Multi-Chain Wallet Backend Rebuild for a Token Ecosystem

A token ecosystem operating a consumer-facing wallet across six cryptocurrency chains. The wallet had launched on a client-side architecture where each supported chain shipped as a library bundled into the wallet binary, talking to public RPCs directly.

The wallet worked acceptably for the chain the team had built first and degraded predictably for the rest. Public RPCs throttled requests at exactly the wrong moments. Fee estimation logic that had been correct at launch had aged badly as fee market dynamics evolved. Confirmation lifecycle behavior was inconsistent across chains because each chain's library handled it slightly differently. Adding a seventh chain was on the roadmap and the team had concluded — correctly — that the existing architecture would not survive the addition.

A backend orchestration layer that took ownership of the chain-specific knowledge.

The wallet client was rewritten to talk to a single well-defined orchestration API rather than to chain libraries directly. The backend coordinator held one chain handler per supported chain — Bitcoin's UTXO model, Ethereum's account model, BSC's EVM compatibility, Polygon's bridging behavior, USDT's multi-chain handling, native LTC. Each handler owned its chain's RPC failover, its fee estimation against current market conditions, and its confirmation lifecycle semantics.

RPC infrastructure moved from public endpoints to a managed pool with per-chain failover, rate limiting, and the kind of observability that surfaces RPC health before it surfaces as a user-facing failure. Fee estimation logic became operationally updatable — when a chain's fee market behavior shifted, the change was deployed at the orchestration layer rather than requiring a wallet binary release.

The client-side wallet was simplified accordingly. The chain abstraction collapsed into a single API surface; chain selection became a parameter rather than a code path. The seventh chain that had been on the roadmap was added at the orchestration layer in days rather than the multi-week effort the previous architecture would have required.

The wallet's reliability across all six chains converged on the level the team had previously achieved only on the chain they had built first. RPC-related incidents stopped surfacing as user-visible failures. The team gained operational control over chain-specific behavior without shipping new wallet builds. The seventh chain was added without disruption. The eighth and ninth, when the team chose to add them later, took less engineering effort each than the previous architecture had required for any single one.