Caption.IM

Caption.IM is a privacy-first AI captioning assistant designed exclusively for macOS. It transforms any audio playing on your Mac into real-time captions, instant translations, recordings, and structured meeting notes, all powered by local AI processing on your device. Unlike browser extensions or meeting bots that require integration with specific platforms, Caption.IM captures system audio directly, enabling it to work across virtually any application on your computer. This includes popular video conferencing tools like Zoom, Google Meet, and Microsoft Teams, as well as media platforms such as YouTube, online courses, podcasts, livestreams, webinars, and even pre-recorded videos. The main value proposition of Caption.IM is its combination of powerful real-time transcription and translation capabilities with a strong emphasis on user privacy. By processing all speech recognition and language tasks locally on your Mac, especially on Apple Silicon (M1, M2, M3, and later), your conversations and audio data never leave your device. This eliminates the need for third-party servers or bots joining your meetings. Caption.IM is designed for remote workers, students, content creators, researchers, multilingual teams, and anyone who needs to improve accessibility, productivity, and information equity. It turns any spoken conversation into searchable, translatable, and actionable knowledge instantly, all within an elegant and frictionless user interface.

Real-Time Transcription

Caption.IM generates live captions for any audio source on your Mac with remarkable speed and accuracy. Whether you are in a video call, watching a recorded lecture, or listening to a podcast, the application transcribes spoken words into text in real time. The transcription appears in a floating subtitle window that overlays seamlessly on your screen, ensuring you never miss a word. The audio pipeline has been optimized to convert audio to a source-stage 16 kHz mono Float32 format, which significantly improves transcription accuracy and reduces latency. This feature is indispensable for individuals who are deaf or hard of hearing, as well as for anyone who wants to review or search through spoken content later.

Instant Translation

Break down language barriers with Caption.IM's real-time translation capabilities. The application can translate captions from one language to another as the audio plays, allowing you to understand content in multiple languages instantly. This is particularly valuable for multilingual teams, international meetings, online courses in foreign languages, or consuming global media. The translated subtitles appear alongside the original transcription in the same floating window, providing a clear and immediate understanding of the conversation. Because processing is done locally, translations are fast and do not require an internet connection, ensuring your data remains private and secure.

Floating Subtitle Window

The user interface of Caption.IM is designed to be elegant and unobtrusive. The captions are displayed in a transparent, floating subtitle window that integrates smoothly with the macOS desktop environment. You can reposition this window anywhere on your screen, resize it, and adjust its transparency to suit your workflow. This design ensures that captions are always visible without blocking important content in your main application window. The floating window is a key differentiator, as it works with any app and does not require any modifications to the software you are using. It provides a frictionless experience where you simply open Caption.IM and start seeing captions immediately.

AI Meeting Summaries

Beyond live transcription, Caption.IM can automatically generate structured summaries and key insights from your conversations. After a meeting, lecture, or discussion, the application analyzes the transcribed text to produce concise summaries, highlight key points, identify action items, and even create mind maps. This feature transforms long audio sessions into easily digestible and actionable information. It saves significant time by eliminating the need to manually review hours of recordings. The summaries are generated using local AI, ensuring that sensitive business discussions or personal conversations remain confidential and are never uploaded to the cloud.

Remote Meetings and Video Conferencing

For professionals who spend their days in virtual meetings on platforms like Zoom, Google Meet, or Microsoft Teams, Caption.IM provides real-time captions that ensure you never miss critical information. It is especially useful in noisy environments, for non-native speakers, or for participants with hearing impairments. The AI meeting summaries automatically generate notes, action items, and key decisions, allowing you to stay focused on the conversation rather than taking manual notes. This dramatically improves productivity and meeting follow-through.

Online Learning and Education

Students and educators can use Caption.IM to enhance the online learning experience. Live captions make lectures, tutorials, and webinars more accessible, especially for complex subjects or when the instructor speaks quickly. The real-time translation feature allows students to follow courses conducted in a foreign language. After a class, the recorded transcript and AI-generated summaries serve as excellent study aids, making it easy to review key concepts, search for specific topics, and create study notes.

Content Creation and Media Consumption

Content creators, journalists, and researchers can benefit from Caption.IM when analyzing podcasts, interviews, webinars, or recorded videos. The application can transcribe long audio files quickly, providing a searchable text record. This makes it easy to find specific quotes, verify information, or repurpose spoken content into written articles, blog posts, or social media updates. For casual users, it adds a convenient way to watch YouTube videos or listen to podcasts with subtitles, improving comprehension and enjoyment.

Accessibility and Inclusion

Caption.IM is a powerful tool for improving digital accessibility. Individuals who are deaf or hard of hearing can use it to participate fully in audio-based activities, from work meetings to entertainment. The local processing ensures that accessibility features are available without compromising privacy or requiring an internet connection. It also helps individuals with auditory processing disorders or those who simply prefer reading along with audio. By providing real-time captions for any application, Caption.IM promotes information equity and ensures that everyone can access and understand audio content.

What applications is Caption.IM compatible with?

Caption.IM is designed to work with virtually any application that produces audio on your Mac. It captures system audio directly, so it is compatible with video conferencing tools like Zoom, Google Meet, and Microsoft Teams, streaming platforms like YouTube and Netflix, media players, online course platforms, podcast apps, and any other software that outputs sound. There is no need for browser extensions or specific app integrations.

How does Caption.IM ensure my privacy?

Privacy is a core principle of Caption.IM. All speech recognition and language processing tasks are performed locally on your Mac using on-device AI. Your audio data, transcriptions, and translations never leave your computer. No bots join your meetings, and no data is sent to external servers. This ensures that your conversations, whether personal or professional, remain completely confidential and secure.

Does Caption.IM work on all Mac models?

Caption.IM is optimized for Mac computers with Apple Silicon (M1, M2, M3, and later chips). It requires macOS 15.6 or later. While it may function on older Intel-based Macs, the performance, speed, and efficiency are best on Apple Silicon devices, where it delivers ultra-fast speech recognition with minimal latency and efficient power usage.

Can I save and review my transcriptions later?

Yes, Caption.IM allows you to record important audio and save the resulting transcriptions. You can also generate structured summaries, key points, and action items from your recorded conversations. This turns your spoken content into a searchable and reviewable knowledge base, which is ideal for meetings, lectures, and research. All saved data remains on your local device.