Summary

Here’s a solid, step-by-step guide for getting your production-ready web3 contracts up and running in 2025. We’re diving into everything--from the specifics of your project and the architecture (like AA through ERC-4337 and EIP-7702) to which testnets and forks you should be using. We’ll also cover your audit game plan (think static, dynamic, and formal), verification strategies (using Sourcify or Etherscan V2), and how to toughen up your mainnet launch to sync up with Pectra on May 7, 2025, and Fusaka on December 3, 2025. Check it out here: (blog.ethereum.org)

web3 contract development service: From Specs to Audits to Mainnet Launch

Decision-makers don’t need another basic overview--you’re looking for a reliable roadmap that takes you from an approved spec all the way to a secure mainnet launch. And we get that the 2025 protocol landscape (think Pectra, Fusaka, 7702, and PeerDAS) needs to be integrated at every stage. This is exactly how 7Block Labs manages full-cycle web3 projects that actually deliver results.

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What changed in 2025 (and why it affects your build plan)

• So, Ethereum’s Pectra hard fork went live on May 7, 2025. This update introduced EIP‑7702, which gives us opt-in “programmable EOAs,” bumped up validator limits with EIP‑7251, and doubled the blob capacity for rollups thanks to EIP‑7691. If you’re working on wallet UX or thinking about layer‑2 cost models, your plans just got a bit of a reset. Check out the details here.
• Then there’s Fusaka, which lit up on December 3, 2025, right at 21:49:11 UTC (that’s slot 13,164,544 for the folks keeping score). It’s packed with features like PeerDAS (EIP‑7594) to help with cheaper L2 data, a new default L1 gas limit of 60M (EIP‑7935), a fresh CLZ opcode (EIP‑7939), and even a secp256r1 (P‑256) signature precompile (EIP‑7951). Mark Dec 9, 2025, and Jan 7, 2026, on your calendar for some noticeable bumps in BPO blob-throughput. You might want to rethink your fee, operations, and cryptography strategies to stay ahead. More info can be found here.
• The testnet landscape is changing a bit: Holesky is set to sunset in 2025, and now Hoodi has taken the spotlight as the validator/staking testnet. Sepolia will continue to be your go-to for app/dev testing. If your CI/CD or test playbooks are still counting on Goerli/Holesky, it’s time to give them an update. Catch the full scoop here.
• On the Solidity front, things got a nice boost: version 0.8.30 aligned the defaults with Pectra, and then 0.8.31 (released on Dec 3, 2025) brought in support for Fusaka along with improved storage-layout tooling. This is super important for those working on upgradeable systems and figuring out 7702 storage placement. Dive into the details here.

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The 7Block Labs delivery track

We roll things out in four gated phases. Each gate produces artifacts that your legal, risk, and engineering teams can review and approve.

1) Product spec, threat model, and chain selection

Outputs: You'll get a PRD and a spec that includes measurable acceptance criteria, an adversarial model, a data/fee model, plus a plan for the chain/testnet.

What We Lock Down:

When we’re talking about lockdowns, there are a few key areas we usually focus on. Here’s a quick rundown:

• Public Spaces: This includes parks, beaches, and any other gathering spots.
• Schools: Most educational institutions close their doors to keep students and staff safe.
• Businesses: Non-essential shops, restaurants, and entertainment venues often shut down during lockdowns.
• Transportation: Public transport may be limited, and travel bans might be put in place between regions or countries.
• Events: All sorts of gatherings, from concerts to sports events, generally get called off to prevent large crowds.

Each lockdown situation can vary quite a bit depending on the current conditions and the specific regulations in place. You can find more detailed information on local lockdown measures through official government websites or health organizations.

• Target forks and EIPs: Let's make sure we're on the same page with the Pectra+Fusaka assumptions. We're looking at a per-transaction gas cap of about 16.78M (thanks to EIP-7825), and the default L1 gas limit is set at 60M via EIP-7935. Don’t forget, PeerDAS is live! If your multicalls or gas-heavy admin operations exceed these limits, you’ll need to break them up. Check out more details on the Ethereum blog.
• Account model: Decide whether you want to go with ERC-4337 smart accounts, EIP-7702 “smart EOAs,” or a mix of both. Using 7702 gives you seamless address continuity, while 4337 is great for mature infrastructure like bundlers and paymasters. We’ve documented everything about paymaster policy, rate limits, and signer UX--by the way, passkeys are now first-class citizens thanks to P-256 on L1. Dive into the specifics on ERC4337 docs.
• Upgrade strategy: You’ve got options here: choose between UUPS/proxy, modular diamonds (ERC-2535), or immutable setups. If you do go for something upgradeable, we recommend keeping your storage organized with storage gaps and/or ERC-7201 namespaced storage. Get the full scoop on this at OpenZeppelin docs.
• Testnets and CI: For app flows, we’re using Sepolia; and for anything validator-adjacent (like staking or blob producing), Hoodi is the go-to. We’ll outline which flows are running where and why, so everything stays clear. Check out more details on the Ethereum blog.

2) Architecture and PoC

Outputs: reference architecture, prototype contracts, interface documentation, and a clear security budget that you can actually measure.

Concrete 2025 Choices We Recommend:

Here are some solid picks for 2025 that we think you’ll love:

• Programmable EOAs (EIP‑7702) for smoother migrations: You can now hang onto your EOA address while temporarily handing over control to some audited logic. The tools have really come a long way: MetaMask’s Smart Accounts Kit now shows off 7702 flows, and Foundry’s forge‑std has rolled out 7702 cheat codes for testing authorizations right from your local setup. Check it out here: (docs.metamask.io)
• Passkey‑native auth without bridges: With EIP‑7951, you can verify P‑256 signatures directly on L1. This makes life a lot easier for enterprise SSO and mobile biometric setups. We’re throwing in some guardrails for situations where non‑malleability or hardware policies come into play. More details here: (blog.ethereum.org)
• Data availability economics: PeerDAS (EIP‑7594) is shaking things up by changing blob proof formats and data availability costs. We’re on it, validating your rollup/L2 interactions against the new “cell proofs” and the BPO schedule, while also sizing infrastructure like indexers and explorers accordingly. Dive deeper here: (blog.ethereum.org)

Example: 7702 Authorization and Execution with MetaMask Smart Accounts Kit

When working with the MetaMask Smart Accounts Kit, you might come across the 7702 authorization and execution process. Let's break it down step-by-step, so you can easily understand how to get things rolling.

What You Need

Before diving in, make sure you have:

• A MetaMask account set up and ready to go.
• The Smart Accounts Kit installed. If you're not sure how to get it, check out the MetaMask documentation.

Step 1: Setting Up Your Environment

1. Install the Smart Accounts Kit if you haven't already.
2. Open your MetaMask and log in to your account.

Step 2: Authorizing with 7702

To authorize using 7702, you’ll need to call the relevant function in your code. Here’s a quick snippet to get you started:

const result = await smartAccount.authorize({
  type: '7702',
  // your parameters go here
});

Step 3: Executing the Transaction

After you’ve got the authorization down, it’s time to execute the transaction. Here’s how:

const executionResult = await smartAccount.execute({
  // insert your execution parameters
});

Step 4: Checking the Results

To see if everything went smoothly, you can check the results with:

if (executionResult.success) {
  console.log('Transaction successful:', executionResult);
} else {
  console.error('Transaction failed:', executionResult.error);
}

Important Notes

• Make sure you have enough gas for the transaction to go through, or you might run into some hiccups.
• Always double-check your parameters before executing, to avoid any unnecessary errors.

Now that you've got the basics down, feel free to tweak this process to fit your needs. Happy coding!

import { createWalletClient, http } from "viem";
import { sepolia } from "viem/chains";
import { privateKeyToAccount } from "viem/accounts";
import {
  getDeleGatorEnvironment,
  toMetaMaskSmartAccount,
  Implementation,
} from "@metamask/delegation-toolkit";

const account = privateKeyToAccount(process.env.PK as `0x${string}`);
const wallet = createWalletClient({ account, chain: sepolia, transport: http() });

const env = getDeleGatorEnvironment(sepolia.id);
const delegatorImpl = env.implementations.EIP7702StatelessDeleGatorImpl;

// 1) authorize contract code to your EOA (7702)
const mmSmartAccount = await toMetaMaskSmartAccount({
  walletClient: wallet,
  implementation: Implementation.EIP7702StatelessDeleGator,
  delegatorImplAddress: delegatorImpl,
});

// 2) batch safe operations while EOA delegates
await mmSmartAccount.sendTransaction({
  to: targetAddress,
  data: batchedCalldata,
});

With this pattern, you get the benefits of batching and sponsored gas, all while users can stick with their familiar address. Check out more details here!

3) Dev, testing, and proofs

Outputs: code in a solid monorepo, coverage and invariant dashboards, and formal specs wherever it makes sense.

Toolchain We Standardize (2025-Ready):

• We’re rolling with Solidity 0.8.31 set to the right EVM version (Pectra/Prague or Fusaka/Osaka) and using the via-IR pipeline to get some solid analysis artifacts. For those experimental EOF paths, we stick to exact versions and avoid inline assembly that could mess things up under EOF. Check out more at (soliditylang.org).
• For our testing suite, we’re all about Foundry for unit, integration, fuzz, and invariant tests. The new forge-std helpers (like 7702, EIP-712 helpers, and deeper traces) really help us test account abstraction and complex signatures without needing a whole setup. Here are some sample flags we’re using in CI:
  • forge test -vvv --fork-url $RPC --isolate --fail-fast
  • forge coverage --report lcov --ffi
  • forge test --fuzz-runs 20000 --match-path test/invariants/*.t.sol

We also set up Anvil trace logging and depth-limited tree traces to help with exploit triage. Check it out on GitHub!

• Static and symbolic analysis:
  • Check out Slither for some speedy detectors and architectural printers that are connected to PR gates. (github.com)
  • Use Mythril to dive into targeted symbolic paths, especially in those high-risk modules. (github.com)
• Property-based fuzzing and invariants:
  • We're using Echidna 2.2+ with coverage guidance. We like to run long-term campaigns and keep our corpus artifacts. Check out this example config:

testMode: assertion
coverage: true
seqLen: 40
testLimit: 500000
maxTime: 14400     # 4 hours per target
multi-abi: true
allContracts: true

(GitHub Releases)

• Where formal verification really shines:
  • Check out Certora Prover using CVL specs for those critical invariants like collateralization, mint/burn conservation, and role-gated flows. We keep our rules versioned, utilize parametric rules, and run the prover in CI whenever we tweak modules. You can find more details here.
• Keeping storage safe for upgradeables:
  • Make sure to enforce storage gap reductions and/or use ERC‑7201 namespaces. Also, run OZ Upgrades validations in CI to prevent any dodgy upgrades. (docs.openzeppelin.com)

4) Audit, verification, and launch readiness

Outputs: an auditor-ready repo, a signed audit checklist, verified artifact links, and a handy incident response runbook.

What We Do Before You Hit “Deploy”:

Before you go ahead and click that “deploy” button, here’s a quick rundown of all the essential steps we take to ensure everything goes smoothly:

1. Code Review
   Our team thoroughly reviews your code to catch any issues before it goes live. We want to make sure it's clean, efficient, and ready to rock.
2. Automated Testing
   We run a series of automated tests to check for bugs and potential roadblocks. This helps us confirm that everything is functioning as it should.
3. Manual Testing
   Once the automated tests are done, we do some hands-on testing. This way, we can see how it works in real-time and catch anything that might have slipped through the cracks.
4. Performance Checks
   We take a close look at the performance metrics to ensure the application runs smoothly under different loads. After all, we want your users to have a great experience!
5. Backup
   Before anything goes live, we make a backup of your existing application. Just in case something unexpected happens, we can easily roll back to the previous version.
6. Documentation Review
   We check all your documentation to make sure it’s up to date and accurately reflects the latest changes. Clear documentation means easier maintenance down the line.
7. Deployment Plan
   Finally, we create a deployment plan outlining the steps and timeline for the rollout. This keeps everyone on the same page and makes the process as smooth as possible.

Once all that’s done and dusted, you can confidently press “deploy” knowing we’ve got your back!

• Attack-Surface Freeze and Audit Package: We’ve got a detailed threat model, a comprehensive dependency matrix, 3P oracles and price feeds, plus we take a hard look at fork-specific risks (think 7702 validation rules and P-256 signature handling). You can expect coverage/invariant reports and Certora proofs included in the package.
• External Audit Coordination: We kick things off by sharing our internal findings upfront, so when it's time for the external audit, you’re getting additional confidence rather than just fixes from the first pass.
• Verification and Reproducibility:
  • We use Sourcify for “exact_match” verification that relies on compiler metadata for reproducible builds. You can also programmatically expose ABIs and metadata through the Sourcify API v2. Check out the details in the Sourcify docs.
  • We’re migrating to Etherscan API V2, which means multichain verification is a go! We’ve also set up proxy verification endpoints for UUPS and transparent proxies. Just a heads up: V1 deprecation is coming up--switch by May 31, 2025, and full V1 shutdown will happen on August 15, 2025. More info can be found on the Etherscan site.
• Operational drills: pause/guardian flows; break-glass signer runbooks; event schema and analytics; production alerting for any unusual state transitions.

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A. Foundry config for Fusaka‑ready builds (Solidity 0.8.31)

# foundry.toml
[profile.default]
solc_version = "0.8.31"
evm_version  = "osaka"      # Fusaka execution layer
optimizer = true
optimizer_runs = 200
via_ir = true
ffi = true

[fuzz]
runs = 20000
seed = "auto"

[invariant]
runs = 512
depth = 128
fail_on_revert = false

Solidity 0.8.31 brings in support for Fusaka and also expands the storage layout specifiers. This is pretty handy for working with namespaced storage in AA/7702 code paths. Check it out here: (soliditylang.org).

B. Invariant test skeleton for asset conservation

contract Invariants is Test {
  DeployedSystem sys;

  function setUp() external {
    sys = new DeployedSystem();
  }

  function invariant_totalSupplyConserved() external {
    uint256 minted = sys.token().totalMinted();
    uint256 burned = sys.token().totalBurned();
    uint256 supply = sys.token().totalSupply();
    assertEq(minted - burned, supply, "supply conservation");
  }
}

C. Slither and Echidna in CI

# Static analysis
slither . --config-file slither.config.json

# Property-based fuzzing
docker run --rm -v "$PWD:/src" trailofbits/echidna:2.2.7 \
  echidna-test /src/out/Your.t.sol/Your.json --config /src/echidna.yml

Slither delivers quick structural insights, while Echidna 2.2.7 brings improved coverage and ARM builds for a broader selection of CI runners. Check it out here: (github.com)

D. Sourcify verification via metadata JSON

# Assuming build-info JSON or per-contract metadata.json available
curl -X POST https://sourcify.dev/server/v2/verify \
  -F "address=0xYourContract" \
  -F "chainId=1" \
  -F "files=@./artifacts/build-info/123.json"

Sourcify now takes advantage of Solidity’s compiler metadata for byte-exact verification and has rolled out v2 lookup endpoints for checking things programmatically. You can dive into the details here.

E. Etherscan V2 multichain contract verification (proxy included)

# Source-code verification (V2)
curl -X POST "https://api.etherscan.io/api" \
  -d 'chainId=1&module=contract&action=verifysourcecode&...&apikey=$KEY'

# Proxy verification (enforce expected implementation)
curl -X POST "https://api.etherscan.io/api" \
  -d 'chainId=1&module=contract&action=verifyproxycontract&address=0xProxy&expectedimplementation=0xImpl&apikey=$KEY'

Make sure to switch to the Etherscan API V2 before it gets deprecated! Using the proxy endpoints will help maintain a smooth and consistent user experience for the “Read/Write as Proxy” feature. Check out the details here.

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2025‑aware best practices we enforce

• Make sure no single transaction goes over about 16.78M gas (thanks to EIP‑7825). It’s a good idea to break up admin batches and plan your upgrade steps to stay within this limit. (blog.ethereum.org)
• For upgradeable contracts, it's better to stick with ERC‑7201 namespaced storage (or leave some gaps for conservative storage). Don’t forget to validate everything with OZ Upgrades for every PR. (eips.ethereum.org)
• If you’re going with EIP‑7702, keep those delegator contracts simple and stateless, and set a time limit for authorizations. You can test it out using the forge‑std 7702 helpers alongside MM Smart Accounts Kit flows. (github.com)
• When using passkeys (P‑256), be sure to have clear malleability policies in the right places. The precompile makes verification easier, but your app's user experience and security policies are still super important. (blog.ethereum.org)
• If you’re relying on blobs (like L2 rollups), make sure to update your tools for PeerDAS proof formats and keep an eye on BPO throughput changes starting Dec 9, 2025. (blog.ethereum.org)
• Consider phasing out Holesky from your CI; it’s better to use Sepolia for app flows and Hoodi when you’re testing validator lifecycles. (blog.ethereum.org)

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Risk and audit reality check

Crypto losses took some wild swings in 2025, especially in Q1, which saw a lot of chaos thanks to incidents in the CeFi space. Despite the ups and downs, DeFi continues to be a favorite target for attackers. Our audit plan is built with this in mind, assuming that the adversaries we face are not only motivated but also well-resourced. We’re layering our testing--using static, fuzz, symbolic, and formal methods--before we even bring in the external auditors. (theblock.co)

What Our Audit Gate Covers:

• Documentation Review: We take a close look at all your important documents to make sure everything's in order.
• System Checks: Our team will run through your systems to ensure they’re functioning effectively and securely.
• Compliance Assessment: We’ll assess how well you’re complying with relevant regulations and industry standards.
• Risk Analysis: Identifying any potential risks is key, so we’ll analyze and highlight any areas of concern.
• Recommendations: We don’t just stop at findings; we’ll provide actionable advice to help you improve.

Got questions? Reach out anytime!

• Coverage and invariant thresholds (automatic failures if we fall short of targets).
• Handy manual review checklists for potential pitfalls like proxies/initializers, cross-chain bridges/oracles, reentrancy/approval races, rounding/overflow issues in fee calculations, and role/RBAC inconsistencies.
• Formal specifications to ensure monetary invariants and permission boundaries (Certora rules stored right alongside the code). (docs.certora.com)

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Launch and post‑launch

• Make sure to verify everything (use Sourcify for exact matches and check out Etherscan V2). Publishing your metadata and NatSpec can really help reduce support requests and make life easier for integrators down the line. Check out the details here: (docs.sourcify.dev).
• Implement feature flags and modules that can be paused when necessary. It's also a good idea to do some practice runs for emergency cutovers and communication before hitting the mainnet.
• Keep an eye on the on-chain activities: set up alerts for any unexpected changes in storage, gaps in events, and any discrepancies in price or oracle data.

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What you get with 7Block Labs

• A signed, testable spec that matches up with the Pectra/Fusaka realities.
• A repository filled with tests (including unit, integration, fuzz, and invariants), along with Slither/Mythril reports and optional Certora proofs.
• An audit-ready package and a well-coordinated external review process.
• Verified artifacts (thanks to Sourcify + Etherscan V2), a handy incident playbook, and a smooth launch plan.

If you're diving into the world of wallets, fintech, DeFi, RWAs, or even enterprise chain extensions, we've got your back. We can help you figure out the best Account Abstraction (AA) approach for your needs--whether it's 4337, 7702, or a combo of both. Plus, we’ll design for PeerDAS blob economics and ensure everything ships smoothly, with no unexpected hiccups.

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References and change‑sensitive details we track for you

• Pectra and EIP‑7702 Activation and Scope: You can check out the details on the Ethereum blog for everything you need to know about the Pectra activation and EIP‑7702's scope.
• Fusaka Mainnet Activation: The lowdown on the Fusaka mainnet activation, including the BPO schedule and the EIPs that are part of it (think PeerDAS, CLZ, secp256r1, and gas-limit), is available here.
• Testnet Transitions: If you want to stay updated on the testnet transitions from Holesky to Hoodi, and how to use Sepolia for your app development, check out this post.
• Solidity Releases: Exciting changes are happening with the Solidity 0.8.30/0.8.31 releases (Prague/Osaka), including updates to storage layout. You can find all the details on the Solidity blog.
• Etherscan API V2 Migration: Don't forget the deadlines for migrating to Etherscan API V2 and info on proxy verification endpoints. Get the scoop here.
• PeerDAS Proof-Format Updates: Curious about the latest updates on PeerDAS proof formats and the blob throughput scaling plan? Dive into the details on the Ethereum blog.

Ready to dive into your build? We’ll help transform your specifications into a mainnet launch plan that aligns with the current state of Ethereum today--not just where it was during the last cycle.