Kernel is ZeroDev's modular ERC-4337 and EIP-7702 smart-account implementation. The TypeScript Kernel SDK (built on viem / permissionless) builds and signs UserOperations, then drives the bundler and paymaster RPCs. Kernel v3 supports EIP-7702 delegation alongside classic 4337 deployment.
openapi: 3.0.1
info:
title: ZeroDev Bundler & Paymaster RPC
description: >-
OpenAPI description of ZeroDev's account-abstraction infrastructure. ZeroDev
does NOT expose a REST API; the bundler and paymaster are JSON-RPC 2.0
services accessed by HTTP POST to a single project-scoped URL of the form
https://rpc.zerodev.app/api/v3/{projectId}/chain/{chainId}. The same URL
serves both the ERC-4337 bundler methods (eth_sendUserOperation,
eth_estimateUserOperationGas, eth_getUserOperationByHash,
eth_getUserOperationReceipt, eth_supportedEntryPoints, eth_chainId) and the
paymaster methods (zd_sponsorUserOperation, pm_sponsorUserOperation, the
ERC-7677 pair pm_getPaymasterStubData / pm_getPaymasterData, and
zd_getERC20PaymasterAddress). Authentication is by the projectId embedded in
the URL path. This document models that single JSON-RPC endpoint; the RPC
method is selected via the "method" field of the request body, not via the
HTTP path. Append ?provider=ULTRA_RELAY to route through ZeroDev UltraRelay.
termsOfService: https://zerodev.app/terms
contact:
name: ZeroDev
url: https://zerodev.app
version: '3.0'
servers:
- url: https://rpc.zerodev.app
description: ZeroDev meta-infrastructure RPC host
paths:
/api/v3/{projectId}/chain/{chainId}:
post:
operationId: jsonRpc
tags:
- JSON-RPC
summary: ZeroDev bundler & paymaster JSON-RPC endpoint
description: >-
Single JSON-RPC 2.0 endpoint. POST a request envelope whose "method"
selects an ERC-4337 bundler method or a ZeroDev/ERC-7677 paymaster
method. The projectId path parameter authenticates the call; the chainId
path parameter selects the target EVM chain (e.g. 1 Ethereum, 8453 Base,
42161 Arbitrum, 84532 Base Sepolia).
parameters:
- name: projectId
in: path
required: true
description: ZeroDev project ID from the dashboard; acts as the API credential.
schema:
type: string
- name: chainId
in: path
required: true
description: Numeric EVM chain ID of the target network.
schema:
type: integer
- name: provider
in: query
required: false
description: Optional underlying provider override (e.g. ULTRA_RELAY).
schema:
type: string
requestBody:
required: true
content:
application/json:
schema:
$ref: '#/components/schemas/JsonRpcRequest'
examples:
eth_sendUserOperation:
summary: Submit a UserOperation (bundler)
value:
jsonrpc: '2.0'
id: 1
method: eth_sendUserOperation
params:
- sender: '0x1234567890123456789012345678901234567890'
nonce: '0x0'
callData: '0x'
callGasLimit: '0x88b8'
verificationGasLimit: '0x33450'
preVerificationGas: '0xc350'
maxFeePerGas: '0x59682f00'
maxPriorityFeePerGas: '0x3b9aca00'
signature: '0x'
- '0x0000000071727De22E5E9d8BAf0edAc6f37da032'
eth_estimateUserOperationGas:
summary: Estimate gas for a UserOperation (bundler)
value:
jsonrpc: '2.0'
id: 1
method: eth_estimateUserOperationGas
params:
- sender: '0x1234567890123456789012345678901234567890'
nonce: '0x0'
callData: '0x'
signature: '0x'
- '0x0000000071727De22E5E9d8BAf0edAc6f37da032'
eth_getUserOperationReceipt:
summary: Fetch a UserOperation receipt (bundler)
value:
jsonrpc: '2.0'
id: 1
method: eth_getUserOperationReceipt
params:
- '0xdead00000000000000000000000000000000000000000000000000000000beef'
eth_supportedEntryPoints:
summary: List supported EntryPoint contracts (bundler)
value:
jsonrpc: '2.0'
id: 1
method: eth_supportedEntryPoints
params: []
zd_sponsorUserOperation:
summary: ZeroDev gas sponsorship (paymaster)
value:
jsonrpc: '2.0'
id: 1
method: zd_sponsorUserOperation
params:
- chainId: 8453
userOp:
sender: '0x1234567890123456789012345678901234567890'
nonce: '0x0'
callData: '0x'
signature: '0x'
pm_sponsorUserOperation:
summary: Pimlico-compatible sponsorship (paymaster)
value:
jsonrpc: '2.0'
id: 1
method: pm_sponsorUserOperation
params:
- sender: '0x1234567890123456789012345678901234567890'
nonce: '0x0'
callData: '0x'
signature: '0x'
- '0x0000000071727De22E5E9d8BAf0edAc6f37da032'
pm_getPaymasterStubData:
summary: ERC-7677 stub paymaster data (paymaster)
value:
jsonrpc: '2.0'
id: 1
method: pm_getPaymasterStubData
params:
- sender: '0x1234567890123456789012345678901234567890'
nonce: '0x0'
callData: '0x'
- '0x0000000071727De22E5E9d8BAf0edAc6f37da032'
- '0x2105'
- {}
pm_getPaymasterData:
summary: ERC-7677 final paymaster data (paymaster)
value:
jsonrpc: '2.0'
id: 1
method: pm_getPaymasterData
params:
- sender: '0x1234567890123456789012345678901234567890'
nonce: '0x0'
callData: '0x'
- '0x0000000071727De22E5E9d8BAf0edAc6f37da032'
- '0x2105'
- {}
zd_getERC20PaymasterAddress:
summary: Resolve the ERC-20 paymaster address (paymaster)
value:
jsonrpc: '2.0'
id: 1
method: zd_getERC20PaymasterAddress
params:
- entryPoint: '0x0000000071727De22E5E9d8BAf0edAc6f37da032'
gasToken: '0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913'
eth_chainId:
summary: Return the chain ID (bundler)
value:
jsonrpc: '2.0'
id: 1
method: eth_chainId
params: []
responses:
'200':
description: >-
JSON-RPC response envelope. HTTP 200 is returned for both successful
results and JSON-RPC errors; inspect the "result" and "error" fields.
content:
application/json:
schema:
$ref: '#/components/schemas/JsonRpcResponse'
examples:
userOpHash:
summary: eth_sendUserOperation result (UserOp hash)
value:
jsonrpc: '2.0'
id: 1
result: '0xdead00000000000000000000000000000000000000000000000000000000beef'
gasEstimate:
summary: eth_estimateUserOperationGas result
value:
jsonrpc: '2.0'
id: 1
result:
preVerificationGas: '0xc350'
verificationGasLimit: '0x33450'
callGasLimit: '0x88b8'
sponsorResult:
summary: zd_sponsorUserOperation result
value:
jsonrpc: '2.0'
id: 1
result:
paymaster: '0x0000000000000039cd5e8aE05257CE51C473ddd1'
paymasterData: '0x00000000...'
preVerificationGas: '0xc350'
verificationGasLimit: '0x33450'
callGasLimit: '0x88b8'
error:
summary: JSON-RPC error envelope
value:
jsonrpc: '2.0'
id: 1
error:
code: -32602
message: Invalid params
components:
schemas:
JsonRpcRequest:
type: object
required:
- jsonrpc
- method
- id
properties:
jsonrpc:
type: string
enum:
- '2.0'
id:
oneOf:
- type: integer
- type: string
method:
type: string
description: >-
The JSON-RPC method. Bundler methods: eth_sendUserOperation,
eth_estimateUserOperationGas, eth_getUserOperationByHash,
eth_getUserOperationReceipt, eth_supportedEntryPoints, eth_chainId.
Paymaster methods: zd_sponsorUserOperation, pm_sponsorUserOperation,
pm_getPaymasterStubData, pm_getPaymasterData,
zd_getERC20PaymasterAddress.
enum:
- eth_sendUserOperation
- eth_estimateUserOperationGas
- eth_getUserOperationByHash
- eth_getUserOperationReceipt
- eth_supportedEntryPoints
- eth_chainId
- zd_sponsorUserOperation
- pm_sponsorUserOperation
- pm_getPaymasterStubData
- pm_getPaymasterData
- zd_getERC20PaymasterAddress
params:
type: array
description: Positional parameters; shape depends on the method.
items: {}
JsonRpcResponse:
type: object
required:
- jsonrpc
- id
properties:
jsonrpc:
type: string
enum:
- '2.0'
id:
oneOf:
- type: integer
- type: string
result:
description: Present on success; shape depends on the method.
error:
$ref: '#/components/schemas/JsonRpcError'
JsonRpcError:
type: object
properties:
code:
type: integer
message:
type: string
data:
description: Optional error detail.
UserOperation:
type: object
description: >-
ERC-4337 UserOperation. Field set differs between EntryPoint v0.6 and
v0.7 (v0.7 splits gas/paymaster fields and uses packed accountGasLimits
on-chain); SDK-built operations carry the appropriate fields.
properties:
sender:
type: string
nonce:
type: string
factory:
type: string
factoryData:
type: string
callData:
type: string
callGasLimit:
type: string
verificationGasLimit:
type: string
preVerificationGas:
type: string
maxFeePerGas:
type: string
maxPriorityFeePerGas:
type: string
paymaster:
type: string
paymasterVerificationGasLimit:
type: string
paymasterPostOpGasLimit:
type: string
paymasterData:
type: string
signature:
type: string