HeyGen's Proofread tool (also called Review & Edit) lets you review and adjust the translated script, voices, and timing before generating the final video giving you full control over translation accuracy and style.
🛎️ Note: Proofread is available to all paid plan users. Proofreading is also available via API! Click here for more info.
Starting a Proofread Project
Before configuring any language settings, you first need to import your video.
You have three options to add a video:
Browse local files: Drag and drop your video into the designated area, or click to upload a file from your device (MP4, MOV, or WEBM format, up to 5 GB).
Select an existing project: Choose a video you've already created within your HeyGen workspace.
Paste a URL: Paste a direct link from YouTube or Google Drive. Vimeo links are not currently supported.
On the translation setup page, configure your Source Language, Target Language, Engine, and any Advanced settings. Then select Review & Edit (instead of Translate) to create a Proofread project.
⚠️ Brand Glossary must be selected at the time you create the Proofread. It cannot be added to an existing proofread — you would need to start a new one.
You can also upload an SRT file before generating the Proofread to provide the translated text in advance. If you plan to upload an output SRT file, attach it before creating the Proofread — segment counts may not match if you try to upload it afterward (short neighboring segments get merged when the Proofread is built).
For more on Advanced settings, see the Get Started article.
Click Review & Edit to submit your Proofread project and wait for it to generate.
Editing Your Proofread
Once the Proofread is ready, find it in your dashboard Projects. Inside the editor you have several tools:
Change the Speaker
If the wrong speaker was assigned or lip movements are off, click the Speaker column and select the correct speaker.
Change the Voice
Click the audio track, then go to Track section > Select Track Voices to choose a voice: your own cloned voice, a voice from the HeyGen library, or generate a new one.
💡 After changing a voice or editing a segment's text, click Refresh Voice to regenerate the audio for that segment. A yellow Refresh Voice button means that segment's audio is out of date and needs regenerating — always refresh after changing timestamps too.
Adjust the Script
Click into any segment to edit the translated text. To add a new line, click Add a Script between two timestamps, type your text, and click Update Translation — HeyGen will auto-generate the translation.
Pronunciation Respelling (Inline)
To fix how a specific word is pronounced: highlight the word → click Pronunciation → enter a phonetic respelling and click Play to hear it.
⚠️ Important: Inline pronunciation respelling applies to that one instance in that one segment only. It will not fix other occurrences of the same word in other segments. For a term that needs consistent pronunciation across the whole video, use Brand Glossary → Pronunciation instead.
Preview vs. Result
At the top of the Proofread editor you'll see two tabs:
Preview — plays the translated audio against the original video with no lip sync. Use this to check your script and voice before committing to a full render.
Result — the fully rendered video with lip sync applied. Only available after you click Generate Result.
When generating your Result, you can choose:
Include captions — burns translated subtitles into the result video.
Translate audio only (no lip sync) — generates an Audio Only result even from a Proofread project.
Working on Your Script Outside of HeyGen
You can download the Excel or SRT file of your script, edit it externally, and re-upload it to your Proofread project.
⚠️ Segment count mismatch on SRT upload: If your uploaded SRT has a different number of segments than the Proofread, it will fail to import. This happens because short neighboring segments get merged when the Proofread is built. Fix: either attach your SRT before creating the Proofread, or download the current script from the Proofread and edit that file instead of your original.
💡 Version History: Proofread now includes full version tracking. As you edit, the header shows exactly what’s saved — “Saved as version X on <date/time>” next to the save icon. Click Get Versions to see your full edit history with clear labels (e.g. “Version 3 (Auto-Saved)”, “Restored from Version 2”). Any earlier version can be restored with one click — the pre-restore state is automatically saved as its own version so nothing is ever lost.
The Result tab shows a “Version X” badge indicating which saved version your current video was generated from. If the script has changed since the last generation, a Stale badge appears — the old result stays viewable for comparison rather than being locked.
Invite Other Teammates to Edit Your Proofread
HeyGen allows you to invite teammates or contractors to help edit your Proofread.
🛎️ Business plan: Invite teammates using the "Share" button. Invitees must have a seat on your HeyGen Team plan.
Enterprise plan: Click Invite proofreaders (top right) and enter their email. Enterprise proofreaders do not consume a HeyGen seat. Invited users need a free HeyGen account to log in. Note: access is scoped to that one language version of the Proofread — not the entire project.
You can also hire professionals via our marketplace: Contra.com
While editing, you and your team can leave comments on specific words or sentences, attach images or audio notes, and tag collaborators.
Proofreading Best Practices & Troubleshooting
I'm getting a warning: "script may be too short or too long"
These are warnings, not blockers. They indicate the text doesn't perfectly fit the scene length. Click the small Play button to preview. If it sounds fine, ignore the warning. If not, slightly adjust the script or timestamps to fix the pacing.
Avoid overlapping timestamps
Overlapping timestamps will block you from submitting the Proofread. Ensure each segment ends before the next begins (e.g. if one ends at 00:00:32.740, the next must start at 00:00:32.750 or later).
Fixing Voice and Lip Sync Issues
If you encounter accent inconsistencies or lip-sync problems, extract the audio from your original video and create a Custom Voice using HeyGen's Voice Clone feature, then reapply it to your project.
Keep in mind: if a speaker's head is turned more than 30° from the camera, or appears too small in the frame, lip sync may not be perfect.
Dealing with Off-Screen Speakers and Gender Swaps
For videos with off-screen speakers (e.g. narrators), the system may accidentally lip-sync their voice to an on-screen character. To prevent this, mark those script blocks as Off-Screen in the Speaker column.
You can also correct gender swaps here — simply reassign the correct voice to the correct speaker from the voice library.
Script and Speed Adjustments
Click Add a Script between timestamps to insert a new line. Type your text and click Update Translation. HeyGen will auto-generate the translation.
