HTML Widget
The HTML Widget runs your own HTML, CSS, and JavaScript as a widget on the mobile Dashboard, connected to your datastreams. It is the same widget as in Console and it uses the same BlynkBridge API described in HTML Widget Developer Guide, so a widget built for the web Dashboard runs in the App without changes to its code.
The App loads the widget's .html file from Assets and injects BlynkBridge before your page scripts run. Through it your page can read datastream values, write values back to the Device, receive real-time updates, read Device metadata, fetch historical and map data, pick up the app theme, and open other pages.
Adding an HTML Widget
Switch to Developer Mode and open the Template's mobile device dashboard in the Mobile Dashboard Editor.
Add the HTML Widget to the dashboard.
Open the widget settings.
Choose an HTML file: Blynk preset, uploaded assets, or import file from your phone.
Assign datastreams, add pages if your widget navigates.
Save widget.
Widget settings
The settings screen has four sections.
Preview
Renders the selected file with the current settings
Datastreams
The datastreams the widget can read and write
Pages
The dashboard pages the widget is allowed to open
HTML File
The .html file the widget renders
Datastreams
Each datastream is accessible in your HTML code by its index, shown on the left of the row. The order of rows defines the index, starting at 0 — your code refers to datastreams by that index, not by name.
Note: Reordering or removing a datastream changes the indexes of the ones after it. If your widget reads by index, check it still points at the right stream after editing this list.
Pages
Pages lists the dashboard pages this widget can open, numbered from 0. Your code opens them by that index with showPage(index) — not by page ID.
Tap Add page to add a target. See Pages for how dashboard pages work.
HTML File
Shows the folder and file name of the selected file, for example WIDGET LIBRARY / DISPLAY → Value label.html. From here you can:
Choose another — reopens the Choose HTML File screen
Clear selection — unassigns the file and returns the section to its empty state
Choosing an HTML File
The Choose HTML File screen is where you pick the file the widget renders.
My files
Lists only .html files stored in the Widget Library folder in Assets or its sub-folders. Files kept elsewhere in Assets are not shown.
Presets
Ready-made widgets built and maintained by Blynk. When you select a preset and confirm, a copy is created in Widget Library → My widgets — the same behavior as on the web. The original preset is never modified.
Importing from your phone
The upload button in the header opens your phone's file picker so you can import an .html file from the device. The imported file is added to your Assets.
Tip: Sub-folders inside Widget Library appear as separate groups here. Organize your widgets into sub-folders in Console and the App's list follows the same structure.
Generating widgets with AI
Blynk publishes blynk-html-widget, an Agent Skill that teaches an AI coding agent how to build HTML widgets. It carries the BlynkBridge API reference, the platform constraints, and Blynk's visual style, so the agent produces a widget that works instead of guessing at the bridge.
Download the skill and follow the steps in Generating widgets with AI. Generate and edit the widget in Console, then select its .html file in the App.
Limits
The HTML widget is available on all plans. The number of widgets you can add differs by subscription.
HTML code size
100,000 characters per widget
HTML Widgets per Template
1,3,10,20 per plan — see Blynk pricing
Historical data range
Maximum 365 days per request
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