Can You Explain How Rollups or Sidechains Differ From Purpose-Built Real-Time Settlement Platforms in Terms of Throughput and Cost?

Summary: Decision-makers weighing Ethereum rollups or sidechains against high‑throughput L1s like Solana, NEAR, Sui, or Sei should map two things: the latency you must guarantee and your per‑million‑transaction unit costs. Rollups inherit Ethereum security and have become dramatically cheaper post‑EIP‑4844, but still pay data‑availability and (for ZK) proving costs; purpose‑built real‑time L1s deliver sub‑second finality at fractions of a cent, trading off Ethereum settlement and some composability.

Who this is for

Startup and enterprise leaders designing trading, payments, gaming, or consumer apps that need a crisp answer to “How fast and how cheap, in production, not in theory?”
CTOs comparing OP Stack/Arbitrum/Base, Polygon PoS or appchains, and real‑time settlement L1s such as Solana, NEAR, Sui, and Sei.

TL;DR: Latency and cost profiles at a glance

Ethereum rollups (Optimistic and ZK): After EIP‑4844 (blobs), many L2 fees dropped 90–98%, but economics are dominated by blob DA costs and, for ZK, proving costs. Optimistic L2s still have 7‑day native withdrawal windows; fault‑proof systems are now live on OP Mainnet, improving trust assumptions. (blog.ethereum.org)
Sidechains (e.g., Polygon PoS, Gnosis Chain): Lowest fees because they don’t pay Ethereum DA each batch, but they don’t inherit L1 security the way rollups do; bridges are validator/governance‑secured. (l2beat.com)
Real‑time settlement L1s (Solana, NEAR, Sui, Sei): Sub‑second finality and sub‑cent fees purpose‑built for interactive apps and market microstructure. Example numbers: Solana base fee 0.000005 SOL (~$0.0005 if SOL=$100) with priority fees typically under $0.01; NEAR mainnet finality ~1.2s; Sui ~480 ms; Sei v2 ~390 ms with parallel EVM. (solana.com)

First principles: What you’re buying with each approach

Rollups: You buy Ethereum settlement security and broad EVM composability. Your unit cost is dominated by (a) L1 data availability (blobs) and (b) prover costs for ZK. Your latency is “L2 soft confirmation” fast, but your “L2→L1 native withdrawal” is slow on Optimistic unless you use a third‑party bridge. (blog.ethereum.org)
Sidechains: You buy sovereignty and ultra‑low fees with independent validators and bridges. Throughput and fee levels are under your own tokenomics and gas markets, not Ethereum’s. Security is only as strong as your validator set and bridge design. (l2beat.com)
Real‑time settlement L1s: You buy latency and throughput at the base layer with fees that are stable and tiny, sometimes at the cost of Ethereum‑native settlement and different MEV/fee‑market dynamics. These chains are engineered for parallel execution and fast finality. (blog.sei.io)

Throughput and latency: Production numbers you can plan around

Ethereum rollups after EIP‑4844
- Blobs give rollups a dedicated DA lane: up to 6 blobs/block, each 128 KB, pruned (~18 days) and much cheaper than calldata. Result: material fee collapse on Base, OP Mainnet, Starknet, etc. (blocknative.com)
- 150 days post‑Dencun (Mar 13–Aug 10, 2024): 2.23M blobs sold at ~$1.59/blob on average; rollups bought ~285 GB of blob data. (galaxy.com)
- Fees observed: reductions of 96–98% on Base/OP/Starknet. Current retail fees for top L2s often $0.01–$0.05. (thedefiant.io)
Sidechains
- Polygon PoS and Gnosis Chain are classified by L2BEAT as “Other/Sidechain” (not full rollups). They typically offer low fees and high daily txn capacity but rely on their own validator and bridge security. (l2beat.com)
Purpose‑built real‑time L1s
- Solana: 400 ms target slot times; base fee 5,000 lamports (=0.000005 SOL). Priority fees exist; Jito MEV auctions influence inclusion. Firedancer multi‑client rollout has begun, improving resiliency; lab tests hit 1M TPS, and as of 2025 a minority of stake ran Firedancer‑based clients. (solana.com)
- NEAR: 600 ms blocks and ~1.2 s finality on mainnet with Nightshade 2.0 “optimistic blocks.” Recent resharding expanded capacity. (pages.near.org)
- Sui: ~480 ms time to finality in globally distributed validator tests; high peak TPS in owned‑object workloads. (blog.sui.io)
- Sei v2: Parallelized EVM claiming ~390 ms block/settlement and up to 100 megagas/s throughput; v2 live since July 2024. Roadmap (“Giga”) targets 5 gigagas/s with sub‑400 ms finality. (blog.sei.io)

What this means: if your product’s SLA demands sub‑second finality visible to end users or market‑microstructure strategies that depend on deterministic speed, real‑time L1s will feel “snappier” than any L2 plus bridge model. If you need Ethereum settlement guarantees, L2s provide them, and now at far lower costs.

Cost mechanics: Where each dollar of fees actually goes

Rollups (Optimistic and ZK) after EIP‑4844
- DA cost (Ethereum blobs): A recent dataset pegs average blob cost per MB at ~$20.56 across rollups (varies by chain/time). Your per‑tx DA share is simply bytes_per_tx / 1,000,000 × $/MB. Example: if your batch compresses to 300 bytes/tx, DA ≈ 300/1e6×$20.56 ≈ $0.0062/tx. (conduit.xyz)
- ZK proving cost: Independent analyses estimate zkSync‑class proving at ~$0.0045/tx in 2024–2025, trending down with hardware and proof‑system optimizations. Some reports show proof cost drops from ~$80/proof (2023) to ~$1‑2/proof (2025), but your effective per‑tx depends on batch size and circuits. (chorus.one)
- Net effect: For a ZK rollup on Ethereum DA, all‑in marginal cost can sit in the low single‑digit cents, with DA and proving as the big drivers; for Optimistic rollups, DA dominates. Post‑4844, retail fees on major L2s commonly print 1–5 cents for simple actions. (thedefiant.io)
Sidechains
- Because they don’t post all data to Ethereum, unit costs are mostly local gas and validator economics. Fees are typically fractions of a cent to a few cents, but they can spike during mania events (e.g., Polygon PoS “inscription” spikes in late 2023). Security depends on the validator/bridge model rather than Ethereum’s fault/validity proofs. (support.polygon.technology)
Real‑time settlement L1s
- Solana’s base fee is fixed (5,000 lamports per signature); most transactions add tiny priority fees. At SOL=$100, base ≈ $0.0005; even under load, fees often stay sub‑cent to low cents per interaction. Fee‑market nuances (local fee markets, Jito auctions) matter for HFT‑like workloads. (solana.com)
- NEAR, Sui, Sei keep fees low via high throughput and parallel execution. Sei reports ~100 Mgas/s with ~390 ms finality; users observe low‑cent or sub‑cent fees in practice (final fee depends on chain token price). (blog.sei.io)

Data availability choices now move the fee needle—by orders of magnitude

Ethereum blobs (EIP‑4844): Dedicated, ephemeral DA lane; costs are way down versus calldata and have their own 1559‑style fee market. (blog.ethereum.org)
Celestia DA: DA‑only L1 with predictable pricing. Public estimates range from ~$0.10/MB during quiet periods to a single‑digit dollars/MB average depending on demand. Using the same 300‑bytes/tx example, DA ≈ 300/1e6×$0.10 ≈ $0.00003/tx—orders of magnitude cheaper than Ethereum DA, at the cost of additional trust assumptions. (celestiaorg.github.io)
EigenDA: Restaking‑secured DA boasting reported mainnet throughput up to 100 MB/s (vendor numbers) and a 2024–2025 “free tier” rollout; several rollups already integrate. Pricing is evolving, but headline bandwidth suggests room for low per‑tx DA costs. (linkedin.com)
Avail: DA mainnet live with 100+ active validators; projects are integrating for lower DA spend and modular architectures. (forum.availproject.org)

Practical takeaway: DA is no longer one size fits all. You can materially lower L2 unit costs by moving from Ethereum blobs to Celestia/EigenDA/Avail, but you must account for the extra trust assumptions (and regulator comfort) that come with non‑Ethereum DA. (l2beat.com)

What “finality” actually means in your app’s UX

Optimistic L2s: The “7‑day delay” is about L2→L1 bridge finality, not your app’s internal confirmations. Onchain, users see quick L2 inclusion; funds can be bridged out instantly via liquidity providers (for a fee). Permissionless fault proofs are now live on OP Mainnet, tightening the trust model for withdrawals. (ethereum.org)
ZK L2s: Validity proofs enable faster native withdrawals once a proof verifies on L1; user‑perceived finality is often a few minutes. (l2beat.com)
Real‑time L1s: Settlement is native and fast on the base chain—no L2→L1 bridge semantics—so what users feel is what settles. NEAR ~1.2 s finality; Sui ~480 ms; Sei ~390 ms; Solana targets sub‑second blocks and sub‑cent fees. (pages.near.org)

Practical scenarios with concrete, recent data

Real‑time payments rails and B2B settlements

Example: Visa expanded USDC settlements for U.S. issuers/acquirers on Solana in December 2025, citing 24/7 availability and faster treasury movement. If your SLA is “card‑network‑grade operations on weekends/holidays,” a high‑throughput L1 with sub‑cent fees is now proven in production. (usa.visa.com)

Market‑making or latency‑sensitive trading

Tight loops (cancel/replace, multi‑leg routing) benefit from deterministic sub‑second settlement. Solana’s low fees plus priority mechanics, Sui’s ~480 ms finality, or Sei’s parallel EVM with ~390 ms block times are a fit. Rollups can work for non‑latency‑critical DeFi, especially post‑4844 cost reductions. (blog.sui.io)

Consumer apps at web‑scale

If you need “free‑ish” UX at hundreds of millions of tx/day, either:
- Choose a real‑time L1 with very low fees; or
- Use a rollup with cheap DA (Celestia/EigenDA) and aggressive compression. With Celestia at ~$0.10/MB, your DA cost at 200 bytes/tx is ~0.002 cents; ZK proving then dominates the budget. (celestiaorg.github.io)

Regulated, asset‑heavy businesses that must anchor to Ethereum

Prefer an OP Stack or Arbitrum rollup that posts data to Ethereum blobs and has live fault or fraud proofs. Model fees with: DA $/MB × bytes/tx + sequencer margin + (for ZK) amortized proving; expect single‑digit cents for typical interactions post‑4844. (blog.oplabs.co)

Emerging best practices we’re advising in 2026

Be explicit about DA economics in your P&L. Track bytes/tx with real traces, not whiteboard estimates. Compare Ethereum blob averages (~$20.56/MB over a recent rollup set) to Celestia/EigenDA options and compute your $/million‑tx sensitivity. (conduit.xyz)
Treat ZK proving as an infrastructure line item. Benchmarks place proving near ~0.3–1.0¢/tx today (batch‑dependent), trending down with new provers (e.g., StarkWare’s open‑sourced Stone/Stwo) and specialized hardware. Don’t ignore vendor lock‑in or centralized prover risk. (chorus.one)
Demand sequencing guarantees. Shared/decentralized sequencers matured unevenly—some networks (e.g., Astria) wound down in late 2025. For OP Stack/Arbitrum, follow decentralization roadmaps and ensure forced‑inclusion, permissionless proving, and credible liveness. (unchainedcrypto.com)
Understand fee markets on real‑time L1s. On Solana, base fees are tiny but inclusion priority can involve priority fees and off‑protocol auctions (Jito). Engineer for burst loads, not averages, and monitor local hotspots. (solana.com)
If you must bridge to/from Ethereum frequently, prefer ZK rollups (faster native exits) or budget for instant‑bridge liquidity spreads on Optimistic rollups. Revisit this as OP Stack fault proofs propagate across Superchain L2s. (blog.oplabs.co)
Follow multi‑client resiliency. Solana’s Firedancer rollout increases client diversity, reducing single‑implementation risk that has caused past outages; this matters for enterprise uptime SLAs. (solana.com)

Decision framework you can apply this week

If your app needs sub‑second, on‑chain finality (market microstructure, in‑game actions, streaming payments): start on a real‑time L1 (Solana/NEAR/Sui/Sei) and design fee‑aware orderflow with priority fees where relevant. Validate your latency budget with live network traces. (pages.near.org)
If your primary risk constraint is “settle to Ethereum” with mainstream EVM tooling: build on an OP Stack/Arbitrum/Base rollup. After 4844, retail fees are cents; your DA/prover choices control the long tail of unit economics. For aggressive cost targets, consider alt‑DA (Celestia/EigenDA) with clear disclosures of additional trust assumptions. (blog.ethereum.org)
If you want ultra‑low fees and sovereign control and can accept non‑Ethereum security: a sidechain or app‑chain is viable. Budget dedicated work on bridge risk, validator ops, and upgrade governance. (l2beat.com)

Brief, concrete examples (2026‑ready)

Invoice micropayments at scale (10M tx/day):
- Rollup on Celestia DA: assume 200 bytes/tx, DA ≈ $0.00002/tx; add 0.3–1.0¢ proving (ZK) → total ≈ 0.3–1.0¢/tx plus sequencer margin. (celestiaorg.github.io)
- Solana: base ~$0.0005 + small priority fees, typically <1¢. End‑to‑end UX feels instant. (solana.com)
Corporate treasury settlement:
- Visa’s USDC settlement for U.S. banks on Solana shows weekend‑safe, 24/7 flows; model operational gains against internal ledgering. (usa.visa.com)
High‑frequency swap router:
- Latency budget <500 ms? Sei/Sui/Solana provide settlement speed; if you need Ethereum composability, consider a ZK L2 plus fast bridges for multi‑domain routing. (blog.sei.io)

What’s new since 2024 that should change your plan

EIP‑4844 is live and working: blob‑based DA slashed L2 fees, with Base/OP/Starknet seeing 96–98% reductions; your 2022 L2 cost assumptions are obsolete. (blog.ethereum.org)
OP Stack fault proofs are live on OP Mainnet, improving withdrawal trust without a privileged proposer. Expect propagation to Superchain L2s. (blog.oplabs.co)
Multi‑client Solana is real: Firedancer deployment across a subset of validators began, materially improving resiliency and future throughput headroom. (solana.com)
DA market expanded: EigenDA V2 (reported up to 100 MB/s) and Celestia pricing transparency give rollups new levers to tune cost vs trust assumptions. (linkedin.com)

How 7Block Labs helps

Architecture sprints that map your SLA (latency/finality) to concrete chain choices and unit‑economics targets, with byte‑level DA and proof cost modeling.
Rollup builds (OP Stack/Arbitrum/Polygon CDK), DA integrations (Ethereum blobs, Celestia, EigenDA), and production observability for fee and latency regressions.
Real‑time L1 builds (Solana/Sei/Sui/NEAR), including fee‑market tuning (priority fees, auctions) and client diversity strategy for resiliency.

If you share your target TPS, desired finality, and per‑million‑tx budget, we’ll return a build plan and cost curve within a week.

References and data sources:

Dencun/EIP‑4844 mainnet activation and blob mechanics; observed fee drops on L2s. (blog.ethereum.org)
Post‑Dencun blob usage and costs (Galaxy Research). (galaxy.com)
Ethereum blob transaction limits and details (Blocknative). (blocknative.com)
L2 retail fee snapshots (L2Fees.info). (l2fees.info)
OP Stack fault proofs live on OP Mainnet. (blog.oplabs.co)
Arbitrum fraud‑proof docs (BoLD, multi‑round). (docs.arbitrum.io)
Polygon PoS classified as sidechain and its migration intentions. (l2beat.com)
Solana fee schedule and fee‑market mechanics; Firedancer status and network reports. (solana.com)
NEAR 600 ms blocks and ~1.2 s finality; resharding upgrades. (pages.near.org)
Sui performance update (~480 ms finality). (blog.sui.io)
Sei v2 parallelized EVM performance and Giga roadmap. (blog.sei.io)
DA alternatives: Celestia docs/pricing context; EigenDA throughput/pricing updates; Avail mainnet validator set. (celestiaorg.github.io)
Visa USDC settlement on Solana for U.S. institutions (Dec 16, 2025). (usa.visa.com)

Need a numbers‑first plan for your product? 7Block Labs can run a quick discovery to benchmark your options and model exact per‑tx costs under real workloads.