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Glarity

Glarity is a free, ad-free browser extension for Chrome, Edge, Firefox, Opera and Safari that summarizes YouTube videos, web pages, PDFs, Google results and Gmail threads, and translates pages side by side using GPT-4o, Claude 3.5 or Gemini.

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Overview

What is Glarity?

Glarity is a browser extension that bills itself as a cross-language reading and writing assistant, or your AI copilot. Its core is open source, published on GitHub as sparticleinc/chatgpt-google-summary-extension, and the company behind it is Felo Incorporated in Tokyo, part of the Sparticle group founded in July 2019. The glarity.app domain was registered on 10/02/2023, and the first Wayback capture carrying real content dates from 03/03/2023.

The home page organizes the product around five pillars: Summary, Immersive translate, AI Reader, AI writer and AI Chat. In practice, the extension adds a summary panel next to a YouTube video, condenses any web page, Google results page, Twitter thread or PDF, mirrors a page in a second language side by side, helps draft replies in Gmail and opens a multi-model chat. The publisher advertises "Trusted by 1,000,000+ users" across its product pages and announces video summaries in over a dozen languages.

Three operating modes appear in the changelog: a Glarity mode with an included quota, a ChatGPT mode, and a mode where you supply your own OpenAI key with a temperature setting. The models cited are ChatGPT and GPT-4o, Claude 3.5, Gemini 1.5 Pro and Llama 3, while AI Chat announces 10+ models and a 200k context window.

Installation goes through the Chrome Web Store, whose package also covers Edge and Opera, through addons.mozilla.org for Firefox, and through the App Store for Safari. The free tier is permanent rather than a trial: 20,000 tokens a day and no GPT-4 requests. Paid plans start at 10 USD a month for Standard (2 million tokens, 150 GPT-4 requests), then Pro at 14.99 USD and Plus at 49.99 USD; billed yearly, the same plans cost 89, 149 and 179 USD.

Two surfaces exist outside the extension: an online YouTube summarizer that needs no installation, and askai.glarity.app, a public library of shared questions and answers. A single public API endpoint is documented, GET /api/youtube, an unauthenticated ChatGPT-plugin call returning a video transcript rather than a product API. The community lives on Discord and X; no LinkedIn or Instagram account is published.

What it does

  • Summarize a YouTube video and jump straight to timestamped key moments
  • Summarize any web page, news article, Google results page or Twitter thread
  • Summarize a PDF and chat with it, up to around 300 pages on a paid plan
  • Translate a whole page side by side, or just a text selection, images included
  • Generate a video transcript, then generate and translate its subtitles
  • Ask questions about a page or a video, or run a custom prompt to extract one specific detail
  • Draft and improve emails, articles and social replies, and chat with 10+ models
Audience

When to use Glarity / When not to

A quick filter to help you decide if Glarity is the right fit.

When to use Glarity

  • Readers who work across languages: a summary can come out in a language other than the one the page is written in, and full pages and PDFs can be mirrored side by side with their translation.
  • Students and researchers: the Chat PDF surface is aimed explicitly at students, researchers and professionals, and covers books, research papers, manuals and legal contracts.
  • Heavy YouTube viewers who want a written summary, timestamped key moments, a transcript and a question-and-answer session on a video instead of watching it end to end.
  • Desk research and monitoring: any web page, news article, Google results page or Twitter thread can be condensed, custom prompts can pull one specific detail out of a page, and assisted replies can be drafted straight inside Gmail.
  • Cost-conscious users and multi-model tinkerers: the free tier is permanent at 20,000 tokens a day, some PDF routes need no account at all, and AI Chat advertises 10+ models and a 200k context window behind a single subscription instead of several.

When not to use Glarity

  • Teams that need a data processing agreement, a named list of sub-processors or a security certification such as SOC 2 or ISO 27001: none of these is published anywhere on the site.
  • Organizations bound by data-residency rules: no hosting country and no hosting region is stated, in the privacy policy or anywhere else.
  • Users who require a documented training opt-out: the terms and the privacy policy say nothing at all about model training, so there is no commitment and no opt-out mechanism either way.
  • Native Android users: there is no Play Store application, even though the Japanese legal notice lists Android 10 or above among the supported environments.
  • Developers looking for a product API: the only public interface is a single unauthenticated endpoint, GET /api/youtube, which returns a YouTube transcript for a ChatGPT plugin.
Get started

How to use Glarity

A typical end-to-end flow, from setup to results.

  1. Install the extension from the Chrome Web Store, whose package also covers Edge and Opera, from addons.mozilla.org for Firefox, or from the App Store for Safari.
  2. Open a YouTube video: the summary panel appears next to the player, with timestamped key moments.
  3. On any web page, right-click and choose the toggle translate page option to display the original and its translation side by side.
  4. Select text on a page to translate it on the spot or send it to the Chat tab.
  5. Open a PDF in the browser to summarize it or ask questions about it; the Chat PDF route needs no registration.
  6. Use the keyboard shortcut to open the Copilot sidebar and trigger the automatic summary of the current page.
  7. Write a custom prompt when you need one precise piece of information rather than a general summary.
  8. Optionally create an account, or enter your own OpenAI key and set the temperature yourself.
  9. Enter a promotional code, if you have one, on the Redeem page of your account.
  10. Cancel a paid plan on your own from the settings of your personal account.
Quick read

Pros & Cons

Pros

  • A permanent free tier rather than a trial: 20,000 tokens a day, reset daily, and some routes such as PDF summarizing work without an account.
  • Broad browser coverage: Chrome, Edge, Firefox, Opera, and Safari through the App Store.
  • Several front-line models behind a single subscription, GPT-4o, Claude 3.5, Gemini 1.5 Pro and Llama 3, with the option of plugging in your own OpenAI key.
  • Low paid entry point at 10 USD a month, or 89 USD a year on the Standard plan.
  • Cross-language summarizing: the summary can be produced in a language other than the one of the source page.
  • An open-source core anyone can inspect on GitHub, and a product that carries no advertising and says so explicitly.
  • A refund without justification within 7 days of the start of service, self-service cancellation from the account settings, and an unusually complete Japanese legal notice: registered name, postal address, telephone with opening hours and a named person responsible for operations.

Cons

  • The public pricing grid renders no amount at all in static HTML, returning No data: the figures only exist behind a JavaScript call to the site's own product API, so a buyer cannot read them from the page source.
  • No data processing agreement, no sub-processor list, no hosting country or region, and no certification such as SOC 2 or ISO 27001.
  • Nothing is said about training models on user content, and no opt-out is documented.
  • The terms of use and the privacy policy share one page and one effective date, 04.07.2023, never revised since, and the text is visibly derived from OpenAI's: it refers to API keys, Service Terms and Usage Policies that do not exist on this site.
  • The public changelog stops at version 4.25.3 dated 25/06/2024, while the blog is still publishing in August 2026.
  • No Android application, even though the legal notice lists Android 10 or above as a supported environment, and no LinkedIn, Instagram or YouTube presence is published.
  • Loose brand identity and thin support paths: Felo Inc. in the footer, Felo Incorporated in the legal notice and Sparticle Inc. at the bottom of askai.glarity.app, support addresses hosted on other domains (felo.ai, sparticle.com), no contact page and no ticketing system, a dead anchor behind the marketing Log in link, and a sitemap declared in robots.txt that returns a 404.
Pricing

Pricing & Plans

Glarity offers a permanent free plan, Glarity Basic, capped at 20,000 tokens per day with no GPT-4 requests and a daily reset. The lowest paid entry point is the Standard plan at 10.00 USD per month, or 89 USD per year; Pro costs 14.99 USD per month or 149 USD per year, and Plus 49.99 USD per month or 179 USD per year. Other currencies are published by the site's own product API, notably JPY 1,500, 1,998 and 6,998 per month, and CNY 70, 99 and 349. The Japanese legal notice states that the price varies from JPY2,198 depending on the plan, with no additional costs. Payment is by credit card according to that notice, and the plan FAQ adds Google Pay, Apple Pay, Link, Alipay and WeChat Pay. A refund may be obtained without justification within 7 days of the start of service, although section 4(a) of the terms otherwise states the principle of non-refundable payments; section 4(c) provides that a price increase takes effect 14 days after the notice is published. These amounts come from the publisher's first-party API rather than from the pricing page, which displays none of them in its HTML.

Glarity Basic
  • free and permanent
  • 20
  • 000 tokens per day with no GPT-4 request
  • quota reset daily.
Glarity Pro
  • 14.99 USD per month or 149 USD per year
  • 5
  • 000
  • 000 tokens per month and 600 GPT-4 requests per month.
Glarity Plus
  • 49.99 USD per month or 179 USD per year
  • unlimited tokens and unlimited GPT-4 requests
  • with at least 600 GPT-4 requests guaranteed each month and speed or quality possibly dropping beyond that
  • the plan is described as still being in its testing phase.
Prices and plans listed above may evolve. Always check the official pricing page before subscribing.
Trust & Privacy

Data, GDPR & hosting

A consolidated view of how Glarity handles your data.

GDPR overview

The site never claims GDPR compliance: the word GDPR does not appear anywhere, and compliance is not denied either. What section 4 of the privacy policy does offer is a list of GDPR-style rights for people in the EEA, the UK and across the globe: access, deletion, correction, portability, restriction, withdrawal of consent, objection and complaint to a local supervisory authority. Rights are exercised through the Glarity account or by emailing support@felo.ai, and the publisher may verify your identity first. A named privacy contact is given, Tatsuya Kanada, at the Tokyo address. Against that: no Article 27 EU representative, no DPO named as such, no DPA, no sub-processor list, no certification. Section 5(c) of the terms pushes notice and consent duties onto users who process personal data through the service, and section 8 applies Japanese law and Tokyo courts. Both documents are dated 04.07.2023.

Who owns the data?

Section 3(a) of the terms groups your inputs and the outputs generated from them under a single label, Content. As between the parties and as far as the applicable law allows, you own all Input, and you stay responsible for that Content, including its lawfulness. The publisher states that it may use Content to provide and maintain the service, to comply with the law and to enforce its policies; nothing broader is claimed, and model training is never mentioned in either document. Feedback is treated separately: section 2(b) lets the publisher use any comment, idea or suggestion without restriction or compensation. Section 2(e) puts the burden of holding the rights over the source material you submit for summarizing on you.

Reuse rights

The privacy policy lists account data (name, contact details, credentials, payment card, transaction history), User Content (prompts, files, feedback), communication information and social information, plus technical data collected automatically: log data such as IP address, browser type and settings and timestamps, usage data, device information and cookies. Google Analytics is used, and the policy states that the data collected is shared with other Google services and may serve to personalize advertising across the Google network. The stated purposes are providing, administering, maintaining and analyzing the service, improving it and conducting research, communicating with users, developing new programs, preventing fraud, business transfers and legal obligations. Aggregated or de-identified data may be analyzed, shared with third parties or published, with an undertaking not to re-identify it except where the law requires. Disclosure is possible to vendors (hosting, cloud, IT, emailing, analytics), in a business transfer, to the authorities and to affiliated companies, and not one vendor is named. Whether any of this content feeds AI model training is not addressed at all: the documents neither allow it nor rule it out.

Data retention & training

Retention summary
The privacy policy sets no figures. Section 6 says personal information is kept only as long as needed to provide the service, or for other legitimate business purposes such as resolving disputes, safety and security, or complying with legal obligations, and that the period depends on the volume, nature and sensitivity of the data, the risk of unauthorized use, the purpose and any legal requirements. No retention period, no deletion deadline and no zero-retention commitment is given anywhere, and the inputs and outputs submitted to the AI have no separate retention rule. Deletion can be requested from the Glarity account or by emailing support@felo.ai, after identity verification (section 4). On termination, section 6(b) of the terms requires you to stop using the service and to return or destroy confidential information; sections 3 and 5 to 9 survive.
GDPR contact

Hosting summary

No hosting location is published. Neither the privacy policy nor the terms names a country or a region where data is stored, and the site has no trust or security page. Section 3 of the privacy policy says the publisher relies on hosting, cloud and IT service providers, but not one of them is named, so there is no sub-processor list to inspect. On security, section 6 promises commercially reasonable technical, administrative and organizational measures to protect personal information, without detail and without any certification such as SOC 2 or ISO 27001. What is known is the legal frame rather than the physical one: the publisher is Japanese and section 8 of the terms applies Japanese law with exclusive jurisdiction in Tokyo, which says nothing about where the data actually sits. The domain's IP address (104.21.32.145, Cloudflare AS13335, anycast) is a CDN front end and is no indication of hosting either. Anyone with a data-residency requirement should treat this point as unanswered.

Watch-outs

Things to keep in mind

Risks and trade-offs to weigh before adopting Glarity.

  • Summaries are AI-generated and the service is provided as is, with no accuracy warranty under section 7(b): treat every summary as a draft to be checked against the source, especially for legal or medical material.
  • The extension reads the content of the pages you browse, which is a broad window onto your navigation, and section 2(e) makes you the one who must hold the rights over whatever you submit for summarizing.
  • Neither the terms nor the privacy policy mentions model training: there is no non-training commitment and no opt-out, so genuinely sensitive documents are best kept out of the tool.
  • Leaning on summaries instead of reading can quietly erode your own reading and note-taking habits: the tool tells you what a page says, not what it leaves out or gets wrong.
  • Prices can change, with effect 14 days after the notice is published under section 4(c), and immediately for legal reasons or for Beta Services.
  • The account is reserved for individual use: automated activity or multi-user access may lead to suspension, and the Plus plan is presented as being in a testing phase that may evolve with OpenAI and Anthropic rules.
  • The product depends on third-party model providers, and the site's own notice administration page shows a past announcement about ChatGPT mode being suspended after a rules change; liability is capped by section 7(c) at the greater of the fees paid over 12 months or 100 USD.
Setup

Setup & Integrations

Technical difficulty

Very low. Installation is one click from your browser's store, with no server-side configuration and no technical skill required. Some routes work with no account at all: the Chat PDF page advertises no registration and free use. Day-to-day use runs on right-clicks, text selection and a keyboard shortcut for the sidebar. Advanced options are optional: creating an account, or supplying your own OpenAI key with a temperature setting. An online version avoids installation altogether. The legal notice lists iOS 13.0+, Windows 7+ and Android 10+ as supported environments, and the single public API endpoint needs no authentication.

Deployment

Browser extensionChrome extensionWeb appIOS appAPIPlugin

Apps stores

Integrations

YouTube Google Twitter Gmail Reddit Yahoo Wikipedia OpenAI ChatGPT Claude Gemini Llama

Supported languages

EnglishJapaneseKoreanTraditional ChineseSimplified Chinese
Company

Behind Glarity

Company name
Felo Incorporated
Founded
10/02/2023
Country of origin
🇯🇵 Japan
Headquarters
6-12, Nihonbashikodemmacho, Chuo-ku, Tokyo, Nihonbashi, Mori Building 3F
UBO
Tatsuya Kanada
UBO country
🇯🇵 Japan
Domain registrar country
🇺🇸 United States
Legal contact
Support contact
Official links

Resources

All the official URLs gathered for verification and reference.

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FAQ

Frequently asked questions

What does Glarity do?
It is a browser extension that summarizes YouTube videos, web pages, news articles, Google results pages, Twitter threads and PDFs, translates pages and text selections side by side, helps write emails and posts, and opens a chat with several AI models.
Which browsers and devices does it work on?
Chrome, Edge, Firefox, Opera and Safari. The Safari version is distributed through the App Store as an extension rather than a standalone application. There is no Play Store app, even though the Japanese legal notice lists Android 10 or above among the supported environments.
Is there a free plan?
Yes. Glarity Basic is free and permanent rather than a time-limited trial: 20,000 tokens per day, reset daily, with no GPT-4 request. Some routes, such as summarizing a PDF, work without creating an account.
How much does the first paid plan cost?
The Standard plan costs 10.00 USD per month, or 89 USD per year. Pro is 14.99 USD per month or 149 USD per year, and Plus 49.99 USD per month or 179 USD per year. Prices in yen, yuan, New Taiwan dollars and won are published as well.
What is the difference between the Standard, Pro and Plus plans?
According to the publisher's plan FAQ, "The main differences are the number of tokens and the usage limits of advanced models. There are no functional differences." Standard gives 2 million tokens and 150 GPT-4 requests a month, Pro 5 million tokens and 600 requests, and Plus unlimited tokens and requests with at least 600 GPT-4 requests guaranteed.
Which AI models does it use, and do I need my own ChatGPT or OpenAI account?
GPT-4o, Claude 3.5, Gemini 1.5 Pro and Llama 3 are cited, and AI Chat advertises 10+ models with a 200k context window. No external account is required: the default Glarity mode comes with an included quota. A ChatGPT mode and a mode using your own OpenAI key, with a temperature setting, exist as alternatives.
Can I cancel my subscription, and can I get a refund?
Cancellation is self-service, from the settings of your personal account. The Japanese legal notice grants a refund without justification within 7 days of the start of service, while section 4(a) of the terms otherwise states that payments are non-refundable.
Is my content used to train AI models?
The question is simply not addressed. Neither the terms of use nor the privacy policy mentions model training, so the publisher neither claims to train on user content nor undertakes not to, and no opt-out is documented. What the terms do say is that you own your inputs and that Glarity may use content to provide and maintain the service, comply with the law and enforce its policies.
Does Glarity offer an API?
Only one public endpoint, and it is a narrow one: GET /api/youtube, described in an OpenAPI 3.0.1 file titled Video Summary Plugin API and designed for a ChatGPT plugin. It requires no authentication and returns a YouTube transcript. There is no general product API and no developer documentation section on the site.
Who publishes Glarity, and which law applies?
The legal notice names Felo Incorporated, at 6-12 Nihonbashikodemmacho, Chuo-ku, Tokyo, with Tatsuya Kanada as the person responsible for operations. Section 8 of the terms applies Japanese law and gives exclusive jurisdiction to the courts of Tokyo. The footer of the shared question-and-answer site askai.glarity.app carries another name, Sparticle Inc.
Conclusion

Should you pick Glarity?

Glarity is a Swiss-army knife for assisted reading inside the browser rather than an enterprise platform, and it should be judged on that basis. Its strongest cards are a genuinely usable free tier of 20,000 tokens a day, permanent and with no trial clock, plus access to GPT-4o, Claude 3.5, Gemini 1.5 Pro and Llama 3 from 10 USD a month on Chrome, Edge, Firefox, Opera and Safari. The core is open source, the product carries no advertising, and the publisher is identifiable and reachable: Felo Incorporated in Tokyo, whose legal notice gives a postal address, a phone number with opening hours and a named operations manager.

The weak side is documentary. The terms of use and privacy policy share one page, dated 04.07.2023 and never revised, and the text is visibly derived from an OpenAI template, referring to service terms and API documentation that do not exist here. There is no DPA, no sub-processor list, no stated hosting country, and not a word about whether user content trains models. Activity signals are mixed as well: the blog was still publishing in August 2026 while the public changelog stopped in June 2024, and the claim of more than a million users is marketing, not an audited figure.

The practical verdict follows from that split. For individual use, and for teams with no documentary compliance requirement, Glarity delivers a lot for the money and costs nothing to try. As soon as a purchase has to clear a data-protection review, covering residency, sub-processors, a training opt-out or a signed agreement, the published material will not answer the questions and another tool will be the safer choice.