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Add Subtitles to Your Videos.
Actually Good Ones.

Captions so accurate you barely need to edit. Proper punctuation, natural line breaks, 50+ languages. Export as SRT, VTT, TTML, and more.

Try it Free · No credit card required

Powering teams at
Adobe Roche Airbus NBCUniversal L'Oréal Salesforce Siemens
Natural Readability Multi-Engine AI 50+ Languages
Fluen Studio — AI subtitle editor
1,500,000+
Minutes Processed
50+
Languages Supported
99.2%
Accuracy Rate

Our Subtitle Intelligence Stack

OpenAI Deepgram DeepL AssemblyAI Anthropic

We orchestrate multiple transcription, translation, and AI engines. Our proprietary segmentation technology transforms raw output into natural, well-timed cues ready for the screen.

Subtitles engineered for readability.

Our segmentation engine turns raw transcription into natural, well-paced cues by analyzing speech patterns, structure, and timing. We automatically route to the best engine for your content (OpenAI, Deepgram, or AssemblyAI), and you can add domain terms to your Glossary for greater accuracy.

El mayor reto de la localización de video es mantener los subtítulos legibles sin perder la fidelidad al significado original.
00:00:12.440
#1 CPL: 38
CPL: 35

The biggest challenge with video

localization is keeping subtitles readable

00:00:15.280
00:00:15.280
#2 CPL: 34
CPL: 30

while staying true

to the original meaning.

00:00:18.160
Fluen segmenta en pausas naturales para una lectura sin esfuerzo.
00:00:18.160
#3 CPL: 40
CPL: 33

Fluen segments cues at natural pauses

so viewers never feel rushed.

00:00:21.600
Natural line breaks 42 CPL limit Optimal reading speed

Not All Captions Are Created Equal.

Drag to compare.

GENERIC
00:00:02,340 → 00:00:07,120
when we first started looking at the data the patterns
were really quite surprising we didnt expect
00:00:07,120 → 00:00:10,800
to see that kind of growth especially in the first quarter
00:00:14,500 → 00:00:19,200
the kubernetes cluster was running on aws easy two instances and we used post gress for the backend
No punctuation No caps Jargon mangled
FLUEN
00:00:02,340 → 00:00:05,780
When we first started looking at the data,
the patterns were really quite surprising.
00:00:05,780 → 00:00:10,800
We didn't expect to see that kind of growth,
especially in the first quarter.
00:00:14,500 → 00:00:19,200
The Kubernetes cluster was running on
AWS EC2 instances with PostgreSQL.
Proper punctuation Smart line breaks Terms recognized

Built for Anyone Who Needs Great Subtitles

YouTubers & Creators

Grow your audience with accurate captions in every language your viewers speak.

Podcasters

Turn episodes into searchable transcripts and ready-to-post video clips.

Corporate Training

Caption onboarding and compliance videos for global, multilingual teams.

Marketing Teams

Localize campaign videos fast without waiting on manual translation.

E-Learning

Make courses accessible and boost comprehension with professional subtitles.

Agencies & LSPs

Speed up subtitle delivery with AI-first drafts your editors can refine.

“Can't I just use free auto-captions?

“YouTube or Zoom already auto-caption my videos.”

They do — without punctuation, capitalization, or line breaks. Your viewers notice. Upload to Fluen, get broadcast-quality captions, and export a clean SRT or burned-in MP4 in minutes.

“I'll just fix the auto-captions manually.”

A 30-minute video has ~400 subtitle cues. At 99.2% accuracy with smart segmentation, Fluen handles the punctuation, line breaks, and speaker changes for you. Most files need barely any edits.

“Sounds great, but I have hundreds of videos.”

Upload them all. Fluen processes files in parallel, so you can queue an entire content library and download clean SRTs for everything at once. Start with 3 free files to see the quality for yourself.

The Tools Behind Good Looking Subtitles

Multi-Engine AI

We route your file to the best speech engine for your content. Different engines for interviews, podcasts, lectures, and noisy environments. The result is consistently higher accuracy than any single engine can deliver on its own.

Built-in Editor

Review captions synced to your video. Adjust timing, fix a word, split or merge cues. Everything runs in your browser, so there's nothing to download or install. Just open your project and start editing.

Styling & Burn-in

Full control over font, color, size, and position. Generate burned-in MP4s ready to upload to YouTube, Instagram, or any platform. Preview your styling in real time before exporting.

Custom Glossary

Define how technical terms, brand names, and industry jargon should appear in your captions. Your glossary ensures Kubernetes stays “Kubernetes” and not “Cooper Netties.” Once saved, it applies automatically to every future upload.

Batch Processing

Upload an entire content library. Queue files, process in parallel, and download subtitle files for all of them at once. Ideal for teams managing large backlogs of video or audio content.

Translate Your Subtitles Into Any Language.

Once your captions are ready, translate them into 50+ languages with a single click. Fluen's context-aware AI doesn't just swap words — it re-segments every cue for the target language, respecting character-per-line limits and natural reading flow. The result: subtitles that read like they were written by a native speaker.

Spanish
French
German
Portuguese
Japanese
Chinese
Korean
Arabic
Italian
Dutch
Russian
Polish
Turkish
Hindi
Swedish
Explore Translation Features
“Ran about 40 videos thru Fluen last month. The punctuation and line breaks are basically perfect, I maybe edited 2-3 cues per file. Huge timesaver vs what I was doing before.”
Marcus T. Baltimore, USA
“We produce training vids for clients in 3 languages. Used to outsource the subtitles, now we just run everything through Fluen and export SRTs. Way faster and honestly more accurate.”
Laura S. Winnipeg, Canada
“I was not expecting so good results on the first try. The burned-in MP4 is very useful, I can put subtitles on my youtube shorts directly without uploading SRT files separate.”
Tomáš K. Prague, Czech Republic
“We tested it with a conference recording that had very bad audio and it still detected the speakers correct. Much better than what we were using before, honestly.”
Daniel R. Madrid, Spain

Frequently Asked Questions

How do I add subtitles to my video?

Upload your video to Fluen, and our AI generates accurate captions automatically. Review and edit them in our built-in subtitle editor, then export as SRT, WebVTT, TTML, and more to upload to YouTube, Vimeo, or any platform. You can also choose burned-in MP4 to have the subtitles embedded directly into your video file.

How accurate are the AI-generated subtitles?

Fluen achieves up to 99.2% accuracy by routing your file to the best speech-to-text engine for your content type, language, and audio quality. Combined with our smart segmentation, captions come out well-punctuated, properly capitalized, and split at natural sentence boundaries.

What video and audio formats are supported?

Fluen supports all major video formats including MP4, MOV, MKV, and AVI, as well as audio formats like MP3, WAV, M4A, and FLAC. If you already have subtitle files, you can import SRT files directly during the caption review step.

Can I burn subtitles directly into my video?

Yes. Fluen can generate a burned-in MP4 with your subtitles embedded directly into the video. You have full control over font, size, color, position, and background opacity, so your captions look exactly how you want them.

Can I also translate my subtitles?

Absolutely. Once you've generated and reviewed your captions, you can translate them into 50+ languages with Fluen's AI translation engine. Translations are context-aware and automatically re-segmented for each target language. Learn more about subtitle translation →

Does Fluen support vertical (portrait) videos?

Yes. Fluen works with any aspect ratio, including vertical 9:16 videos from TikTok, Instagram Reels, and YouTube Shorts. Captioning and burned-in export both handle portrait orientation automatically, so your subtitles are always positioned correctly.

Is there a free plan?

Yes. You can sign up and process your first 3 files completely free, no credit card required. This gives you access to the AI captioning engines and the built-in editor so you can evaluate the quality before committing to a plan. See pricing →

Your Next Video Deserves Better Subtitles.

Upload your first file. No credit card. No commitment.

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