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Feels Protocol

Solana DEX Trading Platform

Overview

Role: Main developer — owned the platform end-to-end: the Next.js trading UI, the Rust indexer/backend, the on-chain integration, and CI/CD.

End-to-end ownership of a Solana DEX: Next.js 16 trading frontend and a Rust real-time indexer. Two streaming modes (mock Geyser for localnet/CI, Yellowstone gRPC for devnet/mainnet) switch via a Cargo feature flag, and a two-lane Playwright harness validates deployment coherence across frontend env, RPC, indexer, program ID, and token mints before any product assertion runs.

Key Features

  • End-to-end ownership of Next.js trading frontend + Rust real-time indexer
  • Two-lane Playwright E2E: deterministic test wallet + LiteSVM in-memory RPC
  • Deployment-coherence pre-check across frontend env, RPC, indexer, program ID, and token mints
  • dev:mock / dev:live split eliminating silent mock-fallback bugs
  • Single API proxy ingress with ESLint-enforced boundary
  • Streaming-mode switch (mock Geyser ↔ Yellowstone gRPC) via Cargo feature flag

Tech Stack

Frontend

Next.js 16React 19TypeScriptTailwind CSSBun

Indexer

RustTokioAxumBorshsqlx

Storage & Search

PostgreSQLRocksDBRedisTantivy

Solana & Web3

Solana wallet adaptersYellowstone gRPCMetaplexWASM

Testing & Observability

PlaywrightLiteSVMScalar OpenAPIPrometheus

Challenges & Solutions

Untrusted Browser-to-Indexer Access

Problem

A trading SPA talking directly to the indexer from the browser opens cross-origin fetch and token-leak risks, and the boundary erodes the moment any component reaches for a raw fetch.

Solution

Routed all browser-to-indexer traffic through a single API proxy as the only ingress, and enforced it with a custom ESLint rule that bans raw cross-origin fetch in the app, removing whole classes of CSRF and token-leak bugs.

Indexing High-Volume On-Chain State

Problem

Deserializing and serving 10+ Solana account types and on-chain events at trading-app latency needs more than a single database can offer.

Solution

Built a Rust indexer on Tokio over a four-backend storage layer — PostgreSQL for analytics, RocksDB for raw account state, Redis for hot cache, and Tantivy for token search — with discriminator-routed Borsh deserialization and a Cargo feature flag switching between mock Geyser and Yellowstone gRPC streaming.

Slow, Flaky Full-Stack Tests

Problem

On-chain integration tests against a live validator were slow and non-deterministic, and env drift between frontend, RPC, indexer, and on-chain program made failures hard to trust.

Solution

Built a two-lane Playwright setup — a deterministic test-wallet lane and a LiteSVM in-memory RPC lane — and added a deployment-coherence pre-check asserting frontend env, RPC, indexer URL, program ID, and token mints all match before any product assertion runs.

Key Achievements

End-to-End
Next.js frontend + Rust indexer owned solo
2-Lane E2E
Deterministic Playwright on LiteSVM in-memory RPC
4 Backends
Multi-tier storage behind ~40 REST endpoints
30+ Components
Full trading UX across the SPA