Most code editors today are impressive… but also huge.
They ship with dozens of features, plugins, telemetry layers, web engines, background services, and sometimes feel closer to a browser than a native tool. That’s not necessarily bad — but I wanted something different.
I wanted a code editor that feels:
- instant
- small
- native
- focused
- and especially fast for C++ workflows
That’s why I started Nebula, a lightweight C++ code editor with a strong focus on rendering performance, clean architecture, and a minimal but modern feature set.
In this article, I’ll share what I built, what I learned, and what changed recently — including dynamic theme support and drag & drop.
Why build a new editor in 2026?
This is the obvious question.
The honest answer:
I didn’t build Nebula because there aren’t enough editors. I built it because:
1) I wanted full control over performance
I wanted to measure and optimize everything: startup time, memory, UI redraw cost, text rendering speed.
2) I wanted a native architecture
No webview. No Electron. No huge runtime.
3) I wanted something simple
A fast editor that does the core job well:
open files, edit, search, syntax highlight, manage projects.
Goals and constraints
Before writing any code, I defined a few hard constraints:
- Small binary
- Low memory usage
- Fast startup
- Smooth scrolling even with large files
- Clean UI
- No plugin system (for now)
- No dependency explosion
This is a different mindset than “add features until it becomes a full IDE”.
Architecture overview
Nebula is built around a few main layers:
Core layers
- UI layer (windows, panels, tabs, layout)
- Editor layer (text buffer, selection, cursor, undo/redo)
- Rendering layer (glyph drawing, caching, clipping)
- File & project layer (open/save, tree, recent files)
- Settings layer (including the new dynamic theme system)
The key idea:
Nebula is not “a single editor widget”.
It’s a set of small modules that communicate with simple data structures and events.
Rendering: where everything matters
Text editors look simple until you try to render them fast.
Rendering is the heart of Nebula, and most performance lessons came from this part.
The main issues
- Rendering thousands of glyphs every frame is expensive
- Measuring text layout is expensive
- Scrolling causes constant redraw
- Syntax highlighting adds CPU cost
- UI animations and resizing can destroy frame stability
The approach
Nebula uses a rendering pipeline that tries to:
- avoid re-measuring text constantly
- reuse cached glyph data when possible
- redraw only what’s needed
- keep the UI responsive under load
The goal is not “maximum features”.
It’s maximum responsiveness.
The editor core: text buffer design
The text buffer is another big piece.
A naive implementation (like a big std::string with insert/delete) becomes slow quickly when editing large files.
Nebula uses a buffer design that keeps operations like:
- insert
- delete
- selection edits
- multi-line operations
fast enough for real work.
Even if you don’t notice it directly, the editor “feel” comes from that.
Syntax highlighting: keep it fast
Syntax highlighting is one of the easiest ways to kill performance.
The biggest mistake is re-highlighting the entire file on every keypress.
Nebula does incremental updates:
- highlight only impacted lines
- avoid expensive parsing on every edit
- cache results where possible
The goal is:
you should never feel the highlighter.
Recent update: Dynamic theme system
This is one of the biggest recent improvements.
Previously, the editor had a more static style configuration.
Now Nebula supports dynamic themes, meaning:
- theme changes apply instantly
- UI + editor colors update live
- no restart required
- themes can be extended more easily
Why it matters
A theme is not just “colors”.
It impacts:
- readability
- focus
- perceived quality
- and user comfort during long sessions
Also:
Users expect themes. Even minimal tools need this in 2026.
Recent update: Drag & Drop support 🖱️
Nebula now supports drag & drop, which seems simple, but required several design decisions.
What it enables
- drag a file into the editor to open it
- drag multiple files
- drag folders (optional, depending on OS behavior)
- smoother workflow, especially for quick edits
Why it was harder than expected
Drag & drop touches:
- OS events
- window focus
- file path validation
- tab management
- project behavior
This feature is a good example of something that looks small but affects many layers.
Lessons learned from building Nebula
1) Performance is architecture
If you “optimize later”, you often end up rewriting.
A fast editor is fast because it was designed to be fast.
2) Every feature has a hidden cost
Drag & drop is not just “open file”.
Themes are not just “change colors”.
Even small features create complexity in:
- settings
- rendering
- event handling
- edge cases
3) Smoothness is more important than raw speed
Users don’t measure your milliseconds.
They feel:
- stutter
- lag
- UI delays
- slow scrolling
The main goal is consistency.
Why Nebula stays minimal (for now)
I could add:
- full LSP integration
- debugger
- extensions
- Git UI
- terminal
- build system
But the more you add, the more you risk turning it into the thing you tried to avoid.
Nebula is intentionally a focused tool:
fast editing, clean UI, low overhead.
What’s next?
Some ideas on my roadmap:
- improving large-file performance even more
- better project indexing
- smarter search
- more themes / theme import
- refining the UI layout system
But the most important goal stays the same:
Make a lightweight editor that feels instant.
Try Nebula
Nebula is available here:
https://astracode.dev/
If you try it and have feedback (bugs, UX, performance), I’m open to it — especially from people who care about native software and fast tools.
Final thought
Building a code editor is one of the best ways to learn about:
- performance
- rendering
- UI architecture
- text systems
- and how small decisions scale into big problems
Nebula started as a personal project.
Now it’s becoming a real tool — and every update teaches me something new.
Top comments (3)
hi
This is very cool project !
Thanks!