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Immersive Translate

Bilingual web, PDF and subtitle translation

About Immersive Translate

Immersive Translate is a bilingual side-by-side translator, mainly browser extensions plus iPhone, iPad and Mac apps, covering web pages, PDFs, ebooks, video and meeting subtitles, and comics. It is closed source; the GitHub repo only ships builds and collects issues, and the terms name Funstory.ai Limited. A 2026-09-28 blog post claims 30 million activated users. Free uses general models; Pro is $9.99/mo billed yearly or $14.99 monthly. Good for heavy readers of foreign-language material; not for teams that need auditable or open-source code.

EditorialUpdated 12 min read

What it is

Immersive Translate is a bilingual translation tool. The Chinese introduction page in the docs says it detects the main content area of a page and places the translation next to the original, "hence the name Immersive Translate". It ships mainly as Chrome, Edge, Firefox and Safari extensions, plus a userscript and apps for iPhone, iPad and Mac. The latest GitHub release, v1.34.4, carries Chrome, Firefox and Safari zips and a userscript file.

Its scope now reaches well past web pages. The GitHub README lists five groups of features: bilingual web translation, including full-page, selection, hover and input-box translation; translation of PDF, EPUB, TXT, HTML and subtitle files, with PDF layout preserved; bilingual subtitles for online video and some meeting platforms; translation of web images, local images and some comic sites; and a choice of translation engines or a custom API, with glossaries, domain settings and context-aware translation on some services. The site navigation also has dedicated entries for Zotero, Google Docs, Steam, AO3 and YouTube Live.

The product is not open source. The README states plainly that Immersive Translate is not open-source software and the repository holds no source code; it exists to publish Release builds and to collect feedback through GitHub Issues. As of 2026-10-25 the immersive-translate/immersive-translate repository had 19,490 stars and 1,149 forks, and GitHub detected no license. It was created at 2022-12-07 20:35 (UTC+8) and last pushed at 2026-10-23 19:57 (UTC+8).

The terms of service name Funstory.ai Limited as the contracting company, and the App Store lists Funstory.ai limited as developer. Funstory.ai's Chinese name is Tuiwen Technology. According to a 36Kr report reposted on its own site, the company was set up in November 2017 to translate Chinese web novels with AI and distribute them to overseas platforms. Translation technology is its home ground; Immersive Translate is its product for everyday readers.

I realized how much the experience of bilingual reading matters.

Immersive Translate Chinese docs introduction (translated)

Core capabilities

First, the side-by-side display itself. Ordinary translators replace the original with the translation, and the Chinese introduction page names this as the first problem Immersive Translate set out to solve: when a sentence reads badly, the user does not have to flip between versions. Hover translation extends the idea: rest the mouse on any paragraph, press a shortcut, and the translation appears below it. The docs explain that the paragraph is treated as the smallest unit so that context is kept. Input-box translation turns any text field on a page into a translator, so a user can write in their own language and send the message in another.

Second, document translation. Layout-preserving PDF translation is handled by BabelDOC, an open-source project under the funstory-ai organization described as "Yet Another Document Translator". It is AGPL-3.0 licensed, was created at 2024-11-13 21:57 (UTC+8) and had 9,761 stars as of 2026-10-25. The App Store description says the paid PDF translation also recognizes complex formulas, tables and text inside images in a PDF. EPUB books can be exported in bilingual form, and subtitle files and TXT can be translated directly.

Third, video and meeting subtitles. Bilingual YouTube subtitles are unlimited on the free plan. Videos without subtitles can get AI-generated ones, which requires a paid plan. The changelog records that live meeting subtitle translation can be switched on from the floating ball on Zoom, Google Meet and Microsoft Teams. Version 1.34.2, merged on 2026-10-18, added subtitle translation on the NVIDIA learning platform and full subtitle downloads from Disney+.

Fourth, a choice of translation services. The Chinese docs list more than 30 services, naming DeepL, OpenAI, Microsoft Translator, Google Translate and Tencent Translate. In the changelog, version 1.15.2 (merged 2025-03-02) added Grok, Ollama, Groq and Azure OpenAI; Ollama lets models running on the user's own machine plug in. Version 1.34.2 added Xiaomi MiMo, let custom AI services edit the request body JSON, and allowed custom API URLs on more services.

Fifth, image and comic translation. Offline image translation is unlimited on the free plan, and comic translation comes with 3,000 images a month on both Pro and Max. The changelog keeps adding comic sites such as BookWalker, ManhwaWeb, RidiBooks and toptoon.com, and some models now handle traditional Mongolian script.

Who it's for / Not for

Good fit: people who read a lot of foreign-language web pages, papers, technical docs and news. Side-by-side text lets readers skim the translation and refer to the original when a sentence looks wrong; the Chinese introduction page lists "learning English while reading" as one benefit of reading this way.

Good fit: people who watch a lot of foreign-language video or join meetings in other languages. Bilingual YouTube subtitles are free, meeting subtitles cover Zoom, Google Meet and Microsoft Teams, and paid plans can generate subtitles for videos that have none.

Good fit: people who already hold a DeepL or LLM API key. The README says a custom API can be connected, and the changelog adds local model services such as Ollama; the free features plus one's own API cover most everyday use.

Good fit: researchers who manage papers in Zotero and need whole PDFs translated. The site has a Zotero translation entry, and BabelDOC keeps the layout.

Not a fit: teams whose organization requires open-source software or needs to audit extension code. The README says the product is not open source, and the Firefox add-on page lists the license as All Rights Reserved.

Not a fit: people handling confidential material that may not go to any outside service. The privacy policy says submitted text or files are kept temporarily only as far as needed to provide translation and are deleted afterwards; even with only a local model, the extension itself is closed source, so the decision belongs to the security team.

How it compares

Against the browser's built-in translation, the difference is presentation. Built-in translation usually replaces the whole page; Immersive Translate keeps the original, places the translation alongside it, and lets the user pick the service. The cost is longer pages and the occasional broken layout on complex sites; the changelog is full of site-specific fixes.

Against DeepL Pro, the billing units differ. The DeepL Pro pricing page (as of 2026-10-25), priced in EUR, lists Individual at 7.49 EUR per month billed annually, with 300,000 characters a month, 3 file translations and 1 glossary; Team is 24.99 EUR per user per month billed annually. Immersive Translate Pro measures its quota in tokens, and DeepL Pro is on its list of advanced models.

Inference: for side-by-side web and video reading, Immersive Translate Pro covers more ground; for formal document translation where one engine's consistent wording matters, DeepL's own subscription is the more direct route. Because the quota units differ, the prices cannot be converted one-to-one.

Against open-source alternatives. fishjar/kiss-translator describes itself as a simple, open-source bilingual translation extension and Greasemonkey script; it is GPL-3.0, had 13,007 stars as of 2026-10-25, and was created at 2023-07-18 15:20 (UTC+8). mengxi-ream/read-frog (Read Frog) positions itself as an open-source alternative to Immersive Translate with a focus on AI language learning and flashcards; it is also GPL-3.0, with 10,179 stars, created at 2025-04-17 07:32 (UTC+8).

Inference: the two open-source extensions suit users willing to bring their own translation API who value auditable code; Immersive Translate's edge is in features that need server support, such as layout-preserving PDF, comics, meeting subtitles and mobile apps.

Against its own past. immersive-translate/old-immersive-translate is the early open-source implementation, MPL-2.0 licensed, with 919 stars, now archived. Its code can still be read and forked, but it will not be updated.

Getting started

Step one: install from the browser's extension store. The README's flow is short: install the extension, open a page, and click translate to see both languages. The Chrome Web Store lists version 1.34.2, updated on 2026-10-19; the Firefox add-on page lists version 1.33.3.

Step two: choose a translation service. The general models bundled with the free plan need no setup; users with their own keys can switch to DeepL, OpenAI or other services in settings, or connect a custom API or Ollama.

Step three: open the dedicated feature for each job. PDFs and ebooks are uploaded through the document translation entry on the site, video subtitles are switched on from the player page, and meeting subtitles from the floating ball. Version 1.34.2, merged on 2026-10-18, added a Simple Mode that enables only the chosen features among video subtitles, selection translation, AI writing, hover translation and input-box translation; switching back to Full Mode restores the earlier settings.

Step four: install the app on mobile. The App Store lists the app for iPhone, iPad and Mac, at 112.7 MB, rated 16+.

To try a paid plan, the pricing page offers a 3-day free trial. The membership agreement says the plan is charged automatically for the chosen cycle unless cancelled before the trial ends; a refund is allowed only once, within 72 hours for annual plans and 24 hours for monthly plans.

Pricing & license

There are three personal plans, Free, Pro and Max, plus a team plan. USD prices come from the Immersive Translate pricing page (as of 2026-10-25) and the membership agreement (updated 2026-08-07).

Free: $0. It uses general models such as SiliconFlow GLM-4 Flash and HY-MT, with unlimited web page, PDF, YouTube bilingual subtitle, bilingual ebook, input-box and offline image translation, subject to anti-abuse rules.

Pro: $9.99 per month billed annually, or $119.88 a year, against a struck-through $179.88 a year on the pricing page. The membership agreement lists the monthly-billing price as $14.99 per month. Pro includes 20 million advanced-model tokens a month, with DeepSeek, Qwen, Gemini, GPT and GLM models and DeepL Pro named on the pricing page, plus 1,000 PDF Pro pages, 1,000 minutes of AI video subtitles and 3,000 comic images a month, and settings sync.

Max: $19.99 per month billed annually, or $239.88 a year, against a struck-through $479.88 a year on the pricing page. The membership agreement lists the monthly-billing price as $39.99 per month. Max includes 50 million advanced-model tokens and 2 million top-tier-model tokens a month, with Claude, Gemini Pro, GPT, Kimi and GLM models on the top-tier list, plus quick customer support.

In-app purchases on the App Store are priced differently from the website. The App Store page (as of 2026-10-25, priced in USD) lists Pro at $9.99 monthly and $79.99 yearly, and Max at $34.99 monthly and $289.99 yearly.

License: Immersive Translate is closed-source software. The README says it is not open source, the GitHub repo has no license file, and the Firefox add-on page says All Rights Reserved. The old open-source project is MPL-2.0, and BabelDOC is AGPL-3.0.

Risks & limits

Closed source is the main limit. The extension can read the pages a user browses, yet its code is not public, so an organization has to rely on the vendor's privacy policy and certifications. The trust center says the company has passed ISO 27001 and ISO 27701 audits; the privacy policy says submitted text or files are held only temporarily as needed to provide the service and deleted afterwards; the README says that within the official translation services it covers, translated content is not used to train AI models. With a custom API, where content goes depends on the chosen service.

The model list changes. The membership agreement says actual models and quotas follow what the app shows in real time, and that model changes are not grounds for breach or refund. Buying a yearly plan for one named model means accepting that the list may change.

Trials turn into paid plans. If the 3-day trial is not cancelled before it ends, the plan is charged; a refund can be requested only once, within a short window.

The terms of service restrict use in some regions and for some purposes; see the terms for details.

User numbers are vendor figures. The official blog claims more than 30 million activated users worldwide. The Chrome Web Store shows 3,000,000 users and a 4.6 rating from about 3,200 ratings. The Firefox add-on API shows 113,102 average daily users (counted in UTC). On Firefox, 493 ratings average 3.74. These figures measure different things and cannot be added up.

The docs are out of sync. The Chinese docs say more than 30 translation services are available, the English docs say more than 10. As of 2026-10-25 the repository had 330 open GitHub issues out of 3,210 in total.

How it got here

It began with a bilingual book. The Chinese introduction page carries a first-person note that opens "Hi, I'm Owen": after reading a bilingual edition of Little Women, the author realized how much bilingual reading mattered and built Immersive Translate; once released, many people with the same need started using it heavily, and PDF, EPUB, subtitle and TXT translation followed.

The earliest public traces date from November 2022. The old open-source repository, old-immersive-translate, was created at 2022-11-05 01:49 (UTC+8) under MPL-2.0. The Firefox add-on listing was created at 2022-11-06 20:26 (UTC+8).

From December 2022 releases went closed source. The current immersive-translate repository was created at 2022-12-07 20:35 (UTC+8); its first commit, 31016d0, has the author name Owen and the message Initial commit. The old repository's last push was at 2023-01-17 04:14 (UTC+8), and it was archived after that.

It was acquired in May 2023. A creator article on Tencent News dated 2023-05-25 relays the developer's announcement: Immersive Translate had gathered 400,000 users in five months and had been acquired by Tuiwen Technology; the two sides would set up an independent subsidiary to develop and run it, the developer would keep leading product and engineering for the extension, and no price was disclosed. This is a relayed report, quoted as the article states it. The terms of service now name Funstory.ai Limited as the contracting party.

Releases come fast. The repository has 558 tags: 522 starting with v and 36 nightly. The 0.x series began with v0.0.9 at 2022-12-27 16:57 (UTC+8). The last 0.x release was v0.12.14 at 2024-01-04 22:01 (UTC+8). The 1.x series began with v1.1.0 at 2024-01-06 02:58 (UTC+8), and the latest, v1.34.4, came out at 2026-10-23 19:57 (UTC+8). Counted in UTC, new tags per year were 49 in 2022, 257 in 2023, 85 in 2024, 112 in 2025 and 55 in 2026 up to 2026-10-25.

The product line then widened. The BabelDOC repository was created at 2024-11-13 21:57 (UTC+8) and later became the engine for layout-preserving PDF translation. Version 1.15.2 (merged 2025-03-02) added Ollama and other services. At 2026-09-28 17:03 (UTC+8) the official blog announced more than 30 million activated users worldwide.

Commits in the repository are mostly automated releases. The main branch has 2,300 commits. Counted in UTC, commits per year were 86 in 2022, 1,875 in 2023, 109 in 2024, 152 in 2025 and 78 in 2026 up to 2026-10-25. In the 30 days from 2026-09-25 08:00 (UTC+8) there were 7 commits, the latest being 2ff98f3, "update dist", at 2026-10-23 19:57 (UTC+8). The GitHub contributors API returns 20 accounts, led by github-actions[bot] with 1,385, followed by two personal accounts with 542 and 249. The git history has 24 distinct author names.

Our verdict

Immersive Translate turned one simple interaction, reading the original and the translation side by side, into a full product: web pages, documents, subtitles, meetings and comics all get bilingual views, with dozens of translation services behind them. The price is closed code, dependence on the vendor's servers, and pricing that differs from channel to channel.

The free plan works with a user-supplied DeepL or LLM key; layout-preserving PDF translation, AI subtitles and comic quotas come with Pro and Max.

The extension is closed source, and the README says it is not open-source software; KISS Translator and Read Frog are open-source alternatives.

Inference: judging by the commit and tag pattern since 2023, development happens in an internal repository and the GitHub repo serves only for releases and feedback; outside users see changes mainly through the changelog and app store release notes.

Why it stands out

Immersive Translate shows the original text and its translation side by side on any web page, PDF, subtitle, or ebook. That single interaction decision, keeping both languages in view, is the core of the product.

Owen started it as a personal tool and grew it into a business with a global user base, supporting dozens of translation providers including local models. The extension works because it respects the page it is translating.

It keeps the original and the translation side by side on web pages, PDFs, subtitles and ebooks, and supports dozens of translation providers, including local models.

Sources

Official

  1. immersive-translate/immersive-translate on GitHubGitHub · Accessed Oct 25, 2026
  2. immersive-translate README (in Chinese)GitHub · Accessed Oct 25, 2026
  3. immersive-translate commit 31016d0: Initial commitGitHub · Accessed Oct 25, 2026
  4. immersive-translate commits on mainGitHub · Accessed Oct 25, 2026
  5. immersive-translate tagsGitHub · Accessed Oct 25, 2026
  6. immersive-translate releasesGitHub · Accessed Oct 25, 2026
  7. immersive-translate release v1.34.4GitHub · Accessed Oct 25, 2026
  8. immersive-translate issuesGitHub · Accessed Oct 25, 2026

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