# OpenLink Structured Data Sniffer

> Adds structured data discovery and handling of multiple content-types to your browser. Reveals Structured Metadata embedded within HTML pages in notations including POSH (Plain Old Semantic HTML), Microdata, JSON-LD, RDF-Turtle, and RDFa.

Canonical page: [https://chrome-stats.com/d/openlink-structured-data-sniff](https://chrome-stats.com/d/openlink-structured-data-sniff)

## Overview

- **ID:** `openlink-structured-data-sniff`
- **Platform:** Firefox
- **Type:** Firefox add-on
- **Status:** Available
- **Publisher:** OpenLink Software Inc
- **Category:** search-tools,social-communication
- **Daily users:** 346
- **Weekly downloads:** 4
- **Rating:** 4.36 / 5 (11 ratings)
- **Version:** 3.4.27
- **Last updated:** 2025-08-16
- **First published:** 2015-12-20
- **Size:** 2.41 MB
- **Data as of:** 2026-09-09
- **Store listing:** [Firefox Add-ons Store](https://addons.mozilla.org/firefox/addon/openlink-structured-data-sniff/)
- **Website:** [http://support.openlinksw.com/](http://support.openlinksw.com/)

## Description

OpenLink Structured Data Sniffer is a powerful browser extension that enhances the discovery and handling of structured metadata embedded within HTML pages and various content types. It supports multiple notations including POSH (Plain Old Semantic HTML), Microdata, JSON-LD, RDF-Turtle, and RDFa. Beyond simple discovery, the extension enables your browser to natively render JSON-LD and RDF-Turtle documents, offering seamless interaction with structured data.

Additional features include a comprehensive Web Service Console that facilitates RESTful interactions and identity toggling over TLS connections without browser restarts. Users can easily export data between formats like RDF-Turtle and JSON-LD via a convenient copy and paste function. Support for CSV and JSON documents enhances data visualization capabilities, while one-click saving of structured data to SPARQL-accessible Knowledge Graphs allows efficient data management. The extension also offers SuperLinks which connect words and phrases directly to entity descriptions across Knowledge Graphs, simplifying data exploration with a single click.

## Rankings

- #6,189 — Overall
- #19 — data
- #43 — x data
- #45 — handle
- #51 — picture
- #97 — openvpn

## Permissions and access

### Permissions

- `storage`
- `webRequest`
- `contextMenus`
- `scripting`
- `declarativeNetRequest`

### Host permissions

- `<all_urls>`

### Content script matches

- ``
- `*`
- `openlinksoftware.github.io`

## Safety

- **Risk impact:** High 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/openlink-structured-data-sniff)