Arc vs Plasma for builders: two stablecoin L1s, two different fee philosophies

Plasma and Arc are both purpose-built Layer 1s for stablecoin payments, both EVM-compatible, and that's largely where the resemblance ends. Plasma is live — its mainnet beta launched with a reported $2 billion in liquidity on day one — and its signature feature is free USDT transfers subsidized at the protocol level. Arc is pre-mainnet until 16 September 2026 and builds its fee model around USDC as the native gas asset, not around subsidizing one specific stablecoin's transfers. As of 2 September 2026, one is running in production; the other is two weeks from its first real transaction.

What Plasma is, confirmed

Plasma is "a purpose-built blockchain designed to make stablecoin payments fast, reliable, and low-cost at global scale" (plasma.org). It's EVM-compatible, runs its own consensus mechanism called PlasmaBFT, and uses XPL as its native token for staking and for paying transaction fees outside its subsidized-transfer feature (Plasma documentation). The chain's headline mainnet claim is a launch with $2 billion in liquidity already committed on day one, though Plasma's public materials don't specify an exact mainnet launch date in the pages Built on Arc reviewed.

Plasma's most distinctive feature, and the one that most directly answers the "fee model" question a builder actually cares about, is zero-fee USDT transfers: sending USD₮ over what Plasma calls its own routes is free, with the chain's own site noting that "third-party fees may apply" for anything outside that direct path (plasma.org). The exact protocol mechanism — how the subsidy is funded and rate-limited — isn't detailed in Plasma's public-facing pages as of this writing; that's not yet confirmed at the implementation level, though the feature itself is a stated, live product claim, not a roadmap item.

Beyond the payments chain itself, Plasma has built a consumer-facing product, Plasma One, offering a Visa-branded card for spending stablecoin balances, cross-border transfers, cashback up to 4%, and yield up to 6% on balances, live on iOS and Android and usable in 180-plus countries where Visa is accepted.

What Arc is, for contrast

Arc is Circle's stablecoin-native Layer 1, public-testnet-live since 28 October 2025, mainnet scheduled 16 September 2026. Gas is paid in USDC at the protocol level (an EIP-1559-style base fee, 18 decimals), with a paymaster system that can extend fee payment to other stablecoins. Consensus is Malachite, a Tendermint-based BFT engine targeting roughly 780ms finality across a permissioned validator set of around 100 institutions, with 1MB blocks. The execution layer is EVM — Solidity, MetaMask, and standard Ethereum tooling all apply.

Fee philosophy: subsidize one stablecoin, or price all stablecoins natively

This is the real design fork between the two chains, and it's worth being precise about it rather than collapsing it into "both are cheap."

Plasma's approach is targeted subsidy: USDT transfers on Plasma's own routes are free, full stop, which is a strong, simple pitch for any product whose volume is overwhelmingly USDT-denominated — remittance corridors and retail cross-border transfer being the clearest fit, which lines up with Plasma One's own product design. Anything that isn't a plain USDT transfer on Plasma's native routes pays fees in XPL or faces third-party costs the chain doesn't control.

Arc's approach is native pricing in a single reference stablecoin across the board: USDC is the base gas asset for everything, not subsidized for one token type over another, with the paymaster layer available to extend fee payment (not free transfers) to other stablecoins. There's no equivalent "one stablecoin transfers free" feature on Arc as currently specified — Arc's pitch is predictable, dollar-denominated pricing for all activity, not a zero-cost lane for a specific asset.

For a builder, the practical question is which better matches the product: a remittance or retail-payout app moving mostly USDT benefits directly from Plasma's subsidy model in a way Arc doesn't replicate. A product that needs predictable USDC-denominated pricing across a mix of transaction types, without betting the fee model on one token's subsidized lane, fits Arc's design more naturally — once Arc is actually live to test that claim against.

There's also a forecasting difference worth naming. A subsidy lane is a policy choice a chain operator can adjust — Plasma could in principle narrow or widen what qualifies as a free route as usage patterns change, since the subsidy is a design decision layered on top of the base fee market rather than a fixed protocol constant. USDC-native gas pricing on Arc doesn't carry that same adjustable-subsidy variable: the fee a transaction pays tracks the base-fee mechanism directly, with no separate "which transfers qualify for the free lane" policy sitting in between. Neither is inherently more durable than the other — they're just different levers a builder is trusting the chain to manage predictably over time.

Architecture and validator model

Both chains are EVM-compatible Layer 1s with their own BFT-family consensus — Plasma's PlasmaBFT and Arc's Malachite are both Tendermint-lineage designs, which is a meaningful similarity for a builder estimating finality behavior. Where they differ is validator composition: Arc's set is explicitly permissioned and institutional — eleven founding validators including BlackRock, DTCC, Mastercard, and Visa, disclosed by Circle on 5 August 2026. Plasma's public documentation reviewed here references validator and non-validator node types without disclosing whether the validator set is permissioned or permissionless, or how many validators are active — that specific detail is not yet confirmed as of 2 September 2026.

That gap matters for the counterparty and compliance axis this cluster cares about. A builder or counterparty evaluating Arc can point to a named, public list of institutional validators. A builder or counterparty evaluating Plasma's validator composition as of this writing cannot get the same level of public specificity from Plasma's own documentation.

Which fits which job

A builder shipping a remittance, payout, or retail cross-border product where USDT is the dominant settlement asset has a genuinely strong, live, tested option in Plasma today — the zero-fee transfer lane and the Plasma One consumer product are shipped, not promised. A builder whose product needs USDC-native pricing across varied transaction types, or needs to point counterparties to a named, institutional validator cohort for compliance purposes, has a case to wait for Arc's 16 September mainnet, with the standing caveat that nothing about Arc's live performance is verifiable in public yet. Built on Arc doesn't rank the two — they're solving overlapping but distinct problems with genuinely different fee philosophies.

For the fuller field of purpose-built stablecoin chains, including how Tempo and Codex fit around Arc and Plasma, see Built on Arc's stablecoin chains compared hub.

Built on Arc is an independent directory. Arc is a Circle product; we are not affiliated with, endorsed by, or operated by Circle.

Sources: - Plasma — official site - Plasma documentation index - CoinGecko: Plasma (XPL) - Circle Announces Founding Validator Cohort and Major Integrations for Arc