Analyzes trade-offs of various consensus algorithms: finality time, throughput, decentralization. Configures and monitors validators in production networks. Understands slashing conditions and validator economics.
Roles · Blockchain Developer · Mid-level
What a Mid-level } should know
4 core skills, 79 in total. Expectations per skill, and what changes at the next level.
This page lists what a Mid-level } is expected to know and do, skill by skill. Core skills are the ones a manager and peers assess in a review cycle; the rest count only in self-assessment. Main areas: Blockchain & Web3.
4core skills
75additional skills
1skill areas
0%at Advanced or Expert
Core skills for a Mid-level
Grouped by area. The label on the right is the expected depth: Awareness, Working, Advanced or Expert.
Blockchain & Web3 · 4
Integrates DeFi protocols into blockchain infrastructure: event indexing, price feed aggregation, liquidity monitoring. Implements backend for DeFi position monitoring and health factors.
Configures and operates L2 nodes in production. Implements cross-layer messaging infrastructure (L1<->L2). Understands fraud proofs, validity proofs, and sequencer architecture.
Writes integration and fork tests for contract interaction with DeFi protocols. Uses Foundry fuzz testing to find edge cases. Tests upgrade paths and cross-contract calls.
Additional skills
Not assessed by the team, but part of the self-assessment and the development plan.
Algorithms & ComplexityAPI DocumentationAPI Documentation WritingApplied CryptographyApplied CryptographyAsync ProgrammingAWSBlockchain FundamentalsBlockchain Indexing: The Graph, SubgraphChatGPT / ClaudeClean CodeCode Quality & RefactoringCode ReviewCross-Chain BridgesCross-Chain BridgesCrypto EconomicsCursor IDEDAO GovernanceDApp DevelopmentData StructuresDatabase IndexingDesign PatternsDistributed SystemsDockerE2E TestingEthereum EcosystemEvent SourcingGit AdvancedGitHub Actions / GitLab CIGitHub CopilotGraphQL DesignIntegration TestingIPFS & Decentralized StorageKubernetes CoreKubernetes OrchestrationMerkle TreesMultithreadingNetwork FundamentalsNFT DevelopmentNFT StandardsNode OperationNode.js FrameworksOOP & SOLID PrinciplesOpenTelemetryOWASP & Application SecurityPerformance TestingPostgreSQLPrometheus & GrafanaPrompt Engineering for CodeReact CoreRedisREST API DesignRust LanguageSecure Coding PracticesSmart Contract AuditSmart Contract PlatformsSmart Contract Security & AuditingSoliditySolidity DevelopmentStructured LoggingSystem Design FundamentalsTerraformThreat ModelingToken StandardsTokenomics DesignType Safety & Type SystemsUnit TestingUnit TestingVyper DevelopmentWallet Integration: MetaMask, WalletConnectWeb3 Frontend: ethers.js, wagmiWeb3 LibrariesWebSocket API DesignZero-Knowledge ProofsZK-Rollups
What changes at Senior
79 skills get a higher expectation or become core when moving from Mid-level to Senior. The biggest jumps first.
- Applied Cryptography: Working → Advanced · becomes core
- Async Programming: Working → Advanced · becomes core
- Blockchain Fundamentals: Working → Advanced · becomes core
- Blockchain Indexing: The Graph, Subgraph: Working → Advanced · becomes core
- Cross-Chain Bridges: Working → Advanced · becomes core
- E2E Testing: Working → Advanced · becomes core
- Ethereum Ecosystem: Working → Advanced · becomes core
- Event Sourcing: Working → Advanced · becomes core
- GraphQL Design: Working → Advanced · becomes core
- Integration Testing: Working → Advanced · becomes core
Run this with your whole team
Self-assessment plus manager and peer reviews against the same matrix, gap analysis and next-level readiness for every engineer. Team Pro is free for 14 days; individual tools stay free forever.
} in the open competency matrix: 79 skills across 5 levels. The matrix is free for individuals and stays free.