" \
  -H "Content-Type: application/json" \
  -d '{
    "genesis_time": "2026-03-14T09:30:00Z"
  }'
```

</template>

<template v-slot:response="">
<code-group>

```json [201 Created]
{}
```

```json [400 Bad Request]
{
  "error": {
    "type": "invalid_request_error",
    "message": "Invalid body / not a test business"
  }
}
```

```json [403 Forbidden]
{
  "error": {
    "type": "permission_error",
    "message": "Requires an all-mode API key"
  }
}
```

```json [409 Conflict]
{
  "error": {
    "type": "idempotency_error",
    "message": "Idempotency-Key conflict — the key is already in flight, or was reused with a different request payload."
  }
}
```

</code-group>
</template>
</api-operation>


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