Blockchain and Web3 development
Gjethe builds smart contracts, decentralised applications, tokens, NFT memberships and wallet-based logins on Ethereum, EVM networks such as Base, Arbitrum and Polygon, and Solana. We build on audited OpenZeppelin libraries, test thoroughly and recommend an independent security audit before any contract holds significant value.
- Free first consultation
- Written quote for your project
- Flexible payment milestones
At a glance
- Networks
- Ethereum, Base, Arbitrum, Polygon, Solana
- Contracts
- Solidity, Rust
- Security
- OpenZeppelin, full test suites
- Audits
- Independent audit recommended
Definition
What is blockchain & Web3?
Blockchain development is building software that runs on, or interacts with, a blockchain: smart contracts that execute on-chain, and the web or mobile applications (dApps) that let people use them through a crypto wallet.
Blockchain is useful when you need shared, tamper-evident records, digital ownership that users control, or programmable payments without a central intermediary. It's unnecessary, and expensive, when a normal database would do. We'll tell you which applies. When blockchain is the right tool, we treat contract code with the caution it deserves: it handles value and is hard to change once deployed.
Who is it for?
Web3 startups
You're building a product where on-chain ownership or payments are central to the value.
Brands and communities
Token-gated memberships, digital collectibles or loyalty programmes tied to wallets.
Businesses adding blockchain features
Wallet login, on-chain receipts or token payments added to an existing product.
Projects needing a second pair of eyes
Existing contracts that need tests, refactoring or preparation for an external audit.
What's included, and what you keep
What's included
- Feasibility check: does this need a blockchain?
- Network and architecture recommendation
- Smart contract development in Solidity or Rust
- Token contracts: ERC-20, ERC-721, ERC-1155, SPL
- Comprehensive automated tests and fuzzing
- Testnet deployment and verification
- dApp front end with wallet connection
- Wallet login and token gating
- Indexing for fast on-chain data in the UI
- Admin roles and upgrade strategy
- Audit preparation and remediation support
- Mainnet deployment
What you receive
Handed over at the end. Yours to keep.
- Verified contracts on the chosen network
- Contract source code and test suite
- dApp front end
- Deployment scripts and addresses
- Technical documentation for auditors and integrators
Which network should you build on?
| Network | Strengths | Consider |
|---|---|---|
| Ethereum mainnet | Maximum security and ecosystem | Higher transaction fees |
| EVM layer-2s (Base, Arbitrum, Optimism) | Ethereum compatibility with low fees | Bridging and L2-specific details |
| Polygon | Low fees, broad tooling | Different security model from L2 rollups |
| Solana | High throughput, low fees, consumer apps | Rust and a different programming model |
How we approach smart contract security
- Build on audited OpenZeppelin contracts instead of reinventing standards
- Keep contracts small and logic simple
- Unit tests, fuzz tests and invariant tests with Foundry
- Role-based access control and minimal admin powers
- Explicit upgrade or immutability strategy
- Testnet deployment and review before mainnet
- Independent audit for anything holding significant value
Do you actually need a blockchain?
A blockchain makes sense when several parties who don't fully trust each other need a shared record, when users should truly own and transfer digital assets, or when payments must be programmable without an intermediary.
If one company controls the data and users trust it, a normal database is faster, cheaper and easier to change. We say so when that's the case, some projects we scope end up as conventional web apps with no blockchain at all, and that's a good outcome.
Practical uses we build
Memberships and access
Tokens that unlock content, events or features, transferable or tied to one holder.
Certificates and tickets
Verifiable credentials and event tickets that can't be forged.
Payments and tokens
Token contracts and payment flows with clear rules and limits.
Wallet sign-in
Sign-in with a wallet signature instead of a password, alongside normal accounts.
How blockchain & Web3 works, step by step
Every step has a clear output you can review. Timing is agreed in your quote.
- 1
Feasibility
Is blockchain needed, which network fits, and what are the risks?
- 2
Specification
Contract behaviour, roles and edge cases written down before code.
- 3
Contracts and tests
Contract development with extensive automated testing.
- 4
dApp
Front end, wallet connection and on-chain data indexing.
- 5
Testnet and review
Deployment to a test network and end-to-end testing.
- 6
Audit and mainnet
External audit where needed, fixes, then mainnet deployment.
Tools, and what shapes your quote
Pricing is based on your project and agreed in your quote. These are the things that move it.
| Factor | Why it matters |
|---|---|
| Contract complexity | Simple token contracts are quick; custom financial logic needs much more design and testing. |
| Network | Solana programs and EVM contracts use different languages and tooling. |
| Front end | A full dApp with dashboards adds web development on top of contracts. |
| Upgradeability | Upgradeable contracts add architecture and governance considerations. |
| Audit | External audits are a separate cost but essential for contracts holding real value. |
| Area | Tools |
|---|---|
| Contracts | Solidity, Rust (Anchor), OpenZeppelin |
| Testing & deployment | Foundry, Hardhat |
| Front end | Viem, wagmi, Ethers.js, WalletConnect, Phantom |
| Data & storage | The Graph, IPFS, Arweave |
Common mistakes to avoid
What we see go wrong most often, and how a good project avoids it.
Writing standards from scratch
Custom token implementations repeat solved problems and introduce bugs. Use audited libraries.
Skipping the audit
Contracts holding real value are prime targets. An independent audit is worth its cost.
Unlimited admin powers
Admin keys that can drain funds or change everything undermine user trust and create risk.
Using blockchain where a database would do
Adding a chain to a single-owner system adds cost and complexity without benefit.
Frequently asked questions
For contracts that will hold significant value, we strongly recommend an independent third-party security audit before mainnet launch. Audits are not included in our development estimates.
Which blockchain should I build on?
For most projects an EVM layer-2 such as Base, Arbitrum or Polygon gives Ethereum compatibility with low fees. Solana suits high-throughput consumer apps. We recommend based on your users, fees and the wallets they already have.
Is my smart contract secure?
We build on audited OpenZeppelin contracts, write full test suites with Foundry and follow established security patterns. For contracts that will hold significant value, we recommend an independent audit before launch.
Can you add blockchain features to an existing app?
Yes, wallet login, token-gated content or on-chain records, without rebuilding the rest of your product.
Do you build NFT projects?
Yes, focused on utility: memberships, tickets, certificates and loyalty, with minting pages and token-gated access.
Can contracts be changed after deployment?
Only if designed as upgradeable, which adds its own trust and security considerations. We agree the approach before development.
Do you build DeFi protocols?
We focus on simpler on-chain features such as tokens, staking and memberships. Complex financial protocols need specialist security resources; we'll be upfront about what we can responsibly deliver.
Do users need a crypto wallet?
Usually, but embedded and smart wallets can let users sign in with email while a wallet is created for them in the background.
Do you handle token launches or legal questions?
We handle the technical side. Token offerings involve securities and financial regulation, which require advice from qualified lawyers.
Who controls the deployed contracts?
You do. Admin roles are assigned to wallets you control, ideally a multi-signature wallet.
How much do transactions cost for users?
It depends on the network and activity. Layer-2 networks and Solana generally keep fees low; we estimate costs for your expected usage and can sponsor fees so users don't pay them directly.
Can you review contracts written by another team?
We can review code quality, add tests and prepare contracts for an independent audit. A formal security audit should still come from a specialist audit firm.
What happens if a bug is found after deployment?
That's why the upgrade or pause strategy is decided before launch. Upgradeable contracts can be patched through governance; immutable ones may need migration to a new contract.
Can you integrate fiat payments with crypto features?
Yes. Card payments can be handled by a standard payment provider while on-chain features run alongside, so users without crypto can still participate.
Related services
Blockchain & Web3 by industry
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Tell us what you need. You get an honest assessment, a clear plan and a written quote. The first consultation is always free.
- What happens next
- 1You tell us what you need
- 2We aim to reply within 24 hours with questions
- 3You get a written quote for your project