TypeScript API surface

Generated from the built tx402 package’s own exports, so this list cannot claim a symbol the package does not ship. Signatures and per-symbol documentation live in the bundled .d.ts files, which your editor reads directly — this page answers “what is available and from where”.

`tx402` — the core entry point

Importing this path must not load a chain library, and a package-contract test asserts it. viem, @solana/kit, @x402/evm, and @x402/svm are reached through a lazy import() only when a payment on that family is actually planned.

Functions

assertValidReleaseManifest
chainFamily
createBalanceProbeCache
createTx402Client
decodePaymentRequired
digestRequestBody
fingerprintRequest
formatMoneyDecimal
isEvmSigner
isSolanaSigner
isTx402Error
normalizeFingerprintUrl
normalizePolicyHost
orderRouteCandidates
parseMoneyAtomic
parsePositiveMoneyAtomic
planRoutes
requireNetwork
resolveNetwork
verifyReleaseManifest

Classes and constructors

AmbiguousPaymentError
BudgetExceededError
ClockSkewError
ConfigurationError
DomainNotAllowedError
HealthIndex
InsufficientLiquidityError
InvalidPaymentRequiredError
MemorySpendStore
MoneyParseError
NonReplayableRequestError
PaidRedirectBlockedError
PolicyEngine
RecipientUnpinnedError
ReservedHeaderError
ResourceDeliveryError
SignerError
SpendScopeFrozenError
TransportError
Tx402Error
UnsupportedProtocolError
UnsupportedSchemeError

Constants

BALANCE_KEY_SEPARATOR
BALANCE_TIMEOUT_MS
BUNDLED_MANIFEST
CIRCUIT_OPEN_MS
EVENT_NAMES
HEALTH_CONSECUTIVE_FAILURES_TO_OPEN
HEALTH_EWMA_ALPHA
HEALTH_FAILURE_RATE_TO_OPEN
HEALTH_FAILURE_WINDOW
HEALTH_IDLE_RETENTION_MS
HEALTH_LATENCY_PENALTY_MAX
HEALTH_LATENCY_REFERENCE_MS
HEALTH_MAX_ENDPOINTS
HEALTH_MIN_SAMPLES_FOR_RATE
HEALTH_NEW_ENDPOINT_SCORE
HEALTH_OPEN_MS
MANIFEST_SIGNING_DOMAIN
MAX_AUTHORIZATION_SECONDS
MAX_PAYMENT_REQUIRED_BYTES
MAX_PAYMENT_REQUIRED_DEPTH
MAX_PAYMENT_REQUIREMENTS
MAX_PROVIDERS_PER_NETWORK
PACKAGE_NAME
PACKAGE_VERSION
PROJECT_URLS
PROTOCOL_HEADERS
REQUEST_FINGERPRINT_DOMAIN
REQUEST_ID_HEADER
RESERVATION_TTL_MS
RESERVED_REQUEST_HEADERS
ROLLING_WINDOW_MS
TRUSTED_MANIFEST_KEYS
TX402_ERROR_CODES
TX402_ERROR_DESCRIPTORS
TX402_ERROR_TAXONOMY
X402_PROTOCOL_VERSION

The client itself

createTx402Client(config) returns an object carrying these methods. They are read from a constructed instance, so this list cannot claim a method the package does not ship.

inspect(input: Tx402RequestInfo, init?: Tx402RequestInit): Promise<PaymentInspection>
plan(input: Tx402RequestInfo, init?: Tx402RequestInit): Promise<PaymentPlan>
fetch(input: Tx402RequestInfo, init?: Tx402RequestInit): Promise<Response>
getBudgetState(): BudgetState
queryBudgetState(query: BudgetQuery): Promise<BudgetState>
resetHealth(): void

fetch is the one most code calls. The other five are what you reach for when a payment has to be reasoned about rather than simply made: plan answers “what would this cost” without signing or reserving, inspect returns the raw challenge, and getBudgetState / queryBudgetState read the spend ledger — the latter for any scope, including one written by another process. Reconciling a settlement from code starts with plan and ends with queryBudgetState.

Optional subpath exports

Import	Loads	Use when
`tx402/evm`	`viem`, `@x402/evm`	You pay on an EVM network and want the bundled adapter.
`tx402/solana`	`@solana/kit`, `@x402/svm`	You pay on Solana and want the bundled adapter.
`tx402/signers`	`viem/accounts`, and `@solana/kit` lazily	Development only. `privateKeyToEvmSigner` wraps a raw hex key as an `EvmSigner`; `keypairToSolanaSigner` wraps a keypair as a `SolanaSigner`.

The Python package mirrors this split with extras: pip install tx402 is the core, tx402[evm], tx402[svm], and tx402[all] add the chain libraries. import tx402 loads no chain library in either language.