Zero Fees, Infinite Complexity: Building Gasless Transactions at Scale

Blockchain infrastructure offers instant settlement, global reach, and cost structures that beat traditional finance by orders of magnitude. Stablecoins on modern L2s settle in under a second for less than a cent. The rails exist, but companies trying to take advantage of this next generation of money movement face a major challenge.

The adoption bottleneck is not speed, cost, or security — it's gas. Every blockchain transaction requires the sender to hold the chain's native token to pay fees. A user with $100,000 in USDC cannot send a single dollar without first acquiring ETH on an exchange. Gas prices fluctuate unpredictably. Different chains require different native tokens.

For financial institutions, this is a non-starter. Banks do not want to hold volatile native tokens on their balance sheets. Payment processors cannot ask end users to manage gas balances. Consumer apps cannot introduce multi-token complexity into flows that need to feel like Venmo.

Gasless transactions solve this by letting the application sponsor gas on behalf of users. The user never holds, acquires, or thinks about native tokens. The developer pays in USD. The infrastructure provider handles everything in between.

How Gasless Transactions Work

A gasless transaction shifts gas payment from the end user to the application developer, with the infrastructure provider managing the onchain mechanics and billing.

The flow:

1. Developer creates a gas policy — configures spending rules (per-user caps, per-policy limits), allowlists/blocklists, custom webhook-based eligibility rules, and ERC-20 token payment options via API or dashboard.

2. User initiates a transaction — the application forwards it to Alchemy's Transaction API.

3. Alchemy validates against the policy — checks spending limits, eligibility rules, and custom conditions in real-time.

4. Alchemy signs a paymaster payload — the Sponsorship Service generates a cryptographic signature via AWS KMS authorizing the onchain paymaster contract to pay gas.

5. Transaction lands onchain — the paymaster smart contract verifies the signature and fronts gas in native tokens.

6. Developer receives a USD invoice — Alchemy tracks the confirmed transaction, converts the gas cost to USD, and adds it to the monthly bill.

One API call. Minutes to integrate. The underlying infrastructure handles policy enforcement, cryptographic signing, multi-chain gas estimation, onchain confirmation tracking, and billing reconciliation.

The Infrastructure Under the Hood

Alchemy's gasless infrastructure consists of three core services:

Sponsorship Service — the real-time decision engine. Validates every sponsorship request against the developer's policy configuration, checks near-real-time aggregated spend stats, and signs paymaster payloads via AWS KMS with hardware-level security guarantees.

Paymaster Admin Service — CRUD APIs for creating and managing gas policies. Supports spending rules, allowlists/blocklists, custom webhook-based eligibility, ERC-20 token payment configuration, and policy duration controls.

Bundler — aggregates sponsored UserOperations (transactions) and submits them onchain as bundled transactions, optimizing for faster confirmation times and higher throughput. Handles submission strategies across supported networks, monitors for onchain inclusion, and feeds confirmation data to downstream billing and policy enforcement systems.

Together, these services process thousands of sponsorship requests per second across every supported chain, backed by 600M+ records and growing, with write throughput of 800/s and growing. All developers have to do is make a single API call.

What it takes to make gas invisible

Every infrastructure team faces build vs. buy. Our bar is simple: if it doesn't differentiate your product, you shouldn't be building it. Nobody picks a payment app because of how it sponsors gas, and the resourcing and time it takes to build gasless infrastructure is significant. Here’s a look behind some of the problems we solve so our customers don’t have to.

The Data Pipeline Problem

Every sponsorship request generates a record that must be written, tracked through onchain confirmation, and reconciled against billing. At scale, this becomes a high-throughput data pipeline challenge.

World sends 3.5 million sponsorship requests per day. At 3-month retention, that single customer generates hundreds of millions of records. Alchemy's paymaster database handles 800 writes per second across 600M+ total records, with infrastructure designed to scale to billions — tiered retention, streaming-based chain monitoring, and horizontal scaling across the service layer.

Real-Time Policy Enforcement

When a developer configures a policy limiting sponsorship to $100 per user per month, that limit must hold across every chain, every transaction, at thousands of requests per second. The source of truth for confirmed spend lives onchain and takes minutes to finalize, requiring continuous aggregation pipelines that reconcile offchain policy decisions against onchain finality in near-real-time.

Alchemy runs these pipelines continuously so that when a user hits their configured cap, sponsorship stops — even across simultaneous transactions on multiple chains.

Cryptographic Signing at Throughput

Every sponsored transaction requires a cryptographic signature proving the onchain paymaster contract should pay gas. Alchemy generates these via AWS KMS with hardware-level security — the same standard used by banks and government agencies.

Maintaining that security bar at high throughput requires horizontal key management strategies, low-latency signing pipelines, and redundancy ensuring no single point of failure blocks a transaction.

Multi-Chain Gas Abstraction

Gas mechanics differ significantly across chains. Ethereum L1 gas prices fluctuate with demand. L2s have different sequencer economics. Solana uses an entirely different model — sponsoring transaction fees and rent for associated token accounts rather than smart account paymasters.

Alchemy abstracts all of this behind a single API surface. Developers call prepareCalls with a policy ID, and the system handles chain-specific gas estimation, sponsorship validation, and onchain verification. Same developer experience across Ethereum, Arbitrum, Base, Solana, and every other supported chain.

Simple USD Billing

Developers should not need to hold ETH, SOL, or any native token to sponsor gas. Alchemy fronts gas in native tokens on every chain and delivers a single USD invoice at the end of the month.

This requires managing gas treasury across dozens of chains, real-time cost conversion to USD, and billing pipelines that accurately reconcile millions of sponsored transactions. Automatic spending caps protect against gas price spikes during congestion events, ensuring developers are never surprised by their bill. The result is SaaS-like billing experiences for something inherently volatile and multi-currency.

Protocol Evolution

The standard for gasless transactions on EVM has evolved significantly. ERC-2771 (meta-transactions) required modifying smart contracts. ERC-4337 introduced Account Abstraction with standardized Bundlers and Paymasters. EIP-7702 allows existing EOAs to gain smart wallet capabilities without migrating addresses.

Alchemy has built through every one of these transitions and designed its Transaction API as a capabilities layer rather than a protocol wrapper. The API expresses what developers want — sponsor gas, batch calls, accept ERC-20 gas payment — and handles the underlying protocol complexity. If a newer standard arrives or protocols shift, we adopt or adapt. Developer integrations don't change.

Developer Simplicity

The developer-facing integration is one API call:

Behind this: policy validation, real-time spend enforcement, chain-specific gas estimation, 7702 delegation detection, KMS signing, UserOperation construction, bundler submission, onchain confirmation monitoring, and billing reconciliation.

The same prepare-sign-send pattern works across any language and integrates with existing custody solutions (HSM, MPC, Privy, Turnkey) without architectural rewrites.

Market Context

Gasless transaction infrastructure is becoming a requirement across two converging markets:

Financial institutions entering crypto. Banks, fintechs, and payment companies cannot hold native tokens on their balance sheets. JPMorgan processes $10B+ daily in JPMD deposit token flows. Bank of China Hong Kong is deploying gasless infrastructure for stablecoin mint/burn operations. These institutions need production-grade gas sponsorship with compliance controls, audit trails, and SLA guarantees.

Consumer applications demanding invisible blockchain. Slash has processed $1B+ in stablecoin business payments with fully gasless flows. World runs 12M+ weekly transactions through Alchemy's bundler and paymaster infrastructure. The bar for user experience is instant, fee-free, and indistinguishable from traditional fintech.

Alchemy currently holds approximately 85% market share in gasless transactions across all EVM chains and Solana, with $1B+ processed over the past two years.

Building on Gasless Infrastructure

Managing paymaster infrastructure, KMS signing, multi-chain gas estimation, and protocol migrations does not differentiate a product. Users never know or care how their gas got sponsored — they know that sending money was fast, cheap, and easy.

Alchemy handles the infrastructure complexity so teams can focus on what moves their business: shipping features, growing users, and generating revenue. The best gasless transaction experience is the one nobody notices.

Explore gasless infrastructure, start building, and contact us for custom pricing, integration questions, and more. We're here to help!