Substrate & ink!

Build blockchains with Substrate FRAME pallets and smart contracts with ink! - Rust-native Web3 infrastructure.

Recipe

Minimal ink! contract skeleton:

#[ink::contract]
mod flipper {
    #[ink(storage)]
    pub struct Flipper {
        value: bool,
    }
 
    impl Flipper {
        #[ink(constructor)]
        pub fn new(init: bool) -> Self {
            Self { value: init }
        }
 
        #[ink(message)]
        pub fn flip(&mut self) {
            self.value = !self.value;
        }
 
        #[ink(message)]
        pub fn get(&self) -> bool {
            self.value
        }
    }
}

When to reach for this:

• Launching a custom L1/L2 with tailored consensus and fees
• Polkadot/Kusama parachains or solochains
• Wasm contracts when EVM is not required

Working Example

Pallet storage and dispatch pattern (conceptual FRAME snippet):

#[frame_support::pallet]
pub mod pallet {
    use frame_support::pallet_prelude::*;
    use frame_system::pallet_prelude::*;
 
    #[pallet::pallet]
    pub struct Pallet<T>(_);
 
    #[pallet::config]
    pub trait Config: frame_system::Config {}
 
    #[pallet::storage]
    pub type Value<T> = StorageValue<_, u32, ValueQuery>;
 
    #[pallet::call]
    impl<T: Config> Pallet<T> {
        #[pallet::call_index(0)]
        #[pallet::weight(10_000)]
        pub fn set(origin: OriginFor<T>, v: u32) -> DispatchResult {
            ensure_signed(origin)?;
            <Value<T>>::put(v);
            Ok(())
        }
    }
}

What this demonstrates:

• Storage items typed and namespaced per pallet
• ensure_signed authorization guard
• Weight annotation for block limits

Deep Dive

How It Works

• Substrate node runs networking, consensus, and Wasm runtime executor.
• Runtime is compiled Wasm blob upgraded via set_code governance.
• ink! contracts deploy to pallet-contracts with rent and storage trie.
• Extrinsics are transactions; storage uses efficient key-value maps.

Substrate vs ink!

Gotchas

• Runtime bloating - too many pallets increases Wasm size and compile time. Fix: feature-gate experimental pallets.
• Storage unbounded growth - maps without deposit fees spam chain. Fix: charge rent or require bonds per entry.
• ink! panic becomes revert - no Rust panic recovery on-chain. Fix: return Result from messages, avoid unwrap.
• Weight underestimation - blocks full, chain stalls. Fix: benchmark with frame_benchmarking.
• Off-chain worker trust - unsigned submissions need validation. Fix: verify signatures and staleness on-chain.

Alternatives

FAQs

Related

• Blockchain Basics in Rust - hashing and keys
• Consensus & P2P - networking layer
• Applied Cryptography - crypto primitives
• Solana Programs - alternative on-chain model

Stack versions: This page was written for Rust 1.97.0 (edition 2024), Tokio 1.x, Axum 0.8, serde 1.0, sqlx 0.8, clap 4, and Polars 0.46+.