https://nikolaishelekhov.com Nikolai is a Rust software engineer building high-performance systems, backend and blockchain infrastructure. Zola en Sun, 09 Nov 2025 00:00:00 +0000 Sun, 09 Nov 2025 00:00:00 +0000 Nikolai Shelekhov https://nikolaishelekhov.com/blog/substrate-price-oracle/ https://nikolaishelekhov.com/blog/substrate-price-oracle/ <p>Accurate price data is foundational to any DeFi system.</p> <p>DEXs, lending protocols, liquidations, MEV strategies —<br /> all depend on reliable and timely asset pricing.</p> <p>Instead of relying purely on external infrastructure, I wanted to explore a runtime-native approach using Substrate.</p> <h2 id="the-goal">The Goal</h2> <p>Design a modular price oracle pallet that:</p> <ul> <li>Fetches asset prices from external sources</li> <li>Aggregates them deterministically</li> <li>Stores them on-chain</li> <li>Exposes them to other runtime modules</li> </ul> <p>The constraint: maintain composability and determinism at the runtime level.</p> <h2 id="architecture-overview">Architecture Overview</h2> <p>The design uses Substrate’s off-chain workers:</p> <ol> <li>Off-chain worker fetches external price data</li> <li>Data is validated and formatted</li> <li>An unsigned transaction submits updated price information</li> <li>Runtime storage is updated</li> </ol> <p>This keeps:</p> <ul> <li>Network requests off the runtime path</li> <li>Deterministic execution within the state machine</li> <li>Minimal trust assumptions beyond data sources</li> </ul> <h2 id="key-design-decisions">Key Design Decisions</h2> <h3 id="1-off-chain-workers">1. Off-Chain Workers</h3> <p>External HTTP requests cannot block runtime execution.</p> <p>Off-chain workers allow background fetching without compromising block production.</p> <h3 id="2-fixed-point-arithmetic">2. Fixed-Point Arithmetic</h3> <p>Floating-point operations are not deterministic across architectures.</p> <p>All price calculations use fixed-point arithmetic to ensure:</p> <ul> <li>Deterministic execution</li> <li>Predictable rounding</li> <li>Cross-node consistency</li> </ul> <h3 id="3-storage-layout">3. Storage Layout</h3> <p>Prices are stored in optimized maps keyed by asset identifiers.</p> <p>Design priorities:</p> <ul> <li>Fast reads (price access is frequent)</li> <li>Minimal storage overhead</li> <li>Clear upgrade path</li> </ul> <h2 id="why-not-just-use-an-external-oracle">Why Not Just Use an External Oracle?</h2> <p>External oracle networks are powerful — but they introduce:</p> <ul> <li>Latency</li> <li>Trust layers</li> <li>Dependency on third-party infrastructure</li> </ul> <p>Embedding oracle logic inside the runtime:</p> <ul> <li>Improves composability</li> <li>Reduces architectural complexity</li> <li>Enables tighter integration with DeFi pallets</li> </ul> <p>For experimentation and MEV research, this approach gives full control over the data lifecycle.</p> <h2 id="what-i-learned">What I Learned</h2> <p>Building runtime logic reinforces an important principle:</p> <p>Blockchain development is systems programming.</p> <p>You’re writing deterministic state machines, with strict performance constraints, and zero room for undefined behavior.</p> <p>Rust and Substrate make that not only possible — but enjoyable.</p> Sun, 12 Oct 2025 00:00:00 +0000 Nikolai Shelekhov https://nikolaishelekhov.com/blog/blockchain-or-rust/ https://nikolaishelekhov.com/blog/blockchain-or-rust/ <p>A few months ago, I was asked in an interview:</p> <p>“What do you love more — Rust or blockchain?”</p> <p>My answer was immediate.</p> <p>Rust comes first.</p> <p>But not just any Rust work — deep, idiomatic, systems-level Rust programming.</p> <h2 id="rust-first">Rust First</h2> <p>What draws me to Rust is not hype.</p> <p>It’s:</p> <ul> <li>Memory safety without garbage collection</li> <li>Zero-cost abstractions</li> <li>Explicit control over performance</li> <li>Deterministic behavior</li> <li>Strong type-driven design</li> </ul> <p>Rust feels like systems programming done correctly.</p> <p>That foundation matters more to me than the domain.</p> <h2 id="blockchain-but-only-at-the-right-layer">Blockchain — But Only at the Right Layer</h2> <p>If I work in blockchain, it has to be infrastructure.</p> <p>Not smart contracts. Not application-layer glue code. Not framework-heavy abstraction stacks.</p> <p>There is a fundamental difference between:</p> <ul> <li>Building on top of someone else’s platform</li> <li>Building the platform itself</li> </ul> <p>I’m interested in the second.</p> <h2 id="why-polkadot">Why Polkadot</h2> <p>Polkadot stands out for one specific reason:</p> <p>It is pure Rust.</p> <p>Substrate is not a thin wrapper around another runtime. It is not macro-driven sugar hiding complexity. It exposes the machinery.</p> <p>You write runtime logic. You design state transitions. You control storage. You reason about determinism.</p> <p>It feels like systems engineering — not scripting on-chain.</p> <p>That alignment matters.</p> <h2 id="infrastructure-over-applications">Infrastructure Over Applications</h2> <p>I am drawn to:</p> <ul> <li>Runtime design</li> <li>Consensus-adjacent components</li> <li>Performance-critical infrastructure</li> <li>Cross-chain execution logic</li> <li>State machine design</li> </ul> <p>Not UI. Not token launches. Not yield optimizers.</p> <p>I want to work on the systems that make everything else possible.</p> <h2 id="the-boundary-i-ve-drawn">The Boundary I’ve Drawn</h2> <p>My focus is clear:</p> <ul> <li>Deep systems programming in Rust</li> <li>Blockchain infrastructure (not application layer)</li> <li>Preferably within the Polkadot ecosystem</li> </ul> <p>That doesn’t invalidate other paths.</p> <p>It just reflects what I value.</p> <h2 id="why-this-matters">Why This Matters</h2> <p>Careers compound.</p> <p>If you spend years writing surface-level abstractions, you become good at surface-level abstractions.</p> <p>If you spend years designing deterministic state machines, optimizing performance, and reasoning about low-level invariants,</p> <p>you become something else entirely.</p> <p>I choose the latter.</p> <p>Rust is the constant. Blockchain is optional — but only when it allows Rust to be used at its full depth.</p> <p>That’s the line I’ve drawn.</p>