Contracts & Audits - Biconomy Docs

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Contract Suite

Biconomy is versioning our smart contracts by groups. One “Suite” version contains many different versioned contracts within itself. The contracts being versioned are:

Nexus Account
Modular Execution Environment (MEE) K1 Validator (ERC-7579 Module)
Nexus Boostrap & Factory
Composability & Fusion Utils (Composable Storage, ETH Forwarder)

Versions

MEE Contracts Suite v2.3.0 (rc)

What’s New:

New fusion mode safe-sa which allows using Safe accounts as master accounts instead of EOAs

Attention! This version utilizes unaudited cotracts.

Nexus & MEE Validator

Contract Name	Contract Address
Nexus Implementation v1.3.1	`0x54F220e4f0DEAb58Be26153df5a674668B9d7Fb2`
MEE K1 Validator v1.2.0	`0x1Cdae7dcc3f32551865EfE3d77AC2b88Ee2905B4`
Nexus Bootstrap v1.3.0	`0xCa8f48912A3a33fE694c318a1d097AD394CFAB76`
Nexus Account Factory	`0x5836Bdb35913c7CBA6ef40675354445121449917`

MEE Contracts Suite v2.2.2

What’s New:

Bundles the audited ERC-8211 Smart Batching reference implementation (Ethereum Foundation & Biconomy) — the formal standardization of the composability primitives shipped in earlier versions
Expanded composability primitives and pipeline hardening
Audited by Pashov (May 2026)

Nexus & MEE

Contract Name	Contract Address
Nexus Implementation v1.3.2	`0x0000b1C0B95DA04652C1919667D1DCC14f46f62B`
MEE K1 Validator v1.1.0	`0x0000B1C0790E5a28293276C320d2B95D651dBaD6`
Nexus Bootstrap v1.3.0	`0x0000B1c0A80cb7DD166a15e7390b8A4Ced4500C6`
Nexus Account Factory	`0x0000B1c0dCFd64dfe8FeC844923B653DD0dfdB05`

ERC-8211

Contract Name	Contract Address
Composable Execution Module	`0x0000821108B5C9F3fe17E40811bE5b66DaF8f0e7`
Composable Storage	`0x00008211dea1Aca67ac55fc44AE3bF88CF41281d`

Utility

Contract Name	Contract Address
ETH Forwarder	`0x0000B1C0Fc7015Effa85892426FAEd8211B2d62E`
Node Paymaster Factory	`0x0000B1C059753ae6d1C135605377cE6487385960`

MEE Contracts Suite v2.2.1 (latest)

What’s New:

New composability version - enables native token runtime injection
Sign EIP-712 Data Struct instead of blind Stx hash for the smart-account mode
New ERC-7702 Nexus accounts can be initialized via relayers
Gas optimizations

Nexus & MEE Validator

Contract Name	Contract Address
Nexus Implementation v1.3.1	`0x0000000020fe2F30453074aD916eDeB653eC7E9D`
MEE K1 Validator v1.1.0	`0x0000000002d3cC5642A748B6783F32C032616E03`
Nexus Bootstrap v1.3.0	`0x000000007BfEdA33ac982cb38eAaEf5D7bCC954c`
Nexus Account Factory	`0x000000002c9A405a196f2dc766F2476B731693c3`

Composability & Utility

Contract Name	Contract Address
Composable Execution Module	`0x00000000f61636C0CA71d21a004318502283aB2d`
Composable Storage	`0x0000000078994c6ef6A4596BE53A728b255352c2`
ETH Forwarder	`0x000000C48Cdf2b46bEc062483dBD27046dfE3b8d`

MEE Contracts Suite v2.1.0 (Current Default)

What’s New: K1 MEE module introduced - enables ERC-7702-delegated EOAs to own Nexus accounts

Nexus & MEE Validator

Contract Name	Contract Address
Nexus Implementation v1.2.0	`0x00000000383e8cBe298514674Ea60Ee1d1de50ac`
MEE K1 Validator v1.0.3	`0x0000000031ef4155C978d48a8A7d4EDba03b04fE`
Nexus Bootstrap v1.2.1	`0x0000003eDf18913c01cBc482C978bBD3D6E8ffA3`
Nexus Account Factory	`0x0000006648ED9B2B842552BE63Af870bC74af837`

Composability & Utility

Contract Name	Contract Address
Composable Storage	`0x0000000671eb337E12fe5dB0e788F32e1D71B183`
ETH Forwarder	`0x000000Afe527A978Ecb761008Af475cfF04132a1`

MEE Contracts Suite v2.0.0

Major release with Nexus 1.2.0, ERC-7702 support, and native composability

Nexus & MEE

Contract Name	Contract Address
Nexus Implementation v1.2.0	`0x000000004F43C49e93C970E84001853a70923B03`
MEE K1 Validator v1.0.1	`0x00000000d12897DDAdC2044614A9677B191A2d95`
Nexus Bootstrap v1.2.1	`0x00000000D3254452a909E4eeD47455Af7E27C289`
Nexus Account Factory	`0x000000001D1D5004a02bAfAb9de2D6CE5b7B13de`
MEE EntryPoint & Paymaster	`0xE854C84cD68fC434cB3B0042c29235D452cAD977`

Composability & Utility

Contract Name	Contract Address
Composable Storage	`0x0000000671eb337E12fe5dB0e788F32e1D71B183`
ETH Forwarder	`0x000000Afe527A978Ecb761008Af475cfF04132a1`

MEE Contracts Suite v1.1.0 Pre-cancun

Compiled for EVM Paris (No PUSH0, no MCOPY, no TSTORE)

Nexus & MEE

Contract Name	Contract Address
Nexus Implementation v1.0.2	`0x000000001964d23C59962Fc7A912872EE8fB3b6A`
MEE K1 Validator v1.0.3	`0x00000000E894100bEcFc7c934Ab7aC8FBA08A44c`
Nexus Bootstrap v1.0.0	`0x000000c4781Be3349F81d341027fd7A4EdFa4Dd2`
Nexus Account Factory	`0x0000000C8B6b3329cEa5d15C9d8C15F1f254ec3C`

Composability & Utility

Contract Name	Contract Address
Composability Module	`0x000000Fc19Cf049b445dd5CC0D590f6f93075f42`
Composable Storage	`0x000000d2520640d0993B58112b929e71C9747300`
ETH Forwarder	`0x000000001f1c68bD5bF69aa1cCc1d429700D41Da`

MEE Contracts Suite v1.0.1

Added Nexus Account Factory at 0x000000903887EA36EBe051038287f49fD4A07733

MEE Contracts Suite v1.0.0

Initial release - Requires manual installation of MEE K1 validator and Composability module

GitHub Release →

Nexus & MEE

Contract Name	Contract Address
Nexus Implementation v1.0.2	`0x000000aC74357BFEa72BBD0781833631F732cf19`
MEE K1 Validator v1.0.1	`0x00000000d12897DDAdC2044614A9677B191A2d95`
Nexus Bootstrap v1.0.0	`0x879fa30248eeb693dcCE3eA94a743622170a3658`
Nexus Account Factory	`0x000000c3A93d2c5E02Cb053AC675665b1c4217F9`
MEE EntryPoint & Paymaster	`0xE854C84cD68fC434cB3B0042c29235D452cAD977`

Composability & Utility

Contract Name	Contract Address
Composability Module	`0x00000004430bB055dB66eBef6Fe5Ee1DA9668B10`
Composable Storage	`0x0000000671eb337E12fe5dB0e788F32e1D71B183`
ETH Forwarder	`0x000000Afe527A978Ecb761008Af475cfF04132a1`

Nexus Audits

Cyfrin

Competition Audit

Spearbit

Zenith

Full Review

Pashov

2025 Review

MEE Stack Audits

MEE Stack

Audited by Zenith

MEE EntryPoint
Node Paymaster
MEEK1 Validator

Composability Stack

Multiple Auditors

Pashov Report (2026-05, ERC-8211 / v2.2.2) — covers the audited submodule pinned in v2.2.2 (signed constraints, IN_SIGNED, OR composition, SKIP, pipeline hardening)
Zenith Report (2025-03)
Pashov Report (2025-03)

Legacy Contracts

These contracts are deprecated. Use the latest version for new deployments.

Nexus v1.0.1 Production

Contract Name	Contract Address
Nexus Implementation	`0x000000008761E87F023f65c49DC9cb1C7EdFEaaf`
K1 Validator	`0x0000002D6DB27c52E3C11c1Cf24072004AC75cBa`
K1 Validator Factory	`0x00000024115AA990F0bAE0B6b0D5B8F68b684cd6`
Account Factory	`0x000000226cada0d8b36034F5D5c06855F59F6F3A`
Bootstrap	`0x000000F5b753Fdd20C5CA2D7c1210b3Ab1EA5903`
EntryPoint V7	`0x0000000071727de22e5e9d8baf0edac6f37da032`

Paymaster Contracts

Base & Optimism

Contract Name	Contract Address
Sponsorship Paymaster	`0x0000006087310897e0BFfcb3f0Ed3704f7146852`
Token Paymaster	`0x00000000301515A5410e0d768aF4f53c416edf19`

Other Chains

Contract Name	Contract Address
Sponsorship Paymaster	`0x00000072a5F551D6E80b2f6ad4fB256A27841Bbc`
Token Paymaster	`0x00000000301515A5410e0d768aF4f53c416edf19`

​Contract Suite

​Versions

​Nexus & MEE Validator

​Nexus & MEE

​ERC-8211

​Utility

​Nexus & MEE Validator

​Composability & Utility

​Nexus & MEE Validator

​Composability & Utility

​Nexus & MEE

​Composability & Utility

​Nexus & MEE

​Composability & Utility

​Nexus & MEE

​Composability & Utility

​Nexus Audits

Cyfrin

Spearbit

Zenith

Pashov

​MEE Stack Audits

MEE Stack

Composability Stack

​Legacy Contracts

​Base & Optimism

​Other Chains

Contract Suite

Versions

Nexus & MEE Validator

Nexus & MEE

ERC-8211

Utility

Nexus & MEE Validator

Composability & Utility

Nexus & MEE Validator

Composability & Utility

Nexus & MEE

Composability & Utility

Nexus & MEE

Composability & Utility

Nexus & MEE

Composability & Utility

Nexus Audits

MEE Stack Audits

Legacy Contracts

Base & Optimism

Other Chains