A guide to hiring Ethereum developers
Ethereum is a public network where programs, called smart contracts, hold rules and records that anyone can check. Once a contract is live it is hard to change, so the people who write it carry real responsibility. This guide explains what Ethereum developers do, how the role differs from nearby roles and how to set up the work so it goes smoothly. It suits a founder with a first token idea as well as a company that wants to add Ethereum features to an existing product.
What Ethereum developers work on
Most Ethereum work falls into four groups. Contracts are the on-chain programs, written mostly in Solidity. Tokens are contracts that follow shared standards so wallets and apps can handle them. Apps are the websites and mobile screens that let people use the contracts through a wallet. Data work covers reading events from the chain and storing them so your app can answer questions quickly. A small project may need one person for all four, while a bigger one splits them.
How this role differs from nearby roles
An Ethereum developer works on one family of networks in depth. Our blockchain developer page covers wider work, such as other chains, wallets, exchanges and full products. Our smart contract developer page is about contract code on any network. Choose this page when you already know that Ethereum or an Ethereum layer 2 is your home. If your product also handles payments, bank links or ledgers, our fintech developer page may help, and a Python team can support data and back-end tasks.
Mainnet and layer 2
- Mainnet is the main Ethereum network. It has the widest reach, and each transaction costs more.
- Layer 2 networks such as Arbitrum, Optimism and Base batch work and settle on Ethereum, which usually lowers cost for users.
- Other EVM chains, such as Polygon, run the same contract language but have their own rules and risks.
- Test networks let your developer try everything with play money before a real launch.
Say early which network you plan to use. It changes the tools, the testing and the way users pay fees.
What to decide before you hire
- What the contracts must do, and what can stay off-chain in an ordinary server.
- Which network you will launch on, and which test network you will use first.
- Whether the contracts are fixed or upgradeable, and who holds the admin keys.
- Whether you need a front end, an indexer or an API on top of the contracts.
- When an outside firm will review the code, and how long you will leave for fixes.
Reading an Ethereum developer’s profile
Public code helps. Ask for contracts the person wrote, with the address on a block explorer if they are live, and read the tests. Look at how the repository is organised and whether the commit notes explain the changes. Be careful with profiles that list many projects but cannot say which part was theirs. Ask what went wrong on a real project and what they changed afterwards. A developer who can explain a failure honestly is easier to trust than one who has none to share.
Interview questions to try
- Explain how a user pays for a transaction, and how you would lower that cost in a contract you wrote.
- How do you test a contract that depends on another protocol’s prices or balances?
- When would you choose an upgradeable contract, and what risks does it add?
- Walk us through a bug you found late. How did you find it and what did you change?
- How do you prepare code for an outside review, and what do you do with the findings?
Listen for plain answers with examples. Doubt anyone who says a contract cannot have bugs.
Run a small paid task
Give each finalist a short brief that matches your product. Good examples are a small escrow contract with tests, a token with a simple vesting rule, or a review of a short contract that contains a planted mistake. Pay for the time. Compare how clear the code is, how well the tests cover the edge cases and how the person handles questions about your users.
Match experience to the stage
At the prototype stage you need someone who can build on a test network quickly and keep the design simple. Before launch you need a developer who is strong at testing, writes careful notes and works well with outside reviewers. After launch you need steady maintenance, monitoring and clear plans for what happens when something goes wrong. Job titles differ between teams, so ask what each person owned rather than relying on the title.
Give them tools and a rhythm
Give your developer access to the repository, the test networks and the build pipeline, and no more than the job needs. Keys that control funds should stay with your company, ideally behind a multisig wallet that needs more than one approver. In the first month, talk at least once a week and review each change together. After that, a short note each week and a code review before every deploy will do.
Working with auditors and your own team
An outside review is a separate step and does not replace good habits inside the team. Book it early, because good reviewers have waiting lists. Give them a frozen version of the code, a plain description of what it should do and the test results. Ask your developer to be on hand to answer questions and fix findings. Keep your product, legal and support teams in the loop so that nobody is surprised by how the contracts behave.
Mistakes to avoid
- Putting everything on-chain when an ordinary database would do the job.
- Launching without tests on a network that matches the real one.
- Giving one person sole control of the keys that move funds.
- Copying code you do not understand from a forum or a repository.
- Letting a contractor own your repository, keys or cloud accounts.
Need a wider team or other networks as well? Read about how to hire a blockchain developer or a smart contract developer, and see how hiring works on our pages.