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Build an Indexer for an On-Chain DeFi Analytics Product

FreeVerified credential3 weeksAdvanced

Overview

What this challenge is about.

Receive the 6 protocols' ABIs + the team's required event coverage spec (around 40 event types). Build a TypeScript indexer using viem + Postgres: subscribe to new blocks via WebSocket, decode events for the 6 protocols, write to Postgres in idempotent batches. Handle reorgs by tracking last-finalized block and rewriting affected ranges. Add an exponential-backoff retry layer for RPC failures. Stress-test: replay 30 days of mainnet history + simulate 10-block reorgs. Prove zero event loss and steady-state 'within 2 blocks of tip'. Deliver TypeScript code, the schema migrations, a benchmark report, and a 5-page operations runbook.

CredentialBlockchain-anchored
ShareableLinkedIn-ready
LanguageEnglish
PaceSelf-paced

The Brief

What you'll do, and what you'll demonstrate.

Build a reorg-safe DeFi indexer that stays within 2 blocks of tip across 6 protocols on Ethereum + Arbitrum with zero event loss across a 30-day replay.

Earning criteria — what you'll demonstrate

  • Build a reorg-safe blockchain indexer in TypeScript
  • Decode ABI events idempotently into a relational schema
  • Handle network + RPC failures with backoff + retry patterns
  • Document the indexer's failure modes for operations

Program Fit

Where this fits in your program.

Sharpens the same skills your degree expects you to demonstrate.

Skills

Skills you'll demonstrate.

Each one shows up on your verified credential.

Careers

Roles this prepares you for.

Real titles. Real skill bridges. Pick the one closest to your trajectory.

Career mappings coming soon.

One more thing

You can put a credential on your CV by Friday.