Can you explain how rollups or sidechains differ from purpose-built real-time settlement platforms in terms of throughput and cost?

Summary: This guide compares Ethereum rollups and sidechains to purpose-built real-time settlement L1s on two axes that decide user experience and unit economics—throughput and cost—using current post‑Dencun data, concrete configuration tips, and practical selection playbooks for startup and enterprise teams.

TL;DR for decision‑makers

If you need sub‑second user confirmations and near‑free micro‑payments at massive scale, a purpose‑built real‑time L1 (e.g., Solana, NEAR, Avalanche, XRPL, Hedera, Stellar) will usually deliver the best latency/price today. Expect finality within seconds and per‑tx costs measured in fractions of a cent. (solana.com)
If you need Ethereum security/composability and predictable onboarding to the EVM ecosystem, modern rollups are now extremely cheap post‑EIP‑4844 and scale horizontally, but their sustainable throughput is bounded by data‑availability (DA) limits and they inherit L1 settlement latency patterns. Sidechains are cheaper and faster than L1 Ethereum but add independent consensus/trust and operational risk. (eips.ethereum.org)

Below, we go deep on how those differences show up in your throughput headroom and cost per transaction, and what you can do (right now) to tune either stack.

What “throughput” and “cost” really mean in 2025

Throughput: the number of user operations you can push through per second without degrading UX. For rollups, this is primarily bounded by L1 DA capacity (blobs per block) and your batcher settings; for monolithic L1s, by validator bandwidth and block production. (eips.ethereum.org)
Cost: the marginal cost per transaction users pay (fees), plus your own infrastructure and DA charges. On rollups post‑4844, most marginal cost is “blob data per tx × blob gas price”; on real‑time L1s it’s base+priority fees denominated in the L1 token (or USD on Hedera). (eips.ethereum.org)

Rollups: how much throughput and how cheap, really?

The DA ceiling after EIP‑4844 (Dencun)

EIP‑4844 introduced “blob” transactions: each blob is ~128 KiB and Ethereum allows a target of 3 blobs per 12‑second slot (max 6), giving on the order of 32–64 KiB/s of affordable L2 data capacity per slot today. That’s the system‑wide budget rollups are competing for. (eips.ethereum.org)
In practice, the DA lane has run hot: L2BEAT has shown >80% blob capacity utilization over recent days and one L2 (Base) often being the largest poster. That means your L2’s sustainable TPS is ultimately a function of how efficiently you compress transactions into blob bytes. (l2beat.com)

What this implies:

Your batcher and compression strategy is your TPS lever. Systems like Arbitrum Nitro brotli‑compress batches and charge each tx its estimated L1 data share; the better you compress, the more TPS you squeeze from the same blob budget. (research.arbitrum.io)

What 4844 did to fees

By moving data from calldata to blobs, many rollups saw 50–98% fee cuts. Sub‑cent to low‑cent per tx is now normal for simple transfers; swaps are often measured in low cents depending on congestion. (thedefiant.io)

Practical rule of thumb (post‑Dencun):

For a simple ERC‑20 transfer on a major optimistic rollup, budget sub‑$0.01 in quiet hours and several cents during spikes; for swaps, a few cents. Monitor your chain’s blob price and batcher cadence to keep under targets. (thedefiant.io)

Latency: “soft confirmation” vs settlement finality

Users get sub‑second “sequencer confirmations,” but L1 anchoring happens on a cadence you control. On Nitro‑based stacks, the default max delay to post a batch is 1 hour; most production teams set 5–15 minutes to balance cost and UX. Remember there’s also an assertion cadence and a fraud‑proof window (~7 days) for optimistic rollups. (docs.arbitrum.io)

Tuning tips you can apply this week:

Set batcher max‑delay to 5–15 minutes. This keeps perceived UX tight while preserving compression.
Increase batch size thresholds during peaks to maintain high blob utilization.
Instrument “bytes per L2 tx” and correlate with blob gas to predict fee bands hour‑ahead.

How to break past 4844 ceilings

Alt‑DA: Posting to Celestia or EigenDA decouples your throughput from Ethereum’s blob lane. Celestia mainnet currently supports large data squares (e.g., 8 MiB max square) and scales with DAS; EigenDA has publicly reported high MB/s targets on mainnet. Validate SLAs, cost, and security assumptions before switching. (docs.celestia.org)
Shared/Decentralized Sequencers: Espresso’s HotShot confirmation network gives rollups near‑instant, BFT‑backed pre‑confirmations across chains, improving UX and cross‑rollup bridging while L1 settlement happens later. Astria offers a 1‑second shared sequencing layer paired with Celestia DA for modular rollups. (docs.espressosys.com)

Sidechains: fast and cheap, but with different trust

Sidechains (e.g., Polygon PoS) have independent consensus, so they’re not limited by Ethereum’s blob capacity and fees are very low, but security and finality rely on the sidechain’s validator set and tooling.

Block time and fees: Polygon PoS generally targets ~2.1s blocks and sub‑cent fees; gas trackers often show fractions of a cent for common actions, though absolute $US depends on token price. (ww4.polygonscan.com)
Operational risk: When a sidechain’s consensus stalls or finality lags, UX suffers even if blocks keep ticking. In Sept 2025, PoS experienced 10–15 minute finality delays despite ongoing block production—an example of risk you must budget for in operational runbooks. (theblock.co)

When to pick a sidechain:

Consumer apps where absolute least cost matters, gas sponsorship is core to UX, and you can accept the chain’s sovereignty/trust model.
You’re content with bridges and security that do not inherit Ethereum L1 guarantees by default.

Purpose‑built real‑time settlement L1s: speed and price at base layer

These platforms are engineered for rapid finality and high throughput without an L2 hop. They shine for latency‑sensitive flows (trading, messaging, gaming, micropayments).

Representative platforms and concrete, operator‑relevant details:

Solana: Base fee is 5,000 lamports (0.000005 SOL) per tx; typical priority fees remain under $0.01 even in high demand. Commitment levels: processed ~sub‑second, confirmed ~1–2s, and finalized typically ~10–20s depending on network conditions. Firedancer (new C++ validator client) is rolling out to increase throughput and client diversity. (solana.com)
NEAR: As of May 2025, mainnet launched 600 ms blocks with ~1.2‑second finality (“optimistic blocks” in Nightshade 2.0), targeting further reductions. This is world‑class for real finality on a public chain. (pages.near.org)
Avalanche: Time‑to‑finality on the order of ~0.8 s on Avalanche L1s in the builder docs; recent gas‑target increases on the C‑Chain improved throughput headroom. (build.avax.network)
XRPL: Minimum fee for a standard tx is 10 drops (0.00001 XRP); ledgers close every ~3–5 seconds on average. Excellent for payment‑style flows. (xrpl.org)
Stellar: Ledgers close roughly every ~5 seconds; Soroban smart‑contract fees are resource‑metered with published CPU/memory/disk schedules, enabling precise gas budgeting. (developers.stellar.org)
Hedera: Fees are USD‑denominated (paid in HBAR), making budgeting straightforward. Note: Hedera announced the ConsensusSubmitMessage fee moves from $0.0001 to $0.0008 in January 2026—plan ahead if you rely on that primitive. (hedera.com)

What to internalize:

For high‑frequency microtransactions (ads, tips, in‑game events), the unit cost on these L1s is typically below 1/100th of a dollar—often much lower—and finality is seconds or less. You don’t manage batchers or blob prices; you do manage validator/client health and priority‑fee policies. (solana.com)

Concrete comparisons you can plug into planning

Below are practical back‑of‑napkin models you can adapt. Always sanity‑check with your own load tests.

Payments app: 1 million simple transfers/day, low latency UX

Solana: Base fee 0.000005 SOL/tx. At $100/SOL, that’s $0.0005 per tx → ~$500 per 1M transfers, excluding optional tiny priority fees. Finality typically under ~20s with sub‑second confirmations. (solana.com)
OP‑Stack rollup: Assume 10 bytes/tx post‑compression into blobs (varies by chain), blob lane at moderate prices; practical user fees often sub‑$0.01/tx post‑Dencun. If your average is $0.003, budget ~$3,000 per 1M transfers, but you can push lower with better compression and batch cadence. Settlement and withdrawal semantics still follow L1 timing. (thedefiant.io)

Real‑time exchange: sub‑second state changes and cross‑market risk

NEAR or Avalanche can give 1–2 s finality and high throughput at base layer; you avoid L2/L1 anchoring delays. Useful when “done in 2 seconds” is a product requirement. (pages.near.org)
On a rollup, users see fast sequencer acks, but your cross‑domain safety (bridges, liquidations) still respects L1 batch/settlement cycles. Consider a shared sequencer (Espresso) for seconds‑level cross‑rollup confirmations during settlement lag. (docs.espressosys.com)

Compliance‑sensitive integrations

Hedera’s USD‑fixed fees simplify budgeting and procurement (e.g., per‑API call costing), and predictable seconds‑level finality eases reconciliation. (hedera.com)

Why rollups still win for many enterprise builds

Ethereum security/composability: You inherit Ethereum’s validator/economic security and are “a bridge away” from the largest onchain liquidity and tooling.
Horizontal scale: You can launch multiple domain‑specific rollups; each scales in parallel and remains EVM‑compatible. DA bottlenecks are being expanded with PeerDAS (EIP‑7594) and future blob‑capacity bumps. (eips.ethereum.org)
Pre‑confirmations are getting real: Shared/decentralized sequencers cut the UX gap to seconds and make cross‑rollup intents safer. Espresso’s HotShot confirms in a few seconds and is designed to scale to many nodes. (docs.espressosys.com)

Key caveat: rollup throughput today is a function of bytes, not “TPS on a spec sheet.” Your engineering focus moves to compression, batching, and DA selection.

Emerging best practices to push throughput and drop fees

For rollups:

Tune batchers with intent: set max‑delay 5–15 minutes; align batch size thresholds with diurnal traffic to keep compression high yet post promptly. (docs.arbitrum.io)
Aggressive compression: benchmark brotli params on your actual calldata; instrument “compressed‑bytes per tx” and push that down ruthlessly. (research.arbitrum.io)
Consider Alt‑DA: pilot Celestia for large fixed‑rate data (logs, receipts) or EigenDA if you need higher aggregate MB/s; validate pricing and failure modes vs. Ethereum DA. (docs.celestia.org)
Ship shared sequencing: plug Espresso or Astria to provide seconds‑level confirmations and smoother cross‑chain UX. (docs.espressosys.com)
Budget for settlement finality: if withdrawals matter, model the 7‑day dispute window (optimistic) or proof verification time (ZK). Use bridging UX that surfaces “sequencer‑confirmed vs L1‑final” clearly. (docs.l2beat.com)

For sidechains:

Operational SLOs: write runbooks for delayed finality and RPC instability; design app UX (e.g., balances, order placement) to tolerate multi‑minute finality stalls. (theblock.co)
Monitor validator health and client versions like you would core infra.

For real‑time L1s:

Price stability: if your P&L is $‑denominated, consider Hedera’s USD‑fixed fees to avoid fee volatility; otherwise model token‑price sensitivity (e.g., SOL) against your unit economics. (hedera.com)
Throughput guardrails: don’t just trust “TPS” claims—understand block/slot timing, priority fee dynamics, and finality semantics for your specific chain and client version. (helius.dev)

Deep dive: numbers behind the choices

Ethereum DA math today: with a 12‑second slot, target 3 blobs (max 6), and 128 KiB per blob, your budget is roughly 32–64 KiB/s. If your average compressed L2 tx takes 60–120 bytes of blob data, you’re looking at hundreds to low thousands TPS across all rollups, system‑wide. Improvements like PeerDAS increase blob throughput without overburdening nodes by allowing sampling instead of full downloads. (eips.ethereum.org)
Avalanche’s TTF framing: the docs emphasize time‑to‑finality as a better KPI than raw TPS; the platform targets sub‑second finality with multi‑k TPS and can dial C‑Chain gas targets upward with upgrades like Octane. This matters because finality is what determines business UX certainty. (build.avax.network)
Solana fee micro‑profile: base 0.000005 SOL plus optional priority fee gives you predictable sub‑cent costs for common actions; you still manage commitment levels (processed/confirmed/finalized) to design the right UX checkpoints. (solana.com)
XRPL and Stellar fee/finality: XRPL’s 10‑drop minimum and ~3–5s ledger closures are ideal for payment rails; Stellar closes ~5s ledgers and publishes Soroban fee schedules, enabling precise cost simulation for smart‑contract calls. (xrpl.org)
Hedera’s budgeting advantage: USD‑fixed fees simplify procurement and per‑API unit economics; note announced 2026 price change for ConsensusSubmitMessage. (hedera.com)

When to choose what: a quick playbook

Choose a rollup (or your own app‑chain rollup) if:

You require EVM compatibility, Ethereum security, and want to launch multiple domains (payments, loyalty, gaming) with shared tooling.
You can tolerate settlement latency patterns (minutes for anchoring; days for optimistic finality) and can implement pre‑confirmation UX.
You plan to leverage Alt‑DA and shared sequencers to reach “real‑time enough” UX while preserving Ethereum alignment. (docs.espressosys.com)

Choose a sidechain if:

Absolute lowest fees and fast blocks matter most, and you accept separate consensus/trust and incident risk. You’ll build operational safety nets for delayed finality or RPC issues. (theblock.co)

Choose a purpose‑built real‑time L1 if:

Sub‑second to seconds‑level confirmations and pennies‑to‑sub‑pennies fees are a core product requirement (HFT UX, streaming payments, messaging), and you’re not anchored to Ethereum composability for your MVP. Solana, NEAR, Avalanche, XRPL, Stellar, Hedera all fit different regulatory and operational models; test with realistic load. (solana.com)

Implementation checklist (what we advise clients at 7Block Labs)

Define “real‑time”: choose commit level (soft vs final) and target latency in seconds. Codify in UX and SLAs. (helius.dev)
Cost guardrails: for rollups, monitor “compressed bytes per tx,” blob base fee, and batcher delay; for L1s, monitor token price × base/priority fee curves (or USD‑fixed schedules on Hedera). (research.arbitrum.io)
DA strategy: start with Ethereum blobs; model a migration path to Celestia/EigenDA if you hit DA ceilings or need predictable pricing at higher bandwidth. (docs.celestia.org)
Pre‑confirmations: integrate Espresso/Astria for seconds‑level cross‑rollup confidence and better bridging UX. (docs.espressosys.com)
Incident playbooks: if using sidechains, include finality lag and RPC brownouts in runbooks; if using rollups, include L1 reorg resistance settings and forced‑inclusion paths. (theblock.co)

Bottom line

Rollups are now cheap and horizontally scalable, with maturing tooling to make them “feel” real‑time—great when Ethereum alignment matters. But their sustainable throughput is still a function of bytes on Ethereum (today), and their hard settlement follows L1 cadence. (eips.ethereum.org)
Sidechains and purpose‑built real‑time L1s deliver speed and price at the base layer, which is unbeatable for latency‑critical, high‑volume flows—so long as you’re comfortable with their security and operational models. (solana.com)

If you share your target SLA (e.g., “users must see money ‘arrive’ in <2s” and “we can spend up to $0.002 per tx at 10M tx/day”), we’ll map it to a concrete architecture and run comparative load tests to validate both throughput and cost before you commit.