# Structured Headers Hard Mode

> This addon injects 2 HTTP headers into every request (sec-hardmode-list and sec-hardmode-dict) which make use of Structured Header syntax.

Canonical page: [https://chrome-stats.com/d/structured-headers-hard-mode](https://chrome-stats.com/d/structured-headers-hard-mode)

## Overview

- **ID:** `structured-headers-hard-mode`
- **Platform:** Firefox
- **Type:** Firefox add-on
- **Status:** Available
- **Publisher:** Mike Taylor
- **Category:** web-development
- **Daily users:** 1
- **Version:** 1.0.0
- **Last updated:** 2020-11-27
- **First published:** 2020-11-27
- **Size:** 12 KB
- **Data as of:** 2026-09-08
- **Store listing:** [Firefox Add-ons Store](https://addons.mozilla.org/firefox/addon/structured-headers-hard-mode/)
- **Website:** [https://github.com/miketaylr/structured-headers-hardmode](https://github.com/miketaylr/structured-headers-hardmode)

## Description

Structured Headers Hard Mode is a Firefox add-on that injects structured headers into every request. Its goal is to identify servers that are unable to handle Structured Header syntax and notify them. Please note that this add-on may break things and can be disabled or enabled by clicking on the icon. Report any broken sites or services on GitHub.

## Rankings

- #116,193 — Overall
- #24 — modheader

## Permissions and access

### Permissions

- `webRequest`
- `webRequestBlocking`
- `<all_urls>`

## Safety

- **Risk impact:** Moderate risk impact
- **Risk likelihood:** Moderate risk likelihood

### Analysis details

- Allows access to all websites, posing a significant security risk as it can monitor and modify data from any visited site.
- This extension has low user count. Unpopular extensions may not be stable or safe.

> Some risk analysis details are omitted from this free response. [Upgrade to view the full analysis](https://chrome-stats.com/pricing).

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Source: [Chrome-Stats](https://chrome-stats.com/d/structured-headers-hard-mode)