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Fluen Online Subtitle Editor

Edit Subtitles Like a Pro.
In Your Browser.

Upload any video or audio file and get accurate, well-timed captions in minutes. Then fine-tune in our professional editor with millisecond timing, AI tools, and real-time video preview. Or import your own SRT files. No installs required.

No credit card required

Desktop Editors Had Their Time. This Is Better.

Desktop Subtitle Editors

  • Install on every machine
  • Files stuck on your local drive
  • No video preview (or clunky add-on)
  • Manual timing only
  • One person at a time
  • No AI assistance
VS

Fluen Cloud Editor

  • Browser-based, no install needed
  • Cloud storage & auto-save
  • Real-time video preview
  • AI-powered timing & segmentation
  • Team collaboration built-in
  • AI wordsmith, translation & glossary

A Professional Editor, Built for the Cloud.

Millisecond-Precise Timing

Adjust start and end times with millisecond precision using keyboard shortcuts or drag handles. See the waveform alongside your cues for intuitive visual editing.

  • Keyboard shortcuts for frame-by-frame adjustments
  • Drag handles for quick timing tweaks
  • Waveform visualization
  • Snap-to-speech boundaries
Timeline & Timing Controls

Synced Video Preview

Watch your video with captions overlaid in real time. Scrub through the timeline and see exactly how your subtitles will appear to viewers.

  • Real-time caption overlay
  • Scrub and seek with timeline sync
  • Preview subtitle styling live
  • No separate video player needed
Synced Video Preview

Split, Merge & Edit Cues

Split long cues into shorter segments, merge adjacent cues, or edit text inline. Smart segmentation suggestions help you maintain professional formatting.

  • One-click cue splitting
  • Merge adjacent cues
  • Inline text editing
  • Smart segmentation suggestions
Cue Split & Merge

Styling & Burn-in

Full control over how your subtitles look. Choose fonts, colors, positioning, and backing plate styles. Preview changes live before exporting burned-in video.

  • Font, size, and color customization
  • On-screen positioning controls
  • Backing plate / shadow options
  • Live preview of burn-in output
Styling & Burn-in Controls

AI Wordsmith

Let AI refine your subtitle text: fix grammar, improve readability, condense long lines. You approve every change, staying in control while the AI does the heavy lifting.

  • AI-powered text refinement
  • Human-in-the-loop approval
  • Condense or expand text on demand
  • Maintains original meaning and tone
AI Wordsmith

Team Collaboration

Work together on subtitle projects. Share workspaces with your team, assign roles, and manage permissions. All in the cloud, no file sharing required.

  • Shared team workspaces
  • Role-based permissions
  • No file emailing or syncing
  • Centralized project management
Team Collaboration

Everything a Desktop Editor Does, and More.

Synced Video Preview

Watch your video with captions overlaid in real time. Scrub through the timeline and see exactly how your subtitles will appear to viewers. No separate player needed.

AI Wordsmith

Let AI refine your subtitle text: fix grammar, improve readability, condense long lines. You approve every change, staying in control while the AI does the heavy lifting.

Styling & Burn-in

Full control over font, color, size, position, and backing plate. Preview your styling live, then export burned-in MP4s with captions baked directly into the video.

Multi-Format Export

Export as SRT, WebVTT, burned-in MP4, or plain text. Each format is optimized for its intended use case, from broadcast delivery to web publishing.

Millisecond Timing — Adjust start and end times with precision down to the millisecond.
Cue Split & Merge — Split long cues or merge short ones to get perfect subtitle segments.
Smart Segmentation — AI splits captions at natural sentence boundaries for readability.
AI Translation — Translate subtitles into 50+ languages with context-aware AI.
Multi-Engine AI — Multiple AI engines. Fluen picks the best one for your content.
Speaker Diarization — Detects speaker changes in multi-person recordings automatically.
Team Collaboration — Shared workspaces with roles, permissions, and centralized projects.
Custom Glossary — Define how brand names and technical terms appear in your captions.
Batch Processing — Upload and process multiple files at once in the background.
Cloud-Based Access — No installs. Access your projects from any browser, anywhere.

Works With All Major Video, Audio, and Subtitle Formats

Upload your video or audio file to generate captions with AI. Already have your own subtitles? Import SRT files during caption review.

Upload
MP4 MOV MKV AVI MP3 WAV SRT*
Export
SRT WebVTT Burned-in MP4 Plain Text

* Import SRT files during caption review to override AI-generated captions.

Your Workflow, Upgraded.

If you're used to Aegisub, Subtitle Edit, or other desktop editors, you'll feel right at home. Everything you know still applies, with cloud benefits on top.

1

Import

Upload your video or audio file, or import existing SRT files.

2

Edit

Use familiar controls alongside AI-powered timing, wordsmith, and translation.

3

Export or Collaborate

Download in any format, or share with your team for review.

Built for Teams That Edit Subtitles Every Day

Post-Production Teams

Deliver broadcast-quality subtitle files with precise timing, professional formatting, and multi-format export.

Localization Teams

Edit and translate subtitles across languages with AI assistance and team collaboration tools.

Content Creators

Caption your videos with a professional editor. No desktop software, no learning curve.

E-Learning Producers

Make courses accessible and compliant with accurate, well-timed subtitles across all your training content.

Corporate Communications

Caption town halls, training videos, and internal comms. Ensure your message reaches every employee.

Podcasters & Audio Creators

Turn episodes into searchable transcripts and video clips with captions for social media distribution.

“We tested several services and after checking with native language persons, Fluen turned out to be number one. Good work!”
MW Sweden
“I am really amazed by how accurate the subtitles are. This will be a big help for our videos.”
HT Germany
“Your tool has already been such a lifesaver in my business. Thanks to you and the team for an amazing product!”
CR Wisconsin, USA

Frequently Asked Questions

Is Fluen a full subtitle editor, or just an AI generator?

Fluen is both. Upload a video or audio file and Fluen generates accurate, well-timed captions with AI. From there, you refine them in a fully featured editor with millisecond timing controls, cue splitting and merging, inline text editing, video preview, and subtitle styling. You can also import your own SRT files if you already have captions. The editor works either way.

Can I import my existing SRT files?

Yes. During caption review, you can import an SRT file to override the AI-generated captions. Your existing cues, timing, and formatting are preserved. From there, you can edit, restyle, and export in any supported format.

How does Fluen compare to Aegisub or Subtitle Edit?

Fluen offers the same core editing capabilities (millisecond timing, cue manipulation, text editing) but runs entirely in your browser. No installation, no local file management. On top of that, Fluen adds AI-powered features like automatic transcription, smart segmentation, AI text refinement (Wordsmith), translation into 50+ languages, and team collaboration. If you're comfortable with desktop editors, you'll feel right at home, with more tools at your disposal.

Can my team collaborate on subtitle editing?

Yes. Fluen supports shared workspaces where team members can access the same projects. You can assign roles and manage permissions so your team can review, edit, and approve subtitles together. No more emailing files back and forth.

What export formats does the editor support?

You can export as SRT (the most widely used subtitle format), WebVTT (for web and HTML5 video), burned-in MP4 (with customizable subtitle styling baked into the video), or plain text transcripts. Each format is optimized for its intended use case.

Can I adjust subtitle timing precisely?

Absolutely. The editor supports millisecond-level timing adjustments. You can type exact timestamps, use keyboard shortcuts for frame-by-frame nudging, or drag cue handles on the timeline. Waveform visualization helps you align captions to speech boundaries with precision.

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 editor and AI captioning engines so you can evaluate the quality before committing to a plan. See pricing →

Can I also generate subtitles from scratch?

Yes. If you don't have existing subtitle files, you can upload a video or audio file and Fluen will generate subtitles automatically using AI. The generated captions appear in the editor, where you can review, refine, and export them. Learn more about subtitle generation →

Your Subtitles Deserve a Real Editor.

Import your files or generate from scratch.
Edit, style, and export, all in your browser.

Try the Editor Free
Or compare plans
Try the Editor Free