did:polygon vs did:hedera: EVM L2 vs DAG L1 for DIDs

Seamless composability with Ethereum tooling like MetaMask, Hardhat, and OpenZeppelin. This matters for teams building cross-chain dApps that require familiar wallets and smart contract standards (ERC-725, ERC-1056).

High-speed, low-variance finality via Hashgraph consensus (<3 sec). This matters for high-frequency credential issuance/verification (e.g., supply chain tracking, KYC flows) where predictable performance is critical.

Stable, ultra-low fees insulated from Ethereum mainnet congestion. This matters for mass-scale DID deployments (e.g., for gaming or social platforms) where per-user cost must remain negligible and predictable.

Built-in identity layer with Hedera Consensus Service (HCS) and approved node governance (Google, IBM, Deutsche Telekom). This matters for enterprises in regulated sectors (finance, healthcare) that require auditable, permissioned consensus.

EVM Compatibility: Seamless integration with the vast Ethereum tooling ecosystem, including wallets like MetaMask, frameworks like Hardhat, and standards like ERC-725/ERC-735. This matters for teams already building on Ethereum who want to launch DIDs with minimal friction.

High Throughput & Low Cost: As a ZK-rollup, Polygon zkEVM offers ~100+ TPS and transaction fees under $0.01, making it cost-effective for high-volume DID operations like credential issuance and verification. This matters for applications scaling to millions of users.

Sequencer Centralization Risk: Relies on a single sequencer for transaction ordering, creating a potential liveness dependency. While decentralized sequencers are planned, this is a current architectural consideration for mission-critical, censorship-resistant identity systems.

Asynchronous Finality & Fair Ordering: Hedera's hashgraph consensus provides ~10k+ TPS with ~3-5 second finality and built-in fair transaction ordering (no MEV). This matters for DID systems requiring deterministic, tamper-proof audit trails and high fairness guarantees.

Predictable, Stable Fees: Transaction fees are fixed in USD (e.g., ~$0.0001) and governed by council, eliminating gas price volatility. This matters for enterprise applications that require precise, budgetable operational costs for credential lifecycle management.

Non-EVM Native Environment: While EVM compatibility exists via the Hedera Smart Contract Service, the core network uses a bespoke API and consensus model. This matters for teams deeply invested in Solidity/EVM toolchains, as it may require a learning curve and adapter development.

Gas fees are stable and extremely low: Transaction fees on Polygon PoS are typically <$0.01, with predictable gas pricing via the EVM model. This matters for high-volume DID operations like issuing thousands of verifiable credentials (VCs) where cost spikes are unacceptable.

Asynchronous Byzantine Fault Tolerance (aBFT) consensus: Provides ~3-second finality with mathematically proven security, unlike probabilistic finality in many blockchains. This matters for high-assurance identity events (e.g., credential revocation) where instant, irreversible confirmation is critical.

USD-denominated, council-governed fee schedule: A DID creation (HTS token association) costs ~$0.05, and a standard transaction is $0.0001. Fees are fixed in USD, not volatile crypto. This matters for enterprise budgeting and compliance where operational costs must be forecastable for years.

Relies on Ethereum for checkpointing: Security is ultimately derived from Ethereum's L1, which is robust but introduces a dependency. This matters if you require a fully independent, purpose-built ledger for identity with its own consensus, rather than a secured sidechain.

Unique Hashgraph architecture: Not an EVM chain, requiring use of the Hedera Token Service (HTS) for did:hedera and SDKs like hedera-sdk-js. This matters for teams deeply invested in EVM tooling who may face a learning curve, despite Hedera's growing Web3.js and Ethers.js compatibility.