This is for:


In this article, we’ll introduce you to Jolt, what it’s used for, and its associated technical details.

What is Jolt?

Jolt is a lightweight library, deployed as an extension to smartserve.js, that listens for and sends all QProtocol events emitted on your website to Qubit’s Data Store. During the send, Jolt enriches each event with meta and context data.

You can read more about this in Event Enrichment.

Refer to the following examples and tables:

Example JavaScript for meta data

meta: {
  url: '',
  trackingId: 'myproperty',
  batchTs: 1522310723801,
  type: 'myproperty.trView',
  source: 'jolt@7.41.0',
  id: 'cyeh53umxgg-0jfc8i02i-m0aw3v4',
  bundleId: '2018-03-28T14:06:37@5b4d044@release-2018-03-19T10:00:00Z@2018-03-29T05:38:25',
  seq: 6,
  ts: 1522310723801

Schema for meta data

Field (JS Data Type) Description

url (String)

The current page URL the event was emitted from

trackingId (String)

The tracking Id for your property

batchTs (Number)

The timestamp for when the batch of events was sent to Qubit

type (String)

The event type that was enriched by Jolt

source (String)

The version of Jolt deployed on your site

id (String)

Random Id for the emitted event

bundleId (String)

The version and build of Smartserve

seq (Number)

A sequence that reports the number of events emitted by the visitor globally by device and site

ts (Number)

The client-side timestamp for when the event was emitted - will always be less than batchTs

Example Javascript for context data

context: {
  viewTs: 1522310723801,
  sessionViewNumber: 2,
  entranceViewNumber: 2,
  lifetimeValue: {
    value: 0
  sample: '77542',
  timezoneOffset: -60,
  viewNumber: 2,
  sessionTs: 1522310705008,
  entranceTs: 1522310705008,
  conversionCycleNumber: 1,
  id: '8lt0vannbw8-0jfc8hl8v-xj2r3pc',
  sessionNumber: 1,
  entranceNumber: 1,
  conversionNumber: 0

Schema for context data

Field (JS Data Type) Description

viewTs (Number)

A timestamp for the most recent view event

sessionViewNumber (Number)

The view number within the current session. A session is defined as any sequence of view events with less than 30 minutes between each view

entranceViewNumber (Number)

The view number within the current entrance. An entrance is defined as any sequence of view events where the first page comes from an external link, entered URL, or bookmark and where all subsequent pageviews are triggered by a selection within the site

lifetimeValue.value (Number)

The total amount transacted by the visitor over their lifetime - updated at the beginning of the next session

lifetimeValue.currency (String)

The ISO 4217 currency code for the user (for example, GBP, USD)

sample (String)

A randomly generated hash of the context Id used for sampling

timezoneOffset (Number)

The timezone offset of the visitor in minutes from UTC

viewNumber (Number)

The number of view events across the user’s lifetime

sessionTs (Number)

Timestamp for when the session was initiated

entranceTs (Number)

Timestamp for when the entrance was initiated

conversionCycleNumber (Number)

The number of conversion cycles the visitor has had across their lifetime. The conversionCycleNumber increments only on the session following a session with one or more conversions

id (String)

Equivalent of visitor Id and cookie Id that is randomly assigned to each visitor to identify them on your site - device specific

sessionNumber (Number)

The number of sessions the visitor has had across their lifetime

entranceNumber (Number)

The number of entrances the visitor has had across their lifetime

conversionNumber (Number)

The number of conversions the visitor has made during their lifetime - updated on the next view event after a conversion

Technical details

  • The library has a size of 23 kb

  • Jolt sends events asynchronously, so will not affect the end-user experience

  • Events that are emitted in a timespan of 500ms will be batched together into one request

  • All event data is compressed with Pako to ensure that the request payload is as small as possible

  • Compression allows a decrease of up to 95% in size for significant proportion of events

  • There is a maximum of 15 events that can be batched into one request. This ensures there are no site lock ups. When exceeding this limit, events are split into multiple requests


If Jolt is enabled on your site, a lookup request is made per visitor session to Qubit’s Data Store. This is to ensure that all the important visitor information is available in the browser. The URL of that request is

Data inspection

To get a view of the data sent, call in a console window.