CastReader adds a Listen button to every email in Outlook.com and Office 365. One click and the email is read aloud in a natural AI voice — with paragraph highlighting that follows along as you listen.
CastReader detects Outlook and adds a Listen button next to the email subject
Open any email in Outlook.com or the Office 365 web app and a Listen button appears next to the subject heading. CastReader detects the ARIA heading role that Outlook uses and positions the button right where you're already looking.
CastReader targets Outlook's document-role container to extract just the email body. No reading-pane chrome, no folder list, no ribbon UI — clean paragraph extraction with quoted-reply filtering, so you hear the message and not the thread's history.
As each paragraph is read aloud, it's highlighted in the email body and the view scrolls automatically. Click any paragraph to jump ahead or back — perfect for long business emails and newsletters.
Switch to another email and the Listen button moves with you. Outlook reuses the same heading element when you navigate — CastReader detects the text change and updates the button state. No stale buttons, no ghost playback.
Personal mail on outlook.live.com, work or school accounts on outlook.office.com and outlook.office365.com — the same Listen button on all of them, in Chrome and Microsoft Edge.
Halfway through a long newsletter when you have to leave? Send it to your phone with one click and keep listening in the CastReader app from the same spot.
CastReader auto-detects the language of each email and matches a natural AI voice — an international inbox reads correctly without touching a setting.
Add the free extension from the Chrome Web Store or Edge Add-ons — no account needed.
In Outlook.com or Office 365, a Listen button appears next to the subject line automatically.
The email is read in a natural AI voice while each paragraph highlights. Click any paragraph to jump; set 1.5–2× speed for triage.
Switch emails and the button follows — or send the audio to the CastReader app on your phone and finish on the move.
Microsoft has built Read Aloud and Immersive Reader into several Office surfaces — Word, OneNote, Teams, and the classic desktop Outlook app (View > Immersive Reader). But what you get in Outlook on the web varies by version and tenant, and many mailboxes don't expose a read-aloud button at all. Even where it exists, it leans on system speech voices, which sound robotic next to modern AI voices.
The Outlook web app is also a hard target for generic page readers. It's a React-based single-page application with a complex DOM: emails render inside elements with ARIA document roles, and the subject line uses an ARIA heading role whose text updates dynamically. Generic extensions tend to read the entire interface — folder pane, ribbon, calendar sidebar and all.
CastReader handles this by detecting Outlook's DOM patterns specifically. It finds the heading element with the allowTextSelection class for the subject and extracts email content from the document-role container. When you switch emails, Outlook reuses the same heading DOM element and just updates the text — CastReader tracks both the element reference and the text content to detect email changes correctly.
For anyone who processes dozens of emails daily, listening instead of reading is a real productivity gain. Commute time, lunch breaks, multitasking at your desk — CastReader turns the inbox into a podcast-like stream. And because extraction is clean (no signatures, no footers, no quoted-reply chains), a 20-message thread plays as one message: the newest one.
It's also one tool for your whole mail life: the same Listen button appears in Gmail and other webmail, with the same voices and controls. CastReader is free to start — standard voices, no signup — and CastReader Pro unlocks premium ultra-realistic voices and more listening time. Privacy stays simple: it reads the email you're viewing to generate audio, doesn't store your messages, and never accesses your Outlook account.
Everything about listening to Outlook emails
In some places, yes. The classic desktop Outlook app has Read Aloud via Immersive Reader, and what's available on the web varies by version and tenant. CastReader gives you one-click listen on any Outlook you open in the browser — natural AI voices and paragraph highlighting instead of system speech.
Install CastReader from the Chrome Web Store. Open any email in Outlook.com or Office 365 — a Listen button appears next to the subject. Click it and the email reads aloud with paragraph highlighting.
Yes. CastReader works on outlook.live.com (personal) and outlook.office.com / outlook.office365.com (work or school). Same Listen button, same experience.
No. CastReader extracts only the email body from Outlook's document container. It skips the folder list, ribbon, reading-pane chrome and quoted reply history — you hear just the email content.
Yes. Quoted-reply filtering keeps long threads listenable: you hear the new message, not the five older ones stacked below it, and not the footer boilerplate.
CastReader is a Chrome/Edge browser extension, so it works with Outlook in the browser. In the desktop app, use Microsoft's built-in Read Aloud (View > Immersive Reader) — or open the same mailbox at outlook.office.com to use CastReader.
Yes. CastReader is available for both Chrome and Edge — install it from the Edge Add-ons store. Since many Outlook users live in Edge, this is fully supported.
CastReader reads the email body text only — not attachments. For PDFs, open the attachment in a browser tab and use CastReader's PDF reading separately.
Yes — 40+ languages with natural AI voices, auto-detected per email. English, Spanish, French, German, Chinese, Japanese and more all read with proper pronunciation.
Yes. Set 1.5–2× speed for inbox triage — newsletters and status updates go by quickly; click any paragraph to replay what you missed.
Yes — use Send to Phone. Start playback on desktop, click once, and the audio continues in the CastReader iOS or Android app from the same spot.
Free to start — standard voices, no signup. CastReader Pro (optional) unlocks premium ultra-realistic voices, more listening hours, voice cloning and AI document analysis.
CastReader reads the text of the email you're viewing and sends it to our voice API to generate audio. We don't store your messages and we never access your Outlook account or mailbox.
Download the CastReader app to listen to your uploaded documents anywhere.
Hard numbers — not vibes — from authoritative sources
$2.22 billion
US audiobook sales in 2024, up 13% year-over-year (Publishers Weekly / Audio Publishers Association)
Source →51%
of US adults have listened to an audiobook in 2025 — roughly 134 million people (APA Consumer Survey 2025)
Source →2.2 billion
people globally with near- or far-vision impairment (WHO Fact Sheet, 2024). TTS is the primary access path for digital reading content.
Source →78%
of audiobook listeners multitask while listening — commute, chores, exercise (Audiolibrix Great Audiobook Survey, 2024)
Source →27.2 minutes
average single-trip US commute in 2024, up from 26.8 (US Census ACS via Statista). That's nearly an hour each day of audio-only time.
Source →effect size 0.35
measured comprehension lift from TTS for reading-disabled students across 22 studies (Wood, Moxley, Tighe & Wagner, Journal of Learning Disabilities, 2018)
Source →15.5 million
US adults with ADHD per CDC 2024 — about half diagnosed in adulthood (CDC MMWR, October 2024)
Source →Every Chrome Web Store review below is verifiable at the link in each card. We don't hide negative feedback — we answer it within 24 hours.
“This is 1 of the best TTS and its smooth. If this is truly free i'll keep this 100%. Every other TTS says its free but has a secret. They interrupt or they just say better ai voices pay. But i like this voice. I've tried loads and this is 1 of the best ones that actually says free.”
“Works perfectly on vivaldi. One suggestion though. I wish it had a play button appear next to a paragraph when we hover over it. Just like in the case of speechify.”
“Extremely user friendly short keys. Placed forward backward and speed up down as Natural as it could be. Voices are great and smooth. I would recommend it over many hyped products.”
“At the very least it's better than many paid TTS models. Still not as good as ElevenReader or LAP, but maybe the best free model for TTS.”
“So glad I can finally switch voices! The default was fine but I found one I actually enjoy listening to for hours. Small thing, huge difference.”
“Best one i found, user friendly, and great voice over.”
“ChatGPT's long answers are finally listenable. Let it generate while I listen — doubles my productivity. Love the inline button next to each response.”
“I tried using this add-on to listen to an ebook on the O'Reilly learning platform, and it works smoothly. However, it always restarts from the first paragraph whenever I scroll or select a different paragraph. Please consider adding a bookmark or checkpoint feature so users can mark where the reading should begin.”
↪ Founder reply
Replied by CastReader founder Yan Xu within 48 hours: acknowledged the issue, shipped a bookmark feature in the following release. Reviewer's verbatim feedback drove the v1.2 roadmap.
“Need to highlight text and select it.”
“Hard to select text.”
↪ Founder reply
Replied by CastReader founder Yan Xu within 24 hours: apologized, asked which site/browser the issue occurred on, provided a workaround using the keyboard shortcut, and offered direct support at support@castreader.ai.
We re-test, re-write, and ship continuously. Every entry has a real date.
Rewrote landing pages with verbatim Chrome Web Store testimonials, real audiobook market data, and tested-12-extensions methodology. Every claim now has a sourceable link.
Telegram audio streaming now auto-turns pages reliably across Kindle Cloud Reader and Apple Books. Reduces session interruptions by ~70% in internal testing.
Wrote up the OCR pipeline: how CastReader handles Amazon's 184 random font alphabets and 361 unique glyphs per Kindle book. Shared in dev.to.
Native macOS app reads Kindle for Mac with word-level highlighting. Floating player + system-wide hotkeys. No browser needed.
Ranked #10 in Daily, 99 upvotes, 4 community comments shaped the v1.2 roadmap.
Switched from older TTS engines to Kokoro neural voices. User reviews shifted from 'usable but robotic' to 'enjoy listening for hours' (verbatim from review by patrick chiang).
OCR success rate improved from 78% to 89% on English-language Kindle books. Multi-column page detection added for academic PDFs.
I built CastReader because I owned hundreds of Kindle books and couldn't listen to them on my morning runs without buying separate Audible copies. The technical problem — Amazon's Cloud Reader font encryption — turned out to be solvable with OCR. The product problem — making it actually pleasant across phones, desktops, and 40+ languages — took two years of iteration. We're a small team. I answer every Chrome Web Store review personally (see testimonials above — including the 3-star and 1-star ones). If something's broken or missing, email support@castreader.ai.
— Yan Xu, founder
Last reviewed: · CastReader Team — reviewed against 2025 testing data
Free to start, no signup — upgrade to CastReader Pro for premium voices and more listening hours. Install and start listening.
★★★★★ 4.7 · Free to start · No login · Optional Pro