CEP to UXP Migration Guide for Adobe Plugin Developers

Adobe's shift from Common Extensibility Platform (CEP) to Unified Extensibility Platform (UXP) is the most significant change to plugin development in a decade. If you're maintaining a CEP-based extension, here's what you need to know — and why rushing to migrate might be a mistake.

Why Adobe Is Killing CEP

CEP was built on Chromium Embedded Framework — essentially, each panel ran as a full Chrome browser instance. This architectural choice had consequences:

Memory bloat: A single panel could consume 200-500 MB RAM
Slow startup: Loading HTML/CSS/JS through Chromium added 2-3 seconds per panel
Security risks: Full Node.js access meant malicious plugins could wreak havoc

For creative apps already pushing hardware limits (looking at you, After Effects), this was unsustainable. Enter UXP.

UXP: Faster, Lighter, More Restrictive

UXP replaces Chromium with a native JavaScript engine. The benefits are immediate:

~70% reduction in memory usage
Instant panel loading
Consistent UI (Adobe Spectrum Design)

But there's a catch: UXP is far more restrictive. Features that were trivial in CEP now require workarounds or are impossible.

What You Lose in UXP

Arbitrary file system access: Users must manually grant folder permissions
External libraries: No npm modules that rely on Node.js internals
Advanced networking: WebSocket support is limited
DOM manipulation freedom: Must use Adobe's Spectrum components

            Critical Reality Check: Some advanced features (like Premiere Pro's Export Controller API)
            still require CEP or C++ plugins. UXP can't access everything yet.
        

When to Migrate vs. When to Wait

Migrate to UXP If:

Your plugin is UI-focused (color pickers, asset browsers)
Performance complaints are common (users report lag)
You target Photoshop or XD (UXP-native apps)

Stick with CEP (For Now) If:

You need deep file system integration (media asset management)
Your plugin relies on specific Node.js modules
You're targeting Premiere Pro's export pipeline

The Hybrid Approach (Our Recommendation)

The smartest strategy for complex plugins: UXP for UI, C++ for backend.

Here's how it works:

Build your panel UI in UXP (fast, lightweight)
Write performance-critical logic in C++ as a native plugin
Communicate between them via Adobe's scripting bridge

            // UXP Panel (JavaScript)
            const { entrypoints } = require("uxp");

            entrypoints.setup({
            plugin: {
            create() {
            // Call C++ plugin via ExtendScript
            const result = app.executeScript("MyCppPlugin.processVideo()");
            console.log("C++ returned:", result);
            }
            }
            });
        

This gives you UXP's performance benefits while bypassing its limitations. Kreative Core's Vision plugin uses this exact architecture.

File System Access: The Biggest Pain Point

In CEP, you could read/write anywhere:

            // CEP (Old Way)
            const fs = require('fs');
            fs.writeFileSync('/Users/editor/Desktop/export.json', data);
        

In UXP, users must grant explicit permission:

            // UXP (New Way)
            const { localFileSystem } = require("uxp").storage;

            async function saveFile() {
            const folder = await localFileSystem.getFolder(); // User picks folder
            const file = await folder.createFile("export.json");
            await file.write(data);
            }
        

This adds friction but improves security. Power users appreciate the control.

UI Changes: Spectrum or Bust

CEP let you use any CSS framework (Bootstrap, Tailwind, custom). UXP enforces Adobe Spectrum:

            <sp-button variant="cta">Process Footage</sp-button>
            <sp-slider min="0" max="100" value="50"></sp-slider>
        

Pro: Your plugin looks native.
Con: Less design freedom.

For SaaS-like plugins (where brand identity matters), this can be limiting. But for utility tools, Spectrum is perfect.

Migration Timeline: Plan for 6-12 Months

Here's a realistic migration path:

Month 1-2: Audit current codebase. Identify UXP blockers.
Month 3-4: Build prototype UI in UXP. Test performance gains.
Month 5-6: Migrate core logic. Write C++ modules if needed.
Month 7-10: Beta testing with power users. Fix edge cases.
Month 11-12: Public release. Maintain CEP version for legacy users.

            Don't Rush: Adobe still supports CEP. Premiere Pro 2025 runs CEP panels perfectly. Migrate
            when UXP truly benefits your users, not just to chase the new platform.
        

Our Experience: Kreative Core Vision

When building Vision, we initially tried pure UXP. We hit walls immediately:

Needed GPU access for ONNX inference (impossible in UXP)
Required deep frame export control (CEP-only API)
Wanted background processing (UXP panels pause when hidden)

Solution: UXP panel + Node.js backend running as a separate process. Best of both worlds.

Key Takeaways

UXP is the future, but CEP isn't dead yet
Hybrid (UXP + C++) is the best architecture for complex plugins
Migrating blindly can break critical features — audit first
Users care about performance and reliability, not platform buzzwords

CEP to UXP Migration: What Plugin Developers Need to Know