BAC-L1-FOUND-118
APIs, JSON-RPC and node integration
Talking to a chain from code: calls, subscriptions, errors, rate limits, and the discipline of never trusting a single source.
- Level
- L1 — Blockchain developer
- Duration
- 4 h
- Track
- Foundation
- Maintainer
- Developer Curriculum Architect
Learning objectives
- 01Query a node over JSON-RPC and handle its error codes
- 02Subscribe to events over WebSocket
- 03Design a fallback strategy for a failing endpoint
Guided lab
Write a client that follows new blocks and survives its endpoint going away.
Independent lab
Extend the client to compare two RPC providers and alert on divergence.
Security angle
An RPC provider sees everything the user looks up: privacy consequences and mitigations.
Assessment
Resilient client, tested by deliberately killing the endpoint.