Polotno is an image editing API and an image editor SDK in one package. Users can upload, crop, mask, and manipulate images directly on the same canvas used for text, shapes, or video, while your backend calls the same schema to manipulate images from code. The SDK supports raster and vector workflows, including SVG, giving developers full flexibility for creative applications or automation systems.
Everything runs client-side or on your own servers, providing complete control over user data, UX, and performance. Image elements are defined in the image element schema, and scalable graphics through the SVG element schema. Both expose parameters like position, scaling, masking, and opacity, enabling precise, programmatic control over any visual layer.
Key features
Upload and placement
Users can upload JPG, PNG, WebP, or SVG files and place them directly on the canvas, no server upload required. The same operation is available from the API: pass an image URL or base64 data into the schema and it appears on the canvas exactly as if a user had uploaded it.
Cropping and resizing
Crop or scale images interactively in the editor, or set the crop region directly from code. Both paths write the same schema properties, so a crop applied by a user and a crop applied by code are indistinguishable, and both are recorded for reproducibility and automation.
Masking and transparency
Apply shape masks to any image layer in the editor, or fade it with an editable linear or radial opacity gradient, positioned with handles on the canvas and layered over any mask already applied; the fade lives in the effects panel. From code, apply a clipping mask, built-in shapes or a custom SVG, for automated cutouts across a whole batch of images.
Filters and adjustments
Modify brightness, blur, contrast, saturation, or opacity directly through the API or UI controls. Adjustments are non-destructive and can be stored as schema properties for reapplication or batch processing.
Shadows, borders, and corners
Add a drop shadow (blur, offset, color, and opacity are each independently controllable), a solid border, rounded corners, or a horizontal or vertical flip, to any image. Each is its own schema property, so a batch job can apply the same border and corner radius across thousands of images in one pass.
Export and output
Export the edited image to PNG, JPEG, PDF, SVG, or the underlying JSON itself, either directly from the browser or through the Cloud Render API for server-side and batch jobs. JSON export means the manipulated result is also a document you can re-import, diff, or store, not just a flattened pixel output.
SVG and vector elements
Polotno supports SVG files as first-class elements through the SVG element schema. Developers can manipulate vector shapes programmatically (change paths, fill colors, stroke widths, or apply transformations) enabling hybrid raster/vector designs and dynamic iconography.
Automation and schema control
Every image and vector property (source, size, mask, rotation, opacity, and filter) is accessible through the schema. Use this for automated template generation, AI-assisted layouts, or bulk creative production.
Pairing with an AI image generation API
An AI image generation API (OpenAI, Gemini, Stability, or any provider you already use) produces a starting image. It doesn't crop it to a template, add your logo, lay text over it, or batch-produce variants, that's a separate job. Polotno's image editing API is built to sit right after generation in that pipeline: drop a generated image onto the canvas as any other image element, then crop, mask, filter, and manipulate it the same way, by hand in the editor or by code through the schema. Bring your own AI provider and key; Polotno doesn't require routing generation through its own servers. See AI and data integration for how this connects to the wider automation schema.
What you can do with an image manipulation API
These are the schema operations behind that image manipulation API in practice:
- Crop and resize to a fixed template dimension, freeform or aspect-locked.
- Mask and cut out a subject using built-in shapes or a custom SVG path.
- Recolor and adjust brightness, contrast, saturation, and opacity, non-destructively, so the original stays intact.
- Replace backgrounds on a generated or uploaded image, then layer text and brand elements on top.
- Batch-manipulate hundreds of images from one template by swapping the source image in the schema and re-rendering.
- Convert and export the finished image to PNG, JPEG, PDF, SVG, or JSON, locally or through the Cloud Render API.
Example use cases
- Marketing and ad builders – Automate ad template generation using images, SVGs, and brand assets.
- AI design tools – Combine generated visuals or logos with programmatic filters and transformations.
- E-commerce platforms – Let sellers create product visuals, banners, or print designs directly in-app.
- Print and signage systems – Handle both raster and vector workflows for packaging or large-format output.
- Photo personalization apps – Enable background replacement, masking, and quick adjustments for user-generated content.
- Creative automation systems – Generate thousands of visual variants programmatically via the schema and cloud rendering API.
- Internal creative tools – Let teams produce consistent, on-brand graphics inside private systems.
Developer benefits
- Unified canvas for images, text, SVG, and video.
- Self-hosted by default, cloud-ready when needed.
- Schema-based architecture for automation and reproducibility.
- Native support for both raster and vector formats.
- Commercial-safe licensing for SaaS and enterprise integrations.
FAQs
Is this an image editing API, an image editor SDK, or both?
Both, in one product. The image editor SDK is the embeddable UI, the canvas, panels, and controls your users interact with. The image editing API is the same schema accessed from code, for cropping, masking, or manipulating images without opening the editor. Use either on its own, or together.
Can I use this alongside an AI image generation API like OpenAI or Gemini?
Yes. Generate the image with whatever provider you already use, then load it into Polotno as a normal image element to crop, mask, template, and export it. Polotno doesn't generate images itself and doesn't require routing your AI calls through its servers.
Is this an image manipulation API?
Yes. Polotno works as an image manipulation API: cropping, masking, filtering, recoloring, adding shadows or borders, and batch-replacing source images are all schema operations you can call from code, not just UI actions.
Which image formats are supported?
For upload, JPG, PNG, WebP, and SVG are supported out of the box. For export, the edited result can be output as PNG, JPEG, PDF, SVG, or JSON.
Can I automate image updates or replacements?
Yes. Every image property is defined in the schema and can be modified programmatically.
Does Polotno support SVG manipulation?
Yes. The SVG element schema enables path, fill, and transformation control for vector graphics.
Can users mix raster images and SVGs?
Yes. Both coexist on the same canvas with unified positioning, scaling, and masking controls.
Is self-hosting possible?
Yes. The SDK runs fully client-side or on your infrastructure for privacy and performance.
