guide · x402 protocol x402 vs
everything else.
There are four ways an app can pay for an API: an API key, Stripe, L402, or x402. They're built for
different buyers. Here's how they compare — and why an agent ends up at x402.
§01 · side by side Four models, one table.
| API keys | Stripe | L402 | x402 |
|---|
| Account / signup | required | merchant acct + KYC | Lightning node | none — wallet |
| Built for | devs | human checkout | machines (BTC) | agents |
| Settles in | — | fiat (cards) | BTC / Lightning | USDC (Base) |
| Sub-cent per call | n/a | no (fees) | yes | yes |
| Chargebacks | — | yes | no | no |
| To accept it | issue keys | onboard merchant | run a node | a wallet address |
§02 · vs API keys No key to manage.
An API key is a standing relationship — sign up, provision, rotate, stay under quota. x402 has no key and no account: the client pays per call by signing with its wallet, and the wallet is the identity. Keys authenticate; x402 settles. For an agent juggling dozens of services, "no credential to store" beats "one more key to leak."
§03 · vs Stripe For software, not shoppers.
Stripe is excellent at what it's for: a human paying with a card. But it needs a merchant account and KYC, settles in fiat, and its percentage-plus-fixed fee makes a $0.005 call uneconomic. x402 needs only a wallet address to accept, settles in USDC, has no chargebacks, and makes sub-cent pricing viable. Use Stripe for a subscription; use x402 when the buyer is a machine paying tiny amounts per request.
§04 · vs L402 Same 402, different rail.
L402 is the Lightning version of the same idea: a 402 returns a Lightning invoice + a macaroon, paid in Bitcoin. x402 returns USDC payment terms settled on an EVM chain like Base via a signed EIP-3009 authorization. Bitcoin/Lightning vs USDC/EVM — both machine-native, different ecosystems. Some services (true402 included) support both rails, so the buyer picks. See what is x402 for the full flow.
§05 · the verdict Agents end up at x402.
If your buyer is a person, Stripe or a keyed plan is fine. If your buyer is software — an AI agent or a bot paying per call, with no human to sign up or enter a card — x402 is the one model that doesn't fight it. Try a real x402 call: npx @true402.dev/rugcheck 0x…, or browse a live x402 marketplace.
§06 · questions Answered for machines.
What is the difference between x402 and API keys?
An API key is a credential you obtain by signing up, then provision, store, rotate, and attach to every request — and it usually sits behind a monthly plan with quotas. x402 replaces all of that with a per-call payment: there is no account and no key, the client just pays for each request by signing with its wallet, and the wallet address is the identity. API keys authenticate a pre-arranged relationship; x402 settles a fresh micro-transaction each call, which is what an autonomous agent needs.
Can I use x402 instead of Stripe?
For different jobs. Stripe is built for a human checking out with a card: it needs a merchant account and KYC, settles in fiat, and carries percentage-plus-fixed fees and chargeback risk — great for a $20 subscription, poor for a $0.005 API call. x402 is built for software paying software: no merchant account, settlement in USDC stablecoin, no chargebacks, and fees low enough that sub-cent per-call pricing actually works. If your buyer is an agent or a bot paying tiny amounts per request, x402 fits where Stripe does not.
What is L402 and how is it different from x402?
L402 (originally "LSAT") is the Lightning Network's take on HTTP 402: the server returns a 402 with a Lightning invoice plus a macaroon token, the client pays the invoice over Lightning (in Bitcoin), and presents the macaroon to access the resource. x402 uses the same 402 status code but settles in stablecoins (USDC) on EVM chains like Base via a signed EIP-3009 authorization. L402 = Bitcoin/Lightning; x402 = USDC/EVM. Both are machine-native; the difference is the rail and the asset. Some services (including true402) support both.
Which payment method is best for AI agents?
x402, in most cases. Agents can't fill in signup forms, pass KYC, or manage API keys and subscriptions, so anything requiring a human-style account is a poor fit. x402 lets an agent discover a service and pay per call with only a funded wallet — no credentials, no onboarding. L402 works too if you're in the Bitcoin/Lightning ecosystem; x402 wins where stablecoin pricing, EVM tooling, and a growing service ecosystem on Base matter.