# ei — the Google search parameter that carries a timestamp

- Canonical: https://linkclean.app/trackers/ei/
- Updated: 2026-10-01
- Author: Ken Tominaga (https://ken0nek.com)
- Get the app: https://apps.apple.com/us/app/linkclean/id6758604043

Parameter: `ei` · Category: Analytics IDs · Vendor: Google Search

> ei is **Google Search's session identifier**. It is undocumented, but people who decoded it found that it begins with a Unix timestamp — **the moment the search was run**. A results link you forward therefore says when you searched. LinkClean strips it on Google's search domains.

## What ei contains

The value looks like noise — `ei=AbCdZfGhI…` — but it is a Base64-encoded message, and the leading bytes decode to a Unix timestamp followed by other values nobody outside Google has explained. The timestamp is set when the results page is generated.

**Google publishes no specification for ei.** Everything here is observed behaviour or the work of people who decoded it, not a documented contract. The [Google search URL](https://linkclean.app/learn/google-search-url-parameters/) overview covers the rest of the session keys.

## Why a timestamp matters in a shared link

A search link with ei attached tells whoever receives it when you ran the search, to the second. Usually that is harmless. It stops being harmless when the time is the thing you would rather not share — a search made at 3 a.m., or weeks before you said you started looking into something.

The search itself does not need it. Take ei off and the same query runs fresh.

## Its companions

ei rarely travels alone. The same results URL usually carries [ved](https://linkclean.app/trackers/ved/) (which link was clicked), [sca_esv](https://linkclean.app/trackers/sca-esv/) (an unexplained token), and from Chrome's address bar [rlz](https://linkclean.app/trackers/rlz/) and [gs_lcrp](https://linkclean.app/trackers/gs-lcrp/). A related `sei` appears on some pages and is stripped by the same rule set.

## How LinkClean removes it

Default-on, and scoped to Google's search domains (`google.com` and the main country domains). The same letters on any other site are left alone, and `q=`, `tbm=`, `udm=` and `hl=` — the parts that decide what the search shows — are never touched.

The host scope matters more here than usual. `ei` is two letters, and on another site it could be anything. LinkClean only removes it where it is known to be Google's session identifier.

## Example

Looks like this in a URL: `https://www.google.com/search?q=link+cleaner&ei=AbCdZfGhI&sca_esv=5a1b2c3d4e5f6a7b&oq=link+clea`

After LinkClean: `https://www.google.com/search?q=link+cleaner`

## Frequently asked

**Does ei identify me personally?**

Not on what has been decoded. The known part is a timestamp; the rest is unexplained. It identifies a search session and when it started, which is still more than a shared link needs to say.

**Will the search still work without ei?**

Yes. The query is in q=. Google generates a new session identifier for whoever opens the cleaned link.

**Is there official documentation for ei?**

No. Google does not document it. The timestamp finding comes from independent analysis of the encoded value.

**Why is ei only removed on Google?**

Because a two-letter name is far too generic to strip everywhere. The rule applies on Google's search domains and nowhere else.


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