📊 Two Weeks In: How My First Flutter Chart Package Is Performing on pub.dev 🚀

Rahul Prajapati — Sun, 25 Jan 2026 10:42:14 +0000

A couple of weeks ago, I published my first Flutter package on pub.dev:

👉 imp_trading_chart

It wasn’t just “another package release” — it was the result of 2 weeks of continuous brainstorming, refactoring, learning Flutter internals, and performance tuning.

Now that the package has been live for some time, I wanted to share:

📈 How it’s performing
🧠 What I learned
🤝 Where I need community help next

📦 Package Performance (Early Stage)

For a first public package, the response has been honestly motivating:

📥 Steady downloads on pub.dev
⭐ GitHub stars & watchers starting to grow
💬 Feedback and curiosity from Flutter devs interested in:
- CustomPainter
- Rendering performance
- Trading / FinTech UIs

This validated one thing for me 👇
People do care about performance-first Flutter solutions.

🧠 What I Learned Building This

This package taught me more than any tutorial or course ever could.

Key takeaways:

🔥 CustomPainter is insanely powerful when used correctly
🧩 Widget-per-candle is a performance trap for large datasets
🧠 Viewport-based rendering = massive performance wins
⚙️ Engine-first design makes future features easier, not harder
🐛 Profiling & fixing jank teaches you real Flutter

Most importantly:
Writing something others can use forces you to write better code.

⚡ What the Package Does (Quick Recap)

imp_trading_chart is a high-performance trading chart engine for Flutter, inspired by TradingView Lightweight Charts.

Core highlights:

⚡ CustomPainter-based rendering (no widget-heavy charts)
🧠 Viewport-driven drawing (only visible candles rendered)
📊 Handles 10k+ candles smoothly
🔄 Optimized for real-time price updates
✋ Smooth pan & zoom interactions
🧩 Clean architecture: Data → Engine → Rendering
🎨 Multiple variants: Trading, Simple, Compact, Minimal

Built for FinTech, Crypto, and Trading apps where performance actually matters.

🙌 Open Source = Open for Contribution

I’m now actively preparing the next version to make the project more contribution-friendly.

I’d love help with:

📈 Indicators (MA, EMA, VWAP, RSI, etc.)
🎛️ Public controller APIs
🧪 Stress testing & edge cases
📚 Docs, examples, and feedback
💡 Architectural suggestions

If you enjoy:

Flutter internals
Rendering pipelines
Performance optimization
Charting or trading UIs

👉 You’ll feel right at home here.

🔗 Links

📦 pub.dev: https://pub.dev/packages/imp_trading_chart
💻 GitHub: https://github.com/rahul-cse-25/imp_trading_chart

If you find it useful:

⭐ Star the repo
🧪 Try it out
💬 Open an issue
🔀 Submit a PR

I Built a High-Performance Trading Chart Engine in Flutter (and Open-Sourced It)

Rahul Prajapati — Wed, 14 Jan 2026 11:54:33 +0000

For the last two weeks, I went down a deep rabbit hole.

Not tutorials.
Not UI polish.
But how trading charts actually work under the hood.

The result of that continuous curiosity, experimentation, and learning is my open‑source Flutter package:
👉 imp_trading_chart — a high‑performance trading chart engine for Flutter
📦 Available on pub.dev

This post is about why I built it, how it works internally, and how you can contribute.

🤔 The Problem with Most Flutter Chart Libraries

Most chart libraries in Flutter are built like this:

One widget per candle
Deep widget trees
Rebuilds on every data update
DateTime calculations inside the render loop

This approach works… until it doesn’t.

Once you try:

5k–10k+ candles
Real‑time price updates
Smooth pan & pinch‑to‑zoom

You start seeing:

Jank
Dropped frames
Laggy gestures

That’s when I asked myself:

What if charts were built like engines instead of widgets?

🧠 The Idea: Engine‑First Charts

I stopped thinking in widgets and started thinking in pixels.

So I designed imp_trading_chart using a strict engine‑first architecture:

Candle Data (List<Candle>)
        ↓
ChartEngine (viewport, scaling, mapping)
        ↓
CustomPainter (draw only visible pixels)

Core principles

❌ No widget‑per‑candle
❌ No DateTime math in painters
❌ No unnecessary rebuilds
✅ Only visible data is processed
✅ Pan & zoom are O(1) operations
✅ Built for real‑time feeds

This design makes the chart fast, predictable, and scalable.

⚡ What `imp_trading_chart` Can Do

📈 Candlestick & line charts
🖐 Smooth pan & pinch‑to‑zoom
🎯 Crosshair with price & time tracking
🔄 Live tick updates
🎨 Fully customizable styles & layouts
🚀 Smooth with 10k+ candles

Under the hood:

CustomPainter‑based rendering
Viewport‑driven drawing
Cached price scaling
Immutable engine design

📊 Chart Variants Included

The package ships with multiple chart presets, all powered by the same engine:

Trading – full‑featured professional chart
Simple – clean chart with labels
Compact – dashboards & lists
Minimal – sparklines & previews

Different UI. Same core engine.

🚀 Quick Example

ImpChart.trading(
  candles: candles,
  currentPrice: candles.last.close,
  showCrosshair: true,
  defaultVisibleCount: 200,
);

No controllers required.
No heavy setup.

📦 Try It Yourself

🔗 pub.dev: https://pub.dev/packages/imp_trading_chart
🧪 A full interactive example app is included
📚 Deep internal documentation is provided

flutter pub add imp_trading_chart

🧩 Why Open Source?

Because chart engines are infrastructure, not just UI widgets.

I want this package to grow with the community — not behind closed doors.

If you:

Love performance work
Enjoy graphics, math, or engine design
Build trading, crypto, or fintech apps
Want to learn how chart engines really work

👉 You’re very welcome to contribute.

Even small contributions matter:

Documentation improvements
Refactors
Feature ideas
Bug reports

🛣 Roadmap

Planned next:

Public ChartController
Programmatic pan / zoom API
Indicator overlays (MA, EMA, VWAP)
More advanced examples

🙌 Final Thoughts

This is not just my first package.

It’s the result of two weeks of continuous brainstorming, learning, and curiosity — and I’m genuinely excited to see where the community takes it.

If this project sounds interesting:

⭐ Star the repo
🧪 Try the package
🧠 Open an issue
🔧 Send a PR

Let’s build something solid together 🚀

— Rahul Prajapati

DEV Community: Rahul Prajapati