12Service
Smart contracts & Web3
Solidity contracts and the APIs around them, from someone who led blockchain teams from 2017 to 2019.
The short answer
Updated
Smart contract development is writing the code that runs on a blockchain, usually Solidity on Ethereum or another EVM chain, plus the services that let a normal app use it. I keep the on-chain part small and fully tested. Most projects take 4 to 6 weeks, plus the audit and cost $5k to $20k.
- Typical budget
- $5k to $20k
- Timeline
- 4 to 6 weeks, plus the audit
- How it's quoted
- An independent audit is quoted separately by the audit firm.
Contracts that hold money should be boring. I write boring contracts.
Between 2017 and 2019 I led blockchain development on four products, on Ethereum and QTUM. Most of it is under NDA. The lesson from all of it: keep on-chain logic small and put everything else in normal, testable services.
Today I mostly help teams that need a contract written, reviewed or connected to a real product. That includes AI products that settle on chain.
A good fit if
- You need a token, registry or escrow contract written and tested
- Your app needs to read and write to a chain without exposing users to the mess
- You want a second pair of eyes on a contract before an audit
- You're mixing AI agents with on-chain actions
What you get
- 01
Tested contracts
Solidity with full test coverage on Hardhat, deployed to testnet before anything touches mainnet.
- 02
APIs in front of the chain
Node.js services that index events and wrap transactions, so your app talks to a normal API.
- 03
Audit-ready code
Clear docs and threat notes, so an external audit is faster and cheaper.
- 04
Deployment and handover
Scripts, addresses, verified source and a runbook for upgrades.
How a project runs
Week 1
Design
What has to be on chain and what doesn't. Usually less than you think.
Weeks 2 to 4
Build and test
Contracts and tests, then the API layer that wraps them.
Week 5
Testnet
Run it as if it were live, with your app connected.
After audit
Mainnet
Deployment, verification and monitoring.
- Solidity
- Ethereum
- EVM chains
- Hardhat
- Truffle
- Web3.js
- Node.js
- QTUM
Related work
All of it is under NDA. The private ledger lists it by role, stack and size. See the ledger
Questions people ask
Do you do security audits?
I review contracts and write them to be audit-ready, but for anything holding real value I'll always recommend an independent audit firm as well.
Which chains?
Ethereum and EVM-compatible chains. I've also shipped on QTUM.
Can you work with our existing contracts?
Yes. I start by reading them and the deployment history, then we decide whether to extend, migrate or leave them alone.
Why does an AI engineer do Web3?
Because I did it first. Blockchain taught me to design systems where mistakes are expensive and permanent, which turns out to be good training for putting AI in production.
How much does a smart contract cost?
Usually $5k to $20k for the contracts, tests and the API around them. A single token or registry contract is the low end. An independent audit is quoted separately by the audit firm.
How long does it take?
4 to 6 weeks, plus the audit. The testnet week is not optional.
Related services
Contact
Tell me what you're trying to fix.
I read every message myself and usually reply the same day. A rough idea is enough to start.
Or send a short briefHours
Your hours work for me.
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Me
I keep flexible hours and move my day to overlap with yours, whether that's a morning standup in New York or a late release in Sydney.