Polotno SDK lets you embed a complete text editing system inside your app. Users can type, style, and format text directly on the same canvas used for images, shapes, or video, all powered by a unified schema. Developers can offer advanced typography, alignment, and formatting controls without relying on external editors or third-party fonts.
Everything runs in the browser or on your own servers, ensuring full control over user data and UX. Text elements are defined in the text element schema, which exposes every property (font, color, alignment, spacing, and transformations) for precise programmatic control and automation.
Key features
Fonts and typography
Support for system and custom fonts with dynamic sizing, weights, and colors. Define consistent type hierarchies for templates or branded content, or let users freely customize font families, letter spacing, and color schemes. Weight is numeric, not a bold on/off toggle: set 300, 500, or 700 on a selection and the matching Google font variant loads on demand, so only the weights actually used are fetched.
Rich text editing
Allow inline formatting, all editable directly on the canvas. Formatting is per span rather than per element: bold, italic, underline, strike-through, color, and both font family and font size can differ inside a single text element. Developers can combine spans with different properties, giving users fine control over captions, headings, or multi-style layouts. The rich text API exposes the same controls to a custom toolbar.
Text alignment and spacing
Control horizontal and vertical alignment, line height, and letter spacing at both template and element level. These adjustments are live and non-destructive, enabling precise design without external layout tools.
Curved and transformed text
Create curved text paths and rotated text blocks for more flexible layouts. The schema supports geometric transformations like rotation, scaling, and positioning so developers can enable creative typography effects programmatically or interactively.
Text effects
Strokes with a configurable line join (round, miter, or bevel), shadows, and gradient fills that stay correct on rotated, curved, and stroked text. Highlight backgrounds render as a per-line polygon, the Instagram-style look, and follow the same geometry in SVG and HTML export.
Lists, scripts, and direction
Real bullet and numbered lists with markers that sit where the canvas draws them. Subscript and superscript survive editing, as do tab characters. Right-to-left text gets the correct base direction on canvas and in every exporter, so trailing punctuation, alignment, and mixed-script lines match what the user saw.
Fitting text to a box
Text does not have to overflow its frame. Choose whether it resizes its box, shrinks its font, or truncates with an ellipsis, set a placeholder for empty text, and let the box grow or clamp as content changes. This is what keeps data-driven templates intact when a product name runs long. See text overflow and vertical text resize.
Automation and schema control
Every property (font, color, alignment, text content, spacing, and transformations) is defined in the text element schema. Use the schema to generate, edit, or update text programmatically, integrate with AI systems, or build automation pipelines for personalized templates at scale.
Example use cases
- Ad builders – Generate dynamic text layouts for personalized marketing templates.
- AI content platforms – Combine AI-generated copy with predefined typography styles.
- E-commerce platforms – Let merchants create product cards or labels with on-brand text styles.
- Social media tools – Enable quick captioning, branding, or text overlays on media assets.
- Print and signage systems – Create precise typographic layouts for packaging or large-format prints.
- Internal creative hubs – Standardize typography across departments with custom font presets and locked styles.
- Creative automation systems – Generate thousands of text variations automatically using the schema and rendering API.
Developer benefits
- Unified engine for text, image, and video editing.
- Self-hosted by default, cloud-ready for automation.
- Schema-driven architecture for automation and reproducibility.
- Full control over fonts, rendering, and template logic.
- Commercial-safe licensing for SaaS and enterprise products.
FAQs
Can I use custom fonts?
Yes. You can load and register any web-safe or custom font files directly in the SDK.
Does it support multi-style or partial formatting?
Yes. The rich text system supports multiple styles within one element, including different font families and font sizes inside the same text block.
Can I set a specific font weight rather than just bold?
Yes. Font weight is numeric, so a selection can be set to 300, 500, 700, or any weight the family publishes.
Does text handle right-to-left languages?
Yes. RTL base direction is applied on the canvas and carried through PDF, SVG, HTML, and PPTX export.
Can I automate text updates?
Absolutely. Every text property is accessible through the JSON schema for programmatic modification.
Can I mix text with images and videos?
Yes. Text, image, and video elements all share the same schema and canvas.
Is it possible to self-host?
Yes. The editor runs client-side or on your infrastructure for full privacy and performance control.
