Using VisualizerApp with confidence

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VisualizerApp is for teachers, tutors and teaching staff to operate. Students should not use the app, including Phone Camera.

1. Open VisualizerApp v3. Chrome is the primary tested browser; current Edge, Firefox and Safari builds may also work.
2. Use the Start camera button as needed and allow camera access when the browser asks.
3. If the laptop camera opens instead of a connected document camera, open the left menu, expand Hardware, and choose the correct camera in the Camera drop-down box.
4. Move the camera over a worksheet, book or object, then adjust the stand and room lighting before relying on digital zoom.
5. For an on-screen walk-through, open the left menu and choose Interactive Tutorial.

Camera and view controls

Open the left menu for Visual Settings, Image Profiles and Hardware. You can adjust zoom, brightness, contrast, sharpness, rotation, mirror/flip, keystone, aspect ratio, resolution and camera device where the browser and hardware support them.

Default and Document Scan are Free camera profiles. Pro adds Whiteboard, Blackboard, Object / Demo, Low Vision, Art / Colour, Book Reading and Science Close-up. Results still depend on the physical camera and lighting.

Split view places live and frozen views together. Hardware also contains Camera PiP for a floating view of the current camera and Second Camera PiP for a second connected camera, where the browser and devices support them. Fullscreen hides browser distraction where permitted.

There is a simpler Classic theme in the v3 version of the app. Look for the appearance option in Settings → General; it does not switch to the older Classic app.

Freeze frames and annotations

Select the pause button or press Space to freeze the current view. VisualizerApp keeps up to eight session frames on Free and 16 on Pro; the oldest frame is replaced when the limit is reached. Use the left and right arrow keys to move through saved session frames.

Open annotation with the pen button or A. Core tools include Pen, Highlighter, Text, Line, Arrow, Rectangle, Ellipse, Triangle, Diamond, Pentagon, Hexagon, Star and Callout. Text is placed where you click; type in the pop-up, use A−/A+ to size it, then press Enter to place it.

Frozen-frame annotations are saved into that frame automatically. Undo reverses the most recent annotation change; Clear removes all annotations from the current frame. Save image creates a PNG. Frozen-frame tools can also add a label, written teacher note, tags, audio teacher notes Experimental, and text recognition Experimental with read-aloud where supported. Text recognition offers separate Printed text and Handwriting scans. Handwriting mode has a large first-use download for its models and recognition engine after opening or updating the app, runs in a background browser worker, and works best with large, dark, well-spaced writing. Joined or faint writing can still be wrong or missed. Audio-note support varies by browser. Play back audio, and always review and correct the editable recognised text before relying on either feature.

The Free Transparent Overlay places the current full frozen frame over the live feed at adjustable opacity; it requires full frozen view and is unavailable in split view. It is separate from the Pro Comparison Overlay, which accepts other image sources and can be repositioned, scaled and corner-aligned.

Grid choices include Rule of Thirds, 4×4, Crosshair + Margins, Graph Paper, Dot Grid and Math Axes, with three sizes. Free measuring tools include Ruler and Measuring Line; Pro adds Protractor, Angle, Compass Circle and Set Square. Some measuring controls are hidden on narrower screens.

Use a phone as the camera

1. On the computer, open the left menu and choose Phone Camera near the top.
2. Scan the QR code with the phone within two minutes. Choose Start camera on the phone and allow camera access for a local preview. Check that the same four-digit code appears on both devices, then approve the phone on the computer within 30 seconds to start sharing.
3. On the phone, choose Data saver, Standard (recommended) or High (strong connection). High uses more battery and data and may not be available on every phone.
4. When the camera is ready, the phone automatically switches to a compact camera view so that most of the preview stays visible. Show live feed on computer returns both the computer and an open Presenter window to the single live phone view. Capture example and Stop sharing camera remain available in the compact view.
5. Use Capture example and Undo last capture for up to four pupil-work examples. Captures are Free and become frozen frames in the computer browser; Done – show comparison uses the Pro Student Work layout in Presenter Mode. Choose More controls to restore the full phone panel and Camera view to collapse it again.
6. When finished, choose Stop sharing camera on the phone. This intentionally ends Phone Camera mode on the computer; choose Start camera there to use its local camera.

If Wi-Fi or mobile data drops briefly, leave both pages open while they show a reconnecting state; the app has up to one minute to resume the same approved session, then stops the camera and requires a new pairing. The full phone controls reopen if attention is needed. Stop sharing camera is for ending the session, not a temporary interruption.

PeerJS signalling and public STUN services establish the encrypted WebRTC link; live media then travels directly between the approved devices. Phone Camera works best when both devices use the same reliable Wi-Fi, but they do not have to share a local network. School firewalls, VPNs or restrictive networks can block the STUN-only connection.

Timer, spotlight and reading aids

Open Timer from the toolbar or press T. It opens at one minute, with 1, 2, 3, 5, 10 and 15 minute presets. Start, pause and reset the countdown; choose an end sound or background music, whether it appears over the camera, and whether the timer bar is shown. Pro adds custom minute/second input, dragging and a full-screen timer.

Spotlight darkens the view around the pointer and can be toggled with S. Highlight Strip and Masking are Free; Pro adds Snip and Magnifier. Settings panels remain usable without intentionally cancelling the active mask.

The Free Extra tools menu includes Random Name Picker, Spinner, Tally Mode, Word Cloud, QR Code Display, Spotlight / Mask, Birthday Mode, Celebration Mode and Sound Meter. The floating Pro Tools button groups presentation, comparison and extended classroom tools in one movable panel.

Resource Pane, books and local PDFs

The Resource Pane has four areas: Pinned, Search Resources, Upload PDF and History. Pin a useful website or result, search supported book/audiobook and fact sources, or open a PDF from the device.

Resource search can use VisualizerApp's Cloudflare proxy, Open Library/Internet Archive, Wikidata and external DuckDuckGo search. Opening a result sends the search or request information to the relevant provider. Local PDFs are rendered in the browser, but the first use may need to download the PDF library.

Rights and availability vary by item. Some books can display inside the app; borrow-restricted or unsupported items open in the Internet Archive reader or provider website.

Build reusable lessons with Lesson Decks

Lesson Decks store frozen camera frames and their annotations, with optional overview and agenda text, visible resource shortcuts, notes, tags, text-recognition results Experimental, audio notes Experimental, camera setup, timer preset and Comparison Overlay.

1. Freeze and annotate the screen or screens you want to reuse, then open Lesson Decks from the left menu.
2. Add a title and, if useful, an overview or agenda. Select the optional content to include.
3. Choose Save Frame to save only the currently selected frozen frame as a deck, or Save Deck to save all current frozen frames.
4. Clear current frozen frames after Save Deck is selected by default. Untick it before saving if those session frames should remain open.
5. Use My decks to search titles, overviews and tags, filter by tag, sort the library, or select several decks for export.
6. Select a saved item to preview, export, replace or delete it. Open Deck replaces all current frozen frames with the saved deck's frames; it does not merge the two sets. VisualizerApp warns first when the current session has unsaved changes.

Text recognition can be incomplete or incorrect, and audio support varies by browser and device. Check recognised text and play an audio note before relying on or exporting either feature.

Free can keep two saved decks. Pro removes the plan limit and can maintain a large local library, subject to a 250-deck and 500 MB per-browser safety allowance. The storage meter warns as the allowance fills. Export selected decks in smaller batches when a library becomes large.

Use Export deck for one reusable .vadeck file, Select decks to export a chosen group, or Back up decks for the whole library when it fits within the 50 MB backup-file safeguard. The reminder recognises successful individual and selected-deck exports, so a larger library can be covered in safe batches. Imported name clashes are kept as separate copies, and importing an all-app backup adds its decks as safe copies instead of replacing local decks. Pro can also export a deck as PPTX in Full slide, 2-up or 4-up layout. Choose Slides only (no notes or audio) for frame images, any available saved Comparison Overlay, annotations and labels without the overview, agenda, teacher notes, text-recognition results or audio. Alternatively, include those details in speaker notes or a visible text box. Exporting does not change the saved deck.

Decks are stored locally in this browser. Recoverable current-session drafts are local too, and both can be lost if its site data is cleared or the device/browser profile changes. After an interrupted session, open Lesson Decks and choose Recover draft when it appears. Use Settings → Backup for a manual all-app backup.

Presenter Mode and Comparison Overlay Pro

Presenter Mode opens a clean output window for a projector or screen share. It supports live, freeze, white and board scenes, scene-specific drawing, spotlight/trail pointer, frame navigation, Student Work layouts and labelled captures. Allow pop-ups for VisualizerApp before opening it.

Student Work can show saved frames from a laptop or USB camera as well as a paired phone. Freeze saves a frame; the main window's C capture shortcut saves a frame and downloads a PNG while leaving the current view in place. Use the arrows to move between pages of four. Presenter pointers act only in the window containing the mouse; leaving the image or switching windows clears their temporary trail or spotlight.

The Pro Comparison Overlay is separate from the Free Transparent Overlay. It can use an uploaded image, pinned resource, frozen frame, direct image URL or built-in template. Adjust opacity, position, scale and corner alignment, then save the setup with a Lesson Deck where supported.

On the main window, hold Ctrl+Alt with 1–4 for scenes, 5 for layout, M for pointer, L for lock, H for help, D for the deck, R for the reveal mask, or Left/Right for deck navigation. The presenter window also shows its own shortcut help.

Recording and export

Use Record or press R. Free recording supports up to two minutes plus a 20-second loop option. Pro extends normal recording to five minutes and adds longer loop presets. Browser codec support and device performance affect the output.

Free can save a watermarked annotated PNG and use one PDF export per app session with a VisualizerApp footer. Pro removes the PDF and PNG watermark, adds unlimited Current and All PDF export, bulk All PNG download and PowerPoint Lesson Deck export. Current PDF exports the current camera or frozen composition, including the visible Comparison Overlay, annotations and supported visual effects. All PDF and All PNG apply the visible active Comparison Overlay to each frozen frame. PowerPoint uses any available Comparison Overlay saved with the selected Lesson Deck, or the visible active overlay when exporting the current frozen frames. The overlay is flattened beneath annotations; adjustment handles and app controls are not included, and exporting does not change the original frames or deck. Frame labels are supported in PDF and PowerPoint output; the bulk PNG download contains the frame images without labels.

The 24-hour Pro Preview is available once per browser in any 90-day period, starts inside the app and needs no key, email or card. The separate 7-day Pro Free Trial is issued by email through Lemon Squeezy and also needs no payment card.

Settings, activation, backup and offline use

Analytics settings: Google Analytics runs only if you allow it in Analytics settings. In v3, open Settings > General > Analytics and privacy, or use Analytics settings in the website footer, to review your choice. A fresh opt-in is required for this notice. Analytics measures consenting teachers' use of tools, not camera media, pupil work or lesson content. Declining or withdrawing does not remove features or saved work. Read the privacy information.

Settings contains General, Branding, Backup, Tips, What's New and Activation. General includes Free Last Setup, while Pro adds a separate Saved Setup. School branding is Pro. Pro Tools also includes A/B/C presets and stop-motion interval capture from 1 to 15 seconds. Activation shows licence status and expiry details after a key is active.

When installation is supported, choose Install App near the bottom of the left menu or under Settings → General, in Performance and recording, then follow the browser instructions. After a successful first online load or installation, supported core files may remain available from browser cache. Offline availability varies, so test it before a lesson.

Phone pairing, resource search, activation/revalidation, handwriting-model setup, and the first loading of some OCR, PDF or PowerPoint libraries need an internet connection.

Main keyboard shortcuts

Troubleshooting

The camera is blank or denied

Check the camera icon in the browser address bar, allow access for visualizerapp.com, close other apps using the camera, then reload. On a managed device, ask the administrator whether browser camera access is blocked.

The wrong camera opened

Open Hardware and choose the camera by name. Disconnect/reconnect a USB camera if it is missing. Set Resolution and Aspect to Default while diagnosing.

The video is slow

Choose a lower resolution or Phone Camera quality, close other video tabs, and use Settings → General → Performance and recording. High-resolution capture, experimental text recognition and effects need more memory and graphics performance.

Phone Camera will not connect

Keep the pairing screen open, approve the matching four-digit code within 30 seconds, try the same Wi-Fi without a VPN, and ask whether the school network blocks WebRTC/STUN. Refresh both devices to create a new QR code. If an approved stream drops briefly, leave both pages open while the reconnect attempt runs.

Still stuck?

Open Feedback/Bug? from the left menu or use the Contact page. Include browser/OS, camera model, selected Resolution/Aspect or phone quality, build number, and the exact error. Do not send pupil images unless necessary and permitted.