What Rollup SDKs Actually Abstract Away

SDKs abstract deployment, not operations. Tools like Arbitrum Orbit, OP Stack, and Polygon CDK generate a genesis block and smart contracts. They do not manage the sequencer, data availability layer, or bridge infrastructure required for a production network.

The hard part is stateful. The SDK handles stateless code compilation. You inherit the stateful burden of prover maintenance, multi-chain liquidity fragmentation, and cross-chain messaging via LayerZero or Axelar.

Abstraction creates vendor lock-in. Choosing an SDK like OP Stack commits you to its fault proof system and upgrade path. Migrating a live rollup to another stack is a hard fork, not a config change.

Evidence: The Celestia and EigenDA data availability wars prove the SDK's core value is outsourcing. The SDK itself is a wrapper for this critical, non-abstracted infrastructure choice.

Sequencer Operations are the first abstraction. SDKs like OP Stack and Arbitrum Orbit provide a default centralized sequencer, but the protocol inherits the operational risk and cost of running a high-availability node. The debt is migrating to a decentralized sequencer network like Espresso or Astria.

Data Availability (DA) is the most significant abstraction. Using a shared DA layer like Celestia or EigenDA reduces initial costs but creates vendor lock-in and cost volatility. The debt is the engineering effort to switch providers if pricing or security changes.

Proving Systems are abstracted through integration. A ZK-Rollup SDK like Polygon CDK bundles a proving backend, but the protocol is locked into its performance and cost curve. The debt is upgrading the proof system as new cryptography (e.g., Boojum, Plonky3) emerges.

Bridge and Messaging is abstracted via pre-built connectors. An SDK provides a native bridge to Ethereum, but the protocol must later integrate with cross-chain liquidity networks like LayerZero or Axelar for composability. This is deferred interoperability work.

Node Infrastructure is the final abstraction. SDKs assume the use of their node client, but the protocol must later incentivize a decentralized node operator set to run it, a non-trivial coordination problem that AltLayer and Conduit are solving for others.

SDKs abstract away data availability. You launch faster by using the SDK's default DA layer, but you inherit its cost structure and censorship risks. Migrating from a Celestia-based chain to an EigenDA-based chain later requires a hard fork.

SDKs abstract away sequencing. The SDK's default centralized sequencer provides low latency, but you cede control over MEV extraction and transaction ordering. This creates a vendor lock-in scenario similar to early AWS, where switching costs become prohibitive.

SDKs abstract away proof systems. You get a working ZK-rollup from Polygon CDK or zkSync's ZK Stack without writing a circuit, but you are bound to their proving infrastructure and cryptographic assumptions. Customizing for a new use case requires rebuilding the stack.

Evidence: The migration from Optimism Bedrock to the OP Stack required a complex, one-way upgrade for existing chains, demonstrating that early abstraction choices are not easily reversed.