Protocol spec and invariants
Every rule the protocol must keep, written in plain English and approved before code starts.
The Problem
Your Protocol Can Pass Every Test and Still Get Drained
DeFi risk sits where unit tests rarely look: rounding in share math, a price read from one thin pool, and admin powers that can change everything overnight.
01 · Share math
First-deposit tricks can inflate share prices and take deposits.
Virtual shares and invariant tests stop rounding and donation attacks on vaults.
02 · Price feeds
A single pool's spot price moves with one flash loan.
Chainlink Data Feeds with freshness checks replace prices anyone can push around.
03 · Liquidations
Bad debt piles up when liquidations lag a falling market.
Liquidation paths get fuzzed with sharp price drops before launch.
04 · Admin powers
One key can change fees and limits overnight.
Admin roles sit behind a Safe multisig and a 48-hour timelock.
Your vault passed its unit tests on Tuesday. Deposits work, withdrawals work, and rewards accrue. Then a reviewer asks what happens if the first depositor donates tokens to inflate the share price, and nobody knows. Your lending module reads its price from a single pool that a flash loan can move for one block. The owner key can change fees and collateral limits with no delay. None of this shows up in a happy-path test, and all of it shows up on mainnet.
We start by writing the protocol's invariants: total assets cover total shares, nobody withdraws more than they put in plus earned rewards, and no position stays under-collateralized. Foundry invariant tests hammer those rules with random deposits, swaps, and price moves. Prices come from Chainlink Data Feeds with freshness checks, and admin changes wait behind a timelock. The economics get the same scrutiny as the code.
Economics tested like code
Share math, rewards, and liquidations checked by invariant tests with random market moves.
Fresh, checked prices
Chainlink Data Feeds read with staleness and bounds checks instead of one pool's spot price.
Admin changes on a delay
A Safe multisig and 48-hour timelock give users time to react to changes.
Our DeFi Development Services Process
From Protocol Spec to Mainnet Launch in Five Clear Steps
You approve the invariants before any code, see the economic test results before an audit, and control the launch from your own multisig.
We read your design doc, tokenomics, and any code you plan to fork, then ask where funds could leak. You get the main risks, the protocols worth integrating instead of rebuilding, and a fixed quote. If an audited protocol already does what you need, we'll tell you before we quote.
What's Included
What You Get From Our DeFi Development Solutions
Every build covers the spec and invariants, the contracts, economic tests, price feeds, admin controls, and the app your users touch, all documented for auditors.
Compare Options
DeveloperLook vs Forking a Protocol vs a Freelance Developer
Forking an audited protocol is fast, and a freelancer can be affordable. Here is where each one holds up once your own parameters, prices, and users' funds are involved.
| Feature | DeveloperLookBest fit | Fork as-is | Freelancer |
|---|---|---|---|
| Planning | Spec with economic invariants | The original protocol's docs | Varies by developer |
| Customization | Built to your parameters | Limited without new risk | Built to your rules |
| Economic testing | Invariant fuzzing with price moves | Original tests, not your changes | Often unit tests only |
| Speed to testnet | 4 to 5 weeks for one module | Days for an unchanged fork | Often fast for small jobs |
| Oracle setup | Chainlink feeds with freshness checks | Whatever the original used | Varies by developer |
| Admin controls | Multisig and 48-hour timelock | Copied from the original | Usually one deployer key |
| Support | 30 to 90 days after launch | Community and forum help | Depends on availability |
| Cost predictability | Fixed price after the spec | Lowest upfront cost | Hourly, can grow |
DeveloperLook
Fork as-is
- Planning
- DeveloperLook: Spec with economic invariantsFork as-is: The original protocol's docs
- Customization
- DeveloperLook: Built to your parametersFork as-is: Limited without new risk
- Economic testing
- DeveloperLook: Invariant fuzzing with price movesFork as-is: Original tests, not your changes
- Speed to testnet
- DeveloperLook: 4 to 5 weeks for one moduleFork as-is: Days for an unchanged fork
- Oracle setup
- DeveloperLook: Chainlink feeds with freshness checksFork as-is: Whatever the original used
- Admin controls
- DeveloperLook: Multisig and 48-hour timelockFork as-is: Copied from the original
- Support
- DeveloperLook: 30 to 90 days after launchFork as-is: Community and forum help
- Cost predictability
- DeveloperLook: Fixed price after the specFork as-is: Lowest upfront cost
Projects We've Built
Crypto Trading and NFT Projects We Have Built
Trading dashboards, a crypto portfolio app, and NFT marketplaces we designed and built. They show the wallet flows and transaction screens a DeFi app needs.
NFTIN NFT Marketplace App and Trading Dashboard
- Crypto & NFT
- Dashboard
- Mobile App
CoinSphere Crypto App Design & Development
- Crypto & NFT
- Dashboard
- Mobile App
ArtChain NFT Digital Arts Website & Dashboard
- Art
- Crypto & NFT
- Dashboard
PixelVault NFT Marketplace Web Design & Development
- Crypto & NFT
- Dashboard
- Website
What Our Clients Say
What Clients Say After Launch
Feedback from teams we have built websites, apps, and integrations for.
We had a pretty specific idea of what we wanted our website to become, but I wasn’t sure how easily we could explain all of it to a development team. There were quite a few moving parts, and we were working toward a deadline, so I expected a few things to get lost along the way. That never really happened. They understood what we were trying to achieve, kept us updated throughout the process, and got everything ready within the agreed timeline. The final site feels much easier to navigate, works beautifully on mobile, and is noticeably smoother for our customers. It was a huge relief seeing the original idea actually turn into the website we had in mind.
The mobile experience is probably my favourite part of the new site. We had spent a lot of time making sure the desktop version looked right, and the team kept pushing us to think about how everything would actually feel on a phone too. They were right. The navigation is clean, the interactions feel natural, and everything we’ve tested so far works exactly as it should. They also went through the links, forms, integrations, and other details more than once before launch, which I really appreciated. And even after going live, we could still reach out when something came up. The whole process felt friendly, organised, and surprisingly straightforward.
What I appreciate most is that the website is actually easy for us to manage now. We can update content ourselves instead of sending a developer a message every time we need to change something small. They also paid attention to the technical SEO side, which mattered to us because we didn’t want a new website to create problems for the traffic we already had. I’ve probably asked more questions than I should have since launch, but every question has been handled patiently and without any fuss. The team is easy to work with, they explain things clearly, and when we need something changed, they focus on getting it done rather than making the process complicated.
1,250+
Projects shipped
10+
Years of experience
Top 3%
Upwork Top Rated Plus
5 stars
Average review score
Want results like these?
Tell us what you are building. You get a reply within 24 hours on business days, then a written estimate.
Work Culture
Why DeFi Founders Trust Us With Pooled Funds
Pooled funds raise the stakes on every line of code. These habits keep the economics, prices, and admin powers of your protocol as tested as its functions.
We model the money first
Before code, we walk through deposits, rewards, and fees in a spreadsheet with you. If the numbers don't balance on paper, no amount of Solidity will fix them.
Attack thinking in every review
Each pull request answers one question: how would someone drain this? Flash loans, rounding, and reentrancy get checked on purpose, not by luck.
No yield promises
We don't write APY claims, return projections, or investment language into your app or docs. We build the mechanics and leave financial claims to you and your counsel.
Integrate before you rebuild
If an audited protocol already offers the pool or market you need, we integrate it instead of copying it. Less new code means less new risk.
Independent audits, coordinated
We prepare the audit pack, book the firm early, and fix the findings with you. We don't present our own testing as an audit.
Your signers, your protocol
We deploy from your Safe multisig and keep no admin role after launch. The timelock delay protects your users from us as well as from anyone else.
Overview
What do DeFi development services include?
DeveloperLook provides DeFi development services for founders building vaults, staking, lending, and swap products. We write the Solidity and test share math and oracle prices with invariant fuzzing. Your app ships wallet-connected, with admin powers behind a multisig and timelock. Projects start at $1,500, take 4 to 14 weeks, and audits come from independent firms.
DEVELOPERLOOK
Project facts · DeFi Development Services
- Service
- DeFi development services (protocol contracts, economic testing, dApp)
- Typical timeline
- 4 to 5 weeks for one module, 8 to 14 weeks for a full protocol
- Platforms
- Ethereum, Base, Arbitrum, and other EVM chains
- Built with
- Solidity, OpenZeppelin, Foundry, Chainlink Data Feeds, wagmi, and Safe
- Experience
- 10+ years of development experience and 1,250+ shipped projects
- Post-launch support
- 30, 60, or 90 days, depending on plan
- Communication
- Calls in US, UK, and AU business hours
- Starting price
- From $1,500 USD, fixed scope after a free protocol review
Reviewed 22 Oct 2026 by Saimul Islam
Good fit
Founders launching a vault or staking pool
You're launching a yield vault or staking pool and need the share and reward math proven before deposits arrive, not patched after.
Protocols adding lending or liquidations
Your protocol is adding borrowing, and you need collateral checks, liquidations, and oracle prices that hold up when markets move fast.
Teams adding swaps to their app
You want swaps inside your app, and you need a DeFi exchange development company that integrates existing pools before building a new one.
Founders hiring their first DeFi engineers
You're comparing freelancers and agencies and want DeFi smart contract development with written invariants, tests you can rerun, and a clear handover.
Agencies with a DeFi client
Your agency took on a DeFi client and needs Solidity and economic testing done quietly under your brand, with docs your team can present.
Not a fit
Simple token or airdrop
You only need a token, vesting, or an airdrop claim without pooled funds. Our Token Development Services page handles those for less.
No pooled funds involved
Your contracts handle memberships, escrow, or NFTs rather than pooled funds. Our Smart Contract Development Services team is the better fit.
Yield or return promises
You want us to promise users a yield, APY, or return, or to pitch token incentives as an investment. We build the mechanics and leave financial claims to you and your counsel.
Budget under $1,500
Your budget is under $1,500, or you plan to fork a protocol unchanged. Our Blockchain Consulting Services fit review costs less and shows what the fork still needs.
Not sure we're the right fit?
Book a free call or message us. We'll tell you honestly whether we're the right team.
Pricing
Transparent Starting Prices for DeFi Development Services
These are starting points in USD. Your final price depends on module count, the money logic involved, and chain count, and you get a fixed proposal after a free protocol review.
For teams that need one vault, staking pool, or rewards contract built and stress-tested.
$1,500one-time, USD
- Spec with economic invariants
- One vault, staking, or rewards contract
- Invariant fuzz tests with price moves
- Multisig and 48-hour timelock admin
- Testnet rehearsal and verified deploy
- 30 days of post-launch support
Recommended
For protocols that need up to 3 contracts, oracle prices, and a wallet-connected app for users.
$4,600one-time, USD
- Everything in Single DeFi Module
- Up to 3 interacting contracts
- Chainlink Data Feeds with freshness checks
- Wallet-connected web app with wagmi
- Mainnet fork tests and Slither report
- 60 days of post-launch support
For lending, exchange, or yield protocols launching on more than one chain with an audit.
$9,400one-time, USD
- Everything in DeFi dApp MVP
- Lending, liquidation, or AMM logic
- Web or mobile app with wallet features
- Deploys on up to 3 EVM chains
- Third-party audit coordination and fixes
- 90 days of post-launch support
For Agencies
White-Label Decentralized Finance Development Services for Agencies
You own the client relationship. We supply the DeFi engineering behind it: protocol specs, Solidity, economic stress tests, and the app, delivered under your agency name with documentation an auditor can work from.
How the partnership works
White label: your client only ever sees your brand
- Your client
- You, the agency
- DeveloperLook
Share the protocol brief
Send the client's design doc, tokenomics, target chains, and any code they plan to fork.
- Client needs
- You share the details
- Details received
We spec and stress-test
You get a fixed quote, then we build and run economic tests on a testnet.
- Scope and plan
- Proposal to resell
- Your quoteYOUR LOGO
You present the launch
Your team presents the protocol and audit pack under your brand, with our support.
- Done by our team
- Your brand on it
- Handed to your clientDone
Partner with DeveloperLookDelivered under your brand
Stay client-facing
Your brand on the spec and test reports, and we stay off client calls.
Predictable delivery
Fixed scope per module, with invariant and testnet milestones dated in the plan.
Economic testing included
Invariant fuzzing with price moves comes standard, not as an expensive add-on.
Flexible capacity
Take on DeFi clients without hiring Solidity and quant specialists yourself.
The Right Technology for Your Project
Technology Stack
We build on audited libraries and established price feeds, so the new code in your protocol stays as small as possible.
- Solidity
- OpenZeppelin
- Foundry
- Slither
- Chainlink
- Ethereum
- Base
- Arbitrum
- Safe multisig
- Timelock
- WalletConnect
- Explorer verification
Next.js
TypeScript- wagmi
- ethers.js
React Native
FAQ
Frequently Asked Questions
Straight answers on cost, timelines, building DeFi apps, hiring developers, yield contracts, and wallets.
Saimul IslamFounder & CEO, DeveloperLookStill have questions?
Send a message or book a call with the team.
DeFi development services with DeveloperLook start at $1,500 for one vault, staking, or rewards contract with invariant tests and a timelocked admin. Up to 3 contracts with oracle prices and a wallet-connected app start at $4,600. Full lending, exchange, or yield protocols on up to 3 chains, with audit coordination, start at $9,400. Audit fees go to the audit firm directly.
One module takes 4 to 5 weeks from the free review to mainnet. A DeFi dApp MVP takes 8 to 10 weeks, and a full protocol on several chains takes 12 to 14 weeks before the audit. Independent audits have their own queues, so we book the firm while the spec is still being written.
DeFi development means building lending, trading, staking, and payment products whose rules live in smart contracts on a public blockchain. Users keep custody through their own wallets, and the contracts hold the pooled funds. That makes the work part software engineering and part financial engineering, because incentives and price inputs matter as much as the code.
DeFi app development happens in two layers: the contracts that hold funds and the app users touch. The contracts come first, with written invariants, Foundry tests, and oracle checks. Then we build the web app with wagmi, so deposits, borrows, and swaps show clear pending, confirmed, and failed states. Both layers rehearse on a testnet before mainnet.
Start by checking what you can build on instead of writing new money logic. Many DeFi apps integrate audited lending markets, DEX pools, or ERC-4626 vaults rather than deploying their own. We build the interface, the routing, and any thin contracts you need, which cuts both cost and risk. If you truly need something new, we scope it separately.
Hire DeFi developers by testing how they think about attacks, not only how fast they write Solidity. Ask for a past invariant test suite, how they would stop a first-depositor attack on a vault, and how they read oracle prices. A good DeFi development company also tells you what to integrate instead of build.
Find a DeFi developer through work you can inspect: verified contracts on a block explorer, public audit reports that name them, and open-source test suites. Freelance boards and agencies both work if you check that evidence first. Whoever you pick, keep admin keys in your own multisig so trust isn't your only safeguard.
Look for DeFi smart contract development experience, not general Solidity alone. The developers should explain vault share accounting, oracle failure modes, liquidation incentives, and how bots reorder transactions to extract value (MEV). Ask them which invariant they would test first. If you want the work done rather than staffed, our team takes it on at a fixed price.
Yes. We build staking pools, reward distributors, and liquidity mining contracts, the work a DeFi yield farming development company is usually hired for. We test reward math for rounding, late joiners, and emergency withdrawals. We don't set or promise reward rates: you choose the parameters, and the contracts enforce them exactly.
Yes, as features of your DeFi app. We add swap screens that route through existing DEX pools, plus wallet features such as balances, approvals, and transaction history in web or mobile apps. If you need a DeFi wallet development company for a standalone wallet product, we scope that as its own project.
Saimul IslamFounder & CEO, DeveloperLookStill have questions?
Send a message or book a call with the team.
Free 30-min callGoogle Meet
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