Arbitrum Stylus - Solidity is Garbage for Math

I've been dealing with Solidity's garbage performance for years and this finally fixes it. Stylus dropped with ArbOS 32 in September 2024 - you can now deploy WASM contracts next to your Solidity contracts on Arbitrum.

Don't touch your existing Solidity. It keeps working exactly like before. But for the expensive computations that are bleeding your users dry? Write that shit in Rust. The VMs talk to each other so you're not throwing away months of contract development.

Here's what actually changes: crypto operations that cost $200 per call now cost $2. Complex math that hits gas limits? Runs fine. Ethereum's quadratic memory pricing has been cockblocking innovation for years - Stylus uses exponential pricing that starts way lower, so memory-heavy stuff actually works.

The MultiVM Architecture

Both EVM and WASM run on the same chain. Your old Solidity crap keeps working, but now you can write the performance-critical parts in Rust. Other chains force you to pick one VM or rebuild everything - Stylus lets them work together.

The setup:

• Solidity contracts - keep deploying like always, nothing changes
• Rust contracts - compile to WASM, deploy next to Solidity
• Cross-VM calls - your ERC20 can call a Rust pricing oracle in the same transaction
• Same infrastructure - still Arbitrum, same RPC endpoints

I deployed a Solidity contract that calls Rust math functions and it just works. The Rust SDK auto-generates the interfaces so calling between VMs feels natural. Uses standard Ethereum ABI so your existing tools understand it.

Why WebAssembly Doesn't Suck

WASM was built for browsers, which means it's already been battle-tested with millions of users trying to break it. If it can survive hostile web environments, it can handle blockchain.

What actually matters for contracts:

• Memory safety - no buffer overflows destroying your contract state like C++ would
• Deterministic execution - same inputs = same outputs, which consensus needs
• Compact size - smaller bytecode = lower deployment costs
• Real compilers - decades of LLVM optimization instead of Solidity's toy compiler

WASM runs at 2-3x native speed in benchmarks I've seen. Arbitrum's been using WASM for fraud proofs since the Nitro upgrade without issues, so the infrastructure already works at scale. Stylus just extends that to user contracts.

Language Support Reality Check

Technically any language that compiles to WASM works. In reality, most are a pain in the ass:

Actually Works:

• Rust - Official SDK, decent docs, reentrancy protection by default since it's finally affordable
• C/C++ - Compiles fine but you're handling all the Ethereum ABI shit manually

Good Luck:

• Go - Community efforts exist but expect to debug weird edge cases
• Sway - Fuel's pet language, minimal WASM support
• Cairo - Technically possible, practically you're on your own

Don't Even Try:

• Python/JavaScript - Need their own runtimes which makes WASM huge and gas metering a nightmare

Just use Rust. I spent weeks trying to get Go working and gave up. The Rust SDK handles reentrancy protection, ABI generation, and prevents the memory fuckups that destroy contracts. Learning Rust sucks but Solidity's limitations suck more.

The performance gains aren't marketing bullshit - they actually work. I've ported contracts and seen the difference firsthand. Here's what changes when you stop trying to do math in Solidity.

Where Gas Costs Actually Drop

Compute Gets Way Cheaper
Math operations that rape your gas budget in Solidity become affordable in Rust. That SHA256 hash costing 50k gas? Maybe 5k in Rust. Elliptic curve operations that hit gas limits? Run fine.

Real example from my own contracts: I had an AMM pricing curve that cost 80k gas per calculation in Solidity. Ported the exact same logic to Rust and it dropped to 8k gas. Users actually started using the sophisticated pricing instead of basic constant product because it wasn't bleeding them dry anymore.

Memory Actually Works Now

This is the big win. Stylus uses exponential pricing instead of EVM's quadratic pricing that fucks you over. Algorithms that would hit the gas limit with a few MB of data? Now they work with gigabytes.

I was building a sorting algorithm that hit Ethereum's memory wall at 6MB. Same algorithm in Stylus handled 100MB no problem. The cost grows exponentially but starts way lower - memory-heavy stuff that was impossible becomes doable.

Storage Doesn't Change Much
SLOAD and SSTORE cost the same as always, but the Rust SDK caches reads and batches writes better than my shitty Solidity code. Won't save you tons but helps if you're hitting the same storage slots repeatedly.

The Ink Pricing System

WASM operations are so fast they cost fractions of gas. Can't charge 0.1 gas for an operation since gas is whole numbers.

Stylus uses "ink" as fractional gas - 1 gas = 10,000 ink. You might see ink in debug tools but you still just pay gas. Conversion happens behind the scenes.

The result: operations that cost 1 gas minimum in EVM can now cost 0.1 or 0.01 gas in Stylus. That granular pricing is why compute gets so much cheaper.

What Actually Becomes Possible

Crypto Operations Stop Sucking
ZK proof verification that used to cost millions of gas? Now it's affordable. I tested elliptic curve operations that would hit the gas limit in Solidity - ran fine in Rust for under 100k gas. BLS signatures, Merkle tree stuff, all that crypto math that was impossible before actually works now.

Memory-Heavy Stuff Actually Works
Sorting large arrays? Works now. Complex data structures that would blow up in Solidity? Fine in Rust. I ran Monte Carlo simulations with 10k data points that would have been impossible before. Graph algorithms, dynamic programming, even basic ML inference - stuff that hit the memory wall now runs at scale.

Complex DeFi Math
AMM curves that cost too much gas per trade? Now they're viable. Derivatives pricing, yield calculations, all that financial math that was too expensive for on-chain. I built an options pricing model that would have cost $50 per calculation in Solidity - now it's under $1.

The Gotchas You Need to Know

Activation Costs Will Murder Your Wallet
First deployment costs 14 million gas. Yeah, that's $300-500 depending on gas prices. Nearly gave me a heart attack the first time. It's one-time per unique bytecode though - deploy the same code again and activation is free.

WASM Entry Overhead is Real
Every call into Stylus costs 128-2048 gas just to start WASM. Simple getters might actually cost more than Solidity. Stylus wins when you're doing real computation, not reading a single storage slot.

Size Optimization is a Pain
Some Rust crates are massive when compiled to WASM. I spent hours optimizing build flags and stripping debug symbols. The serde crate alone added 200KB to my contract. You'll be micro-managing dependencies to keep size down.

Debugging Sucks
Printf debugging is back. WASM tooling isn't close to Solidity's debugging experience. Rust prevents most bugs but when something breaks in production, figuring out what happened in the deployed WASM is a nightmare.