Rollups vs Sidechains Throughput Cost Comparison for High-Volume Apps

A Practical Guide to Choosing Between Rollups and Sidechains for High-Volume Apps

When you're dealing with apps that are racking up millions of transactions, picking between rollups and sidechains is a big deal. We’ve put together this number-driven guide to help you navigate that choice.

We'll dive into the benchmarks for throughput ceilings, break down the different fee components, and look at the real costs per million transactions after EIP-4844 went into effect. Plus, we'll explore how different Data Availability (DA) options--like Ethereum blobs, Celestia, and AnyTrust--affect the economics of each unit.

So, let’s get into it!

Who this is for

If you're a decision-maker at a startup or a larger enterprise and you're gearing up for high-volume payments, social platforms, gaming, or exchange workloads, you really can't afford any surprises when it comes to costs or capacity.

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Executive summary

• After EIP-4844, rollups that use Ethereum blobs can achieve impressive triple-digit TPS for more complex tasks and even hit four-digit TPS for straightforward transfers. However, it’s important to note that fees are mainly driven by blob data costs. If you switch up the data availability layer (like going to Celestia or AnyTrust), you could see L2 data costs drop dramatically--by two whole orders of magnitude--for workloads that are heavy on data. (eips.ethereum.org)
• On the other hand, sidechains like BNB Smart Chain and Polygon PoS offer strikingly low fees per transaction, along with high throughput. That said, they have different trust and security assumptions compared to Ethereum rollups. Right now, the average fees are hanging out in the cents-to-sub-cent range, and some of this can be influenced by policies in place (for example, BSC currently has a minimum gas fee of 0.05 gwei). (bscscan.com)

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1) The essential difference (only what matters for cost and TPS)

• Rollups, whether Optimistic or ZK, handle most of the action off-chain and then post the data for verification. Your fees break down like this:
  • L1 data costs (that’s calldata before the EIP-4844 update and blob data afterward).
  • Gas for executing on L2.
  • If you’re using ZK rollups, you’ll also cover proof generation and verification costs, but those are spread out over multiple transactions. (specs.optimism.io)
• Sidechains operate with their own consensus mechanisms and fee structures. Here, you only pay the gas fees of that particular chain; there’s no mandatory L1 data posting unless you specifically design it that way. Fees and capacity really depend on what the chain’s parameters are and how its validators operate. (bscscan.com)

When it comes to security trade-offs, here’s the gist: rollups benefit from Ethereum's data availability and settlement guarantees (especially if they tap into Ethereum DA), while sidechains introduce a bridging/trust layer along with their own validator set. For setups like “validium/AnyTrust,” data availability is handed over to a committee or an external DA layer to save some bucks, but that comes with a bit more trust on your part. (docs.arbitrum.io)

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2) Throughput headroom you can actually plan around

Think in terms of gas-per-second, and then map that to your transaction's gas profile.

• OP Stack reference (Base): It’s got a rate of 32.5M gas/sec. Here’s what that means:
  • About ~1,548 simple transfers per second (roughly 21k gas/tx).
  • Approximately ~162 DEX swaps per second (around 200k gas/tx). Check out the details over at docs.optimism.io.
• Arbitrum (currently under proposal/vote): They’re looking to bump the gas target up to 10M gas/sec. This would translate to:
  • Roughly ~476 transfers/sec or ~50 swaps/sec at that baseline target. You can find more info on this at forum.arbitrum.foundation.

Here's what the sidechain throughput looked like today (just a 24-hour snapshot, not the max values):

• BNB Smart Chain: Around 101.6 TPS in the last 24 hours, and fees have been pretty low. Check it out on bscscan.com.
• Polygon PoS: About 47.6 TPS over the last 24 hours, with fees usually around one cent lately. You can find more details on polygonscan.com.

What this means:

• If you’re looking to handle over 100 complex swaps per second, a Base-style OP chain has you covered right from the start. An Arbitrum chain can also get there, but it might take some tweaks to the parameters or splitting up the workloads. Sidechains can manage those big spikes, but keep in mind that you'll be sharing block space with the entire ecosystem. (docs.optimism.io)

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3) Fee components after EIP‑4844 (Proto‑Danksharding) and why they matter

EIP-4844 brought in these cool temporary “blobs” that come with their own fee market. These blobs stick around for about 18 days and are way cheaper per byte compared to calldata, which is a game changer for Layer 2 economics. Initially, the target capacity is set at 3 blobs per block, with a maximum of 6. Check it out here: (eips.ethereum.org).

Sure! Here’s a more relaxed version:

Rollup fee = L2 execution gas + L1 data fee (which is now blob-priced) + (if you’re using ZK) proving cost:

• OP Stack: The L1 data fee changes based on Ethereum’s blob base fee, and you can find the scalars in the SystemConfig after Ecotone. Check it out here: (specs.optimism.io).
• Arbitrum: To figure out the total fee, you take the L2 gas price and multiply it by the sum of L2 gas plus a buffer for the L1 data. The L1 price per byte is estimated and compressed (thanks to Brotli). The fee splits include the L1 base fee, the L2 base fee, and some surplus components. More info here: (docs.arbitrum.io).
• ZK rollups: Don’t forget to add in those proving costs. Right now, estimates suggest that proving costs are just a fraction of a cent per transaction at scale--and they’re expected to get better over time! Learn more at: (chorus.one).

Sidechains

When it comes to sidechains, there's just one L2-style fee that you pay to validators, and the price really varies based on the chain's policy and demand for gas. Here's what we're seeing on average right now:

• BNB Smart Chain: The average transaction fee is about $0.03 over the past 24 hours. Plus, there's a network-wide policy change coming in October 2025 that will drop the minimum gas price to 0.05 gwei, which could bring a lot of transactions down to around half a cent. Check out more details on bscscan.com.
• Polygon PoS: For Q1 2025, the average fee is sitting around $0.01 per transaction, with a lot of times actually being even lower. You can dive deeper into that over at messari.io.

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4) Data availability choices swing your unit economics

You can mix Ethereum settlement with a bunch of different DA backends:

• Ethereum Blobs (default, most secure): These use predictable logic, but keep in mind that costs can change based on the blob fee market. You can find useful info in stakeholder docs and dashboards, which show blob costs typically well below calldata. Expect these to shift a bit with demand. (eips.ethereum.org)
• Modular DA (Celestia) via OP Stack or Orbit integrations: If you're into data-heavy apps, this option is a game changer as it offers DA at a fraction of the cost. The combo of OP Stack with Celestia and Arbitrum Orbit with Celestia are solid production-ready choices, plus there's an Ethereum fallback for extra peace of mind. (blog.celestia.org)
• AnyTrust/validium-style (e.g., Arbitrum Nova or custom Orbit): In this setup, a committee takes care of DA while Layer 1 only sees the certificates, which can really cut down on on-chain data expenses. (docs.arbitrum.io)

Current Reference Points:

• Example Cost Model (OP Stack): We’re talking about 1,000,000 ERC‑20‑like transactions, each about ~120 bytes.
  • Posting to Ethereum (calldata/blobs): Roughly $78,558 for a million transactions.
  • Posting to Celestia: Just about $332 for a million transactions (that’s around 99.6% cheaper!). Check it out here: docs.gelato.cloud.
• When it comes to Celestia's data availability (DA) pricing, discussions are pointing to live prices in the low cents per MB, with some proposals suggesting a tiered volume pricing model. The bottom line? Celestia DA typically ends up being one to two orders of magnitude cheaper than Ethereum blobs, especially when you're pushing for sustained high throughput. For more insights, head over to forum.celestia.org.

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5) Practical, apples‑to‑apples cost examples

Here are the planning numbers you can use for a sanity check during due diligence. Feel free to replace them with your own transaction sizes and gas profiles.

A) Social app:

• We're looking at around 1,000,000 lightweight posts a day, with each post being about 120-150 bytes per transaction.
• Using the OP Stack rollup with Ethereum's data availability (DA), it's going to cost you around $78.6k per million posts (that's just the DA part), plus a small execution fee on Layer 2. If your posts hit that 150-byte mark, remember to add about 25% more to your calculations. Check out more details here.
• If you go with the OP Stack rollup and Celestia DA, the cost jumps to about $332 per million posts, but you're still on the same execution layer as the one mentioned above. For more info, visit this link.
• With Arbitrum AnyTrust (think Nova-style setup), you’re typically looking at costs that are an order of magnitude cheaper than full rollup DA. It does come with a bit of committee trust, though. Learn more about it here.
• On the Polygon PoS sidechain, expect to spend roughly $10,000 per million posts at around $0.01 on average. You can dive deeper into this here.
• For the BNB Smart Chain sidechain, you're looking at about $30,000 per million posts at an average fee of $0.03. But if the fees change to around 0.05 gwei, that could bring your costs down to roughly $5,000 per million. You can get more insights here.

B) Exchange: aiming for a steady 100 swaps per second (around 200k gas per transaction).

• OP Stack chain (similar to Base): With a solid capacity of 32.5M gas per second, you're looking at comfortably handling about 162 swaps per second. Just keep in mind that your main hurdles will be the costs of data availability and bidding priority fees when things get busy. (docs.optimism.io)
• Arbitrum with a target of 10M gas per second: This setup allows for roughly 50 swaps per second. If you want to hit that 100 mark, you might want to consider setting higher targets, splitting up the workload, or even spinning up a dedicated Orbit chain with some fine-tuning. (forum.arbitrum.foundation)
• Sidechains: Both BSC and Polygon show that their transactions per second can handle the workload pretty well. However, keep in mind that you’ll be sharing space with other network activities, and you'll trade off Ethereum-native settlement for some bridge assumptions. (bscscan.com)

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6) Finality and withdrawals: the hidden UX cost

• Optimistic rollups: When you're looking to withdraw to Ethereum, you’re typically stuck waiting about 7 days because of the challenge window. If you want to speed things up, there are fast-withdrawal services and commit tees that can cut down that waiting time, but you’ll need to trust them a bit more. So, if you're often jumping user balances back and forth to L1, keep that delay in mind when you're handling treasury and liquidity operations. (support.arbitrum.io)
• ZK rollups: The cool thing about ZK rollups is that your withdrawals wrap up as soon as the proofs get verified on L1--usually just a matter of minutes to under an hour if all goes well. It’s a good idea to check out the current parameters of your chosen ZK stack to get the latest on timing. (docs.zksync.io)

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7) Sidechain reality check (2025)

• BNB Smart Chain: If you're looking for a budget-friendly option, BNB Smart Chain is the way to go. It boasts super low fees and a daily throughput that's pretty impressive. Their aggressive fee-floor policy (0.05 gwei) can keep most simple transactions around $0.005! Lately, the average fee over a 24-hour period has been about $0.03. This makes it a solid choice for ultra-low-margin micro-transactions, but just keep in mind that this comes with BSC’s validator/security model. Check it out here: bscscan.com.
• Polygon PoS: Polygon has matured quite a bit over the years. In Q1 2025, the average transaction fee was hovering around $0.01. While the daily transactions per second (TPS) are more in the tens rather than the hundreds, they're continually rolling out upgrades that promise to push those limits. If you’re looking for a reliable ecosystem, this one’s a solid bet! More details can be found at messari.io.
• Gnosis Chain: Gnosis Chain offers sub-cent fees and has lower observed TPS. It’s often a go-to for payments and utility applications, especially if you’re leveraging Ethereum tooling. If you're interested, you can learn more here: chainspect.app.

Security Note: Bridge incidents were a major cause of crypto losses in 2022. If your assets rely on moving between a sidechain and Ethereum, make sure to set aside enough funds for better security, thorough audits, and a solid incident response plan. Check out more details here.

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8) Emerging best practices that materially cut your costs

• Pack blobs efficiently. Try to fill up those blobs before you post them--think batching, Brotli, and smart timing. The blob market charges you for every blob unit, so if you’re sending out half-empty blobs, you’re throwing away money in the long run. Check it out here: (docs.arbitrum.io)
• Choose DA based on workload tier:
  • Stick with Ethereum blobs for those high-stakes DeFi projects or when you need rock-solid L1 guarantees.
  • For chatty, low-stakes, or social data, go with Celestia/EigenDA or AnyTrust to save a boatload--like 10 to 100 times your costs.
  • And don’t forget to have Ethereum as a backup if your preferred modular DA goes down. More info here: (blog.celestia.org)
• Tune gas targets and floors:
  • On Arbitrum, bump up your gas target (like from 7M to 10M gas/sec) to increase your capacity. Plus, set a minimum L2 base fee to keep the spam at bay and smooth out those price swings. More details here: (forum.arbitrum.foundation)
  • For the OP Stack, consider using Flashblocks/Rollup Boost to achieve those lightning-fast sub-second block times when user experience is on the line. Just make sure your DA/posting pipeline can handle the pressure. Check it out: (docs.optimism.io)
• Understand priority fees. On bustling L2s, a small number of addresses can rake in most of the priority fee revenue. So, it’s a good idea to create fair-ordering or auction strategies in your app to dodge those crazy bidding wars. Dive deeper here: (coinlaw.io)
• For ZK stacks, keep an eye on proving costs. The costs associated with hardware and prover upgrades are generally trending down, which means you might want to re-evaluate those per-transaction proof costs quarterly. Get the full scoop here: (chorus.one)

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9) Decision guide: when rollup vs sidechain makes financial sense

Go for an Ethereum rollup (Ethereum DA) if you:

• Are holding onto high-value assets or need that sweet Ethereum-native composability.
• Don’t mind waiting around for about a week for those optimistic withdrawals (or if you want quicker exits, consider a ZK rollup).
• Find that your data availability budget with blobs makes sense compared to sidechains. Check it out here: (eips.ethereum.org)

Pick an Ethereum rollup that uses modular DA (like Celestia or EigenDA) or AnyTrust if:

• Your application sends a ton of small messages (think social media updates, gaming state changes, or receipts).
• You want Ethereum to handle settlement but at way lower DA costs. You’re cool with a bit of trust assumption for DA or using an external DA layer. Check out this blog post for more info!

Choose a Sidechain If:

• You need super low fees--like sub-cent fees right now--and you’re okay with the validator and bridge setup that comes with the sidechain.
• You’ve got a game plan to tackle bridge risk (for example, keeping custody on-chain only for a short while or using exchanges and fiat on/off ramps to steer clear of hot bridges for your end-users). Check out this chart on BscScan for more details.

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10) Brief in‑depth notes on how to scope your own cost model

• Profile Your Transactions:
  • Check out the average bytes per transaction (after compression) and the average L2 gas per transaction.
  • For swaps or mints, grab some gas data from those busy peak times.
• Convert to Blob/DA Costs:
  • With Ethereum blobs, figure out the cost per megabyte based on your target blob base fee. Don't forget to stress-test this with increases of 2-5 times!
  • For Celestia or AnyTrust, tap into provider quotes and make sure to factor in your quorum and retention needs. (forum.celestia.org)
• Add Execution and (if ZK) Proving Costs:
  • You'll want to calculate execution gas multiplied by the L2 base fee, then add in the amortized proof cost. Also, keep a separate line for sequencer margin and priority fees during those busy times. (docs.optimism.io)
• Simulate 3 Loads:
  • Quiet: 10% of peak.
  • Nominal: Your average day.
  • Surge: The top 5% busiest hour.

Typically, just one spreadsheet tab featuring these four lines (DA, execution, proving, priority) can help us nail down the right architecture in a single workshop.

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What 7Block Labs recommends in 2025

• If you're working on consumer-scale chatty apps, you'll want to go with OP Stack or Orbit along with Celestia DA (and don't forget to enable Ethereum fallback). This combo keeps data availability under $1k for every million events while still using Ethereum for settlement. It's a good idea to kick things off with one chain per product tier to keep those priority fees in check. Check out more details here.
• For mid to high-value DeFi projects, start with Ethereum's data availability. Also, consider putting together a “DA switch” runbook with some governance guardrails. This way, you can easily switch to Ethereum calldata or blobs if there are any hiccups with third-party DA services. You can find more info on this here.
• If cost is a big concern and your on-chain value is limited, BNB Smart Chain or Polygon PoS are smart choices. Just make sure to wrap any bridge exposure with custodial or delayed-settlement patterns to keep things safe. More details can be found here.

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Sources for the numbers referenced

• EIP‑4844 blobs: They’ve got a fresh capacity and pricing model, plus these blobs hang around for about 18 days. Check it out here.
• OP Stack: This is all about throughput and data availability options, including Flashblocks and Rollup Boost. Dive into the details here.
• Arbitrum AnyTrust/DA model: Here’s the scoop on their fee breakdown and a new gas target proposal shooting for 10M gas/sec. More info can be found here.
• Celestia DA: They’ve got some context on pricing, integration with the OP Stack, and some cost differences when handling 1M transactions. You can read more here.
• Sidechain fees and throughput: Get a snapshot of what’s happening with fees and throughput on BscScan and PolygonScan/Messari. Check it out here.
• Optimistic withdrawal windows: Let’s talk about the tradeoffs of fast withdrawals and why there’s a wait time. You can find the details here.
• Bridge risk background: This gives you some context to understand sidechain decisions a bit better. Check out the full story here.

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If you're looking to benchmark your specific workload--like payload sizes, compression ratios, or burstiness--against OP Stack/Orbit, Celestia/EigenDA, and the big sidechains, just get in touch with 7Block Labs. We’ll provide you with a one-page total cost curve along with any migration triggers you might need.