Audited smart contracts, dApps, tokenization platforms and enterprise ledgers on Ethereum, Layer 2s, Solana and Hyperledger Fabric. Designed, secured and shipped by one team, and connected to the systems your business already runs.
Blockchain development services cover designing, building, testing and running software that records transactions on a distributed ledger. That includes the smart contracts that hold the rules and the value, the web and mobile apps people use to interact with them, the wallets and integrations that connect them to existing systems, and the security work that has to happen before anything reaches mainnet.
A smart contract cannot be patched like a web server once it is live and holding funds, so most of the engineering effort goes into design, testing and review rather than writing code. Appther runs blockchain work through the same security-first process we use across our custom software development, under an ISO/IEC 27001-certified information security management system.
Our Blockchain Development Services
Eight service lines, from a single token contract to a network shared by several companies. Pick one to see what we build and how it looks in practice. Need engineers inside your own team instead? See hire blockchain engineers.
Staking, vaults and lending logic with liquidation safeguards
Stablecoin payment, payout and settlement rails
Chainlink price feeds with staleness and deviation checks
Pause switches, rate limits and treasury multisig from day one
#00120.08 ETH
#0207Listed
#03180.12 ETH
#0451Sold
ERC-721 · EIP-2981 royalties
05 · Service line
NFT Platforms & Marketplaces
Collections, lazy minting and reveal mechanics that resist front-running
Marketplaces with listings, offers, royalties and creator payouts
Metadata on IPFS so the asset outlives any single server
Loyalty passes and ticketing where NFTs replace a database row
Hyperledger Fabric · private channels
06 · Service line
Enterprise & Private Blockchain
Hyperledger Fabric networks with private channels per relationship
Permissioned EVM chains when partners need Ethereum tooling
Chaincode in Go or Node.js, with roles mapped to real organisations
Traceability and audit trails that regulators and partners can verify
Treasury transfer250,000 USDC
CFO ✓CTO ✓COO
2 of 3 signatures · executes after 24h timelock
07 · Service line
Wallets, Custody & Integration
Multisig treasuries with timelocked execution for company funds
Integrations with custody and wallet providers instead of raw key handling
Event listeners and reconciliation into ERP, CRM and accounting
Monitoring and alerts on contract events after launch
Security review · v1.2
CriticalReentrancy in withdraw()Fixed
HighUnchecked oracle stalenessFixed
MediumMissing event on role changeFixed
LowGas: cache array lengthFixed
08 · Service line
Smart Contract Audit & Review
Review of contracts you already have, before or after deployment
Severity-ranked findings with a fix for each one
Fuzz and invariant tests added where coverage is thin
Preparation and remediation support for an external audit firm
Business Case
What Are the Benefits of Blockchain for Business?
A blockchain is slower and more expensive than a database, so it has to buy something a database cannot. These are the four things it does well.
A record nobody can quietly edit
Once a transaction is confirmed it cannot be changed without everyone seeing it. That makes the ledger itself the audit trail, which is why regulators and partners accept it.
Tamper-evident history
Fewer reconciliation disputes
Shared truth between companies
When suppliers, banks or partners each keep their own copy, they spend weeks reconciling. One shared ledger replaces the back-and-forth with a single version everyone can check.
No duplicate records
Faster partner settlement
Automated settlement and payouts
Smart contracts pay out, release escrow or distribute income the moment the agreed conditions are met, without an intermediary holding the money in between.
Payouts in minutes, not days
Lower intermediary fees
Assets people can own and trade
Tokenization turns property, fund shares or loyalty points into assets that can be split, transferred and held in a user's own wallet, within the rules you set.
Fractional ownership
Transfer rules enforced in code
Block 18,402,1170x7a3f…9c1e142 txns
Block 18,402,1180x91bd…e04a98 txns
Block 18,402,1190x0c55…3b7f211 txns
Production Systems, Not Testnet Demos
A contract that works on a testnet is not a product. Six disciplines take a blockchain idea to something that holds real value safely, backed by our mobile, API and cloud teams.
[1]Chain selection & token design
Ethereum, a Layer 2, Solana or a private network is chosen on your users, assets and rules, and explained in writing. Token supply, vesting and permissions are designed before any contract is written.
[2]Smart contract engineering
Solidity and Rust written on audited libraries, with upgrade and admin models agreed up front. Gas is optimised where it changes user cost, not as a vanity metric.
[3]Off-chain backend & indexing
Most of a blockchain product is ordinary software. Indexers, APIs and databases make it fast; only the rules that must be shared and tamper-proof go on-chain.
[4]Wallet UX & onboarding
Embedded wallets, social login and gasless transactions remove the steps that lose most first-time users, while experienced users can still bring their own wallet.
[5]Security, testing & audit
Threat model, fuzz and invariant tests, static analysis, internal review and an external audit, with evidence for each step handed to you.
[6]Launch, monitoring & upgrades
Staged mainnet deployment, multisig admin keys, on-chain monitoring and alerts, and a governed path for upgrades after launch.
Free Blockchain Feasibility Review
Not Sure You Need a Blockchain? That Is the Right First Question.
In one call we look at your idea and tell you honestly whether a blockchain adds anything a normal database would not. If it does, you leave with the right chain, an architecture sketch and a budget range. If it does not, we will say so.
Free · No obligation · Written summary within 48 hours
Decision Guide
When Does a Blockchain Make Sense?
A blockchain earns its cost when several parties who do not fully trust each other need to share one record. If one company controls all the data, a conventional database is faster and cheaper.
Good fit
Several companies or users write to the same record
Ownership of an asset must be provable and transferable
An audit trail must be tamper-evident to outsiders
Settlement or payouts should run without a middleman
Users want to hold their own assets in their own wallets
Probably not needed
One organisation owns and edits all the data
Records need to be deleted or changed often
Data is highly confidential and cannot be shared at all
You need thousands of private writes per second at low cost
The main goal is “being on blockchain” for marketing
Our Process
How We Deliver Blockchain Projects, Step by Step
Every phase ends with something you can review. Nothing touches mainnet until the code has passed testing, review and, for anything holding value, an external audit.
1
Week 1–2
Discovery & Threat Model
We confirm a blockchain is the right tool, choose the chain, and map who can move value and how it could go wrong.
2
Week 2–3
Architecture & Token Design
Contract interfaces, upgrade and admin model, tokenomics and the on-chain versus off-chain split are agreed in writing.
3
Week 3–10
Build & Test
Contracts, app and integrations in weekly sprints, with unit, fuzz and invariant tests written alongside the code.
4
Week 9–14
Testnet, Review & Audit
Public testnet deployment, internal security review, external audit and fixes before anything goes live.
5
Launch & after
Mainnet & Monitoring
Staged mainnet launch with multisig-controlled admin keys, on-chain monitoring, alerts and ongoing support.
How We Work
Standards Behind Every Contract
8
Security gates
From threat model to launch controls, with evidence for each one handed over at the end.
6+
Chains supported
Ethereum, Layer 2s, Polygon, BNB Chain, Solana and Hyperledger Fabric, chosen on fit.
100%
Code & keys yours
Repositories, deployer accounts and admin keys transfer to a multisig you control.
ISO
27001 certified
Delivered under an ISO/IEC 27001-certified information security management system.
Related Work
Secure Payment & Ledger Products We've Shipped
Not blockchain projects, and we will not pretend otherwise. These are the money-moving, ledger-heavy systems where we built the same discipline a blockchain product needs.
The questions worth asking any team you shortlist, and how we answer them.
We tell you if you don't need one
Our first job is to check whether a blockchain adds anything a normal database would not. If it doesn't, we say so and save you the build.
Honest feasibility review
Database alternative costed
Security is the project plan
Threat model, fuzz tests, static analysis and an external audit are scheduled into the timeline from week one, not squeezed in before launch.
Seven security gates
Audit time budgeted
One team, contracts to apps
Contracts, web and mobile apps, backend and integrations are built by one team, so nothing breaks at the hand-off between on-chain and off-chain code.
No integration blame gap
Mobile, web and cloud in-house
Your keys, your code
Repositories, deployer accounts and admin keys belong to you from the first commit. At launch, admin rights move to a multisig you control.
100% code and IP ownership
ISO 27001-certified delivery
Smart Contract Security
How Do We Keep Smart Contracts Secure?
Smart contract bugs are paid for in lost funds, not support tickets. Every contract passes these eight gates before mainnet, and you get the evidence for each one.
Threat model
Who can call what, which keys hold power and what an attacker would try first, written down before code.
Roles and privileges mapped
Attack paths ranked
Battle-tested libraries
OpenZeppelin and established standards instead of hand-rolled access control, maths or token logic.
Audited base contracts
Standard interfaces
Unit & integration tests
Every function and every failure path covered, running in CI on each change.
Revert paths tested
Runs on every commit
Fuzz & invariant tests
Foundry throws millions of random inputs at the contracts and checks the rules that must never break.
Property-based testing
Invariants on balances
Static analysis
Slither and similar tools catch known vulnerability patterns before a human reviewer starts.
Known-bug detection
Gas and style checks
Internal review
A second engineer who did not write the code reviews every line against the threat model.
Four-eyes on every change
Findings tracked to fix
Independent audit
An external audit firm of your choice reviews before mainnet, and every finding is fixed and re-checked.
External firm, your choice
Remediation included
Launch controls
Multisig admin keys, timelocks on upgrades, pause switches and live monitoring with alerts.
Established, well-audited tools only. On a chain, the boring choice is usually the safe one. Pick one to see where it fits.
Solidity & the EVM
The language of Ethereum and every EVM chain: Arbitrum, Optimism, Base, Polygon and BNB Chain. Written on OpenZeppelin, tested with Foundry and Hardhat, and checked with Slither. One codebase can deploy to several EVM chains when your users are spread across them.
Rust & Solana (Anchor)
For high-throughput trading, payments and real-time apps where fees must stay near zero. Anchor gives Solana programs a safer structure, and Rust's type system rules out whole classes of bugs before deployment.
Layer 2 networks
Arbitrum, Optimism and Base process transactions cheaply and settle back to Ethereum for security. The usual home for consumer apps, payments and loyalty, where Ethereum mainnet fees would price users out.
Hyperledger Fabric
A permissioned blockchain for consortia and supply chains where members are known and data stays private. Chaincode in Go or Node.js, private channels per relationship and no gas fees.
Oracles, indexers & storage
Chainlink for prices and outside events, The Graph for fast queries over on-chain data, and IPFS for files and metadata that should outlive any single server.
Wallets & app layer
ethers.js, viem and wagmi on the web, WalletConnect for mobile wallets, embedded wallets for email login, and React, Next.js, Flutter or React Native for the apps people actually use.
Security tooling
Foundry fuzzing and invariant testing, Slither and Aderyn static analysis, Tenderly simulation and monitoring, and Safe multisig for every admin key we hand over.
Platform Guide
Which Blockchain Should You Build On?
There is no best chain, only the right one for your users, your assets and your rules. This is how we usually narrow it down.
Blockchain platforms compared
Platform
Type
Contract language
Transaction cost
Best for
Ethereum
Public, Layer 1
Solidity, Vyper
Highest
High-value assets and DeFi where security and liquidity matter most
Arbitrum, Optimism, Base
Public, Ethereum Layer 2
Solidity
Low
Consumer apps and payments that need Ethereum security at lower fees
Polygon PoS
Public, EVM chain
Solidity
Very low
NFTs, loyalty and high-volume consumer transactions
BNB Chain
Public, EVM chain
Solidity
Low
Apps targeting the BNB user base and exchange ecosystem
Solana
Public, Layer 1
Rust (Anchor)
Very low
High-throughput trading, payments and real-time apps
Hyperledger Fabric
Private, permissioned
Go, Node.js, Java
No gas fees
Consortia and supply chains where members are known and data stays private
Cost & Timeline
How Much Does Blockchain Development Cost?
Indicative ranges for the projects we are asked about most. Your fixed quote comes after discovery, once the scope is written down.
Typical scope
Token or simple smart contract
$8K – $25K
3 to 6 weeks
An ERC-20 or NFT collection contract with tests, deployment scripts and a basic admin panel.
Typical scope
dApp or NFT marketplace
$25K – $70K
8 to 14 weeks
Contracts plus a full web or mobile app, wallet flows, indexing and an admin dashboard.
Most requested
Tokenization platform
$50K – $120K
12 to 18 weeks
Asset tokens with transfer restrictions, investor onboarding, distributions and compliance reporting.
Typical scope
DeFi protocol or enterprise network
$80K – $200K+
16 to 24+ weeks
Multi-contract protocols or permissioned networks with several organisations, integrations and governance.
Ranges exclude third-party costs: external audit fees, gas for deployment, and node or custody provider subscriptions. What moves the price most: the number of contracts, how much value they will hold, the number of chains, and the systems to integrate.
Use Cases
Blockchain Use Cases by Industry
Where a shared, tamper-evident ledger solves a real business problem, and what we build for it. For payment products without a blockchain, see fintech app development.
[01]Finance & FinTech
Programmable money and faster settlement, built to pass a bank's security review.
The building blocks that show up in most blockchain products we scope, from first wallet connection to the controls that protect the treasury.
Wallet Connect & Login
Email & Social Wallets
Gasless Transactions
Multisig Admin
Timelocked Upgrades
Emergency Pause
KYC & Whitelists
Token Vesting
Staking & Rewards
On-Chain Governance
Event Notifications
Indexed Search
IPFS Metadata
Cross-Chain Bridging
Royalties & Fees
On-Chain Analytics
Proof & Verification
Admin Dashboard
Architecture
Blockchain App Architecture, Layer by Layer
Only the rules that must be shared and tamper-proof go on-chain. The other nine layers are what make a blockchain product fast, cheap and usable.
App & Interface
Web and mobile screens that turn signatures and confirmations into something a normal person can follow.
01
Wallet Layer
External wallets, embedded wallets or custody providers, chosen on who your users are.
02
Relayer & Paymaster
Sponsors gas or batches transactions, so users are not asked to buy a token before they start.
03
Smart Contracts
The rules and the value. Small, audited and changed only through governed upgrades.
04
Admin & Governance
Multisig, timelocks and roles that decide who can change what, and how fast.
05
Oracles
Prices and outside events brought on-chain, with checks for stale or manipulated data.
06
Indexer
The Graph or a custom indexer so the app can query history without waiting on the chain.
07
Backend & APIs
Ordinary services for profiles, notifications and anything that does not need to be on-chain.
08
Business Integrations
Event-driven links to ERP, CRM, accounting and payment systems, with reconciliation.
09
Monitoring
Alerts on unusual contract calls, failed transactions and admin actions, around the clock.
10
App & Interface
Web and mobile screens that turn signatures and confirmations into something a normal person can follow.
01
Wallet Layer
External wallets, embedded wallets or custody providers, chosen on who your users are.
02
Relayer & Paymaster
Sponsors gas or batches transactions, so users are not asked to buy a token before they start.
03
Smart Contracts
The rules and the value. Small, audited and changed only through governed upgrades.
04
Admin & Governance
Multisig, timelocks and roles that decide who can change what, and how fast.
05
Oracles
Prices and outside events brought on-chain, with checks for stale or manipulated data.
06
Indexer
The Graph or a custom indexer so the app can query history without waiting on the chain.
07
Backend & APIs
Ordinary services for profiles, notifications and anything that does not need to be on-chain.
08
Business Integrations
Event-driven links to ERP, CRM, accounting and payment systems, with reconciliation.
09
Monitoring
Alerts on unusual contract calls, failed transactions and admin actions, around the clock.
10
Client Voices
What Clients Say About Working With Appther
“Appther exceeded every expectation, on time and on budget, and the final product has been instrumental in scaling our business. A rare engineering partner.”
Johnathan PefferCEO · Bull's Eye Technologies Inc
“Rolling out a platform across our operations felt daunting at first, but Appther made the transition seamless. Every department now works off a single source of truth.”
Pushpender KumarGeneral Manager · A.B. Sugars Ltd
“Appther built our student competition platform exactly the way we envisioned it: easy registration, smooth judging, and real-time results that keep participants engaged.”
Dionna MilemOwner · My BOB Team LLC
“Building a mental health product means every detail has to be handled with care, and Appther got that from day one. The product feels warm, simple, and genuinely helpful.”
Bob SinghalProfessor of Joy · Joyscore Inc
Glossary
Blockchain Terms in Plain English
Smart contract
A program stored on a blockchain that runs exactly as written when someone calls it, and holds or moves assets by its own rules.
dApp
A decentralised application: a normal web or mobile front end whose core logic runs in smart contracts.
Gas
The fee paid to the network to run a transaction or contract call, priced by how much computation it uses.
Layer 2
A network such as Arbitrum or Base that processes transactions cheaply and settles them back to Ethereum for security.
Oracle
A service, such as Chainlink, that brings outside data like prices or events onto the blockchain for contracts to use.
Tokenization
Representing ownership of an asset, such as property, a fund share or loyalty points, as a token on a blockchain.
Smart contract audit
An independent security review of contract code to find vulnerabilities before it is deployed and holds value.
Permissioned blockchain
A private network, such as Hyperledger Fabric, where only approved organisations can join, read and write.
Latest Insights
Reading on Blockchain & FinTech
Background reading from our team on blockchain, digital assets and secure financial products.
Building payment and wallet products that pass security review
Free 30-Minute Blockchain Strategy Call
Have a Blockchain Idea? Let’s Pressure-Test It.
One call gets you an honest view on whether a blockchain fits, which chain to use, how to keep it secure, and what it will cost to build. No pitch deck, no obligation.
Blockchain development services cover choosing the right chain, designing and writing smart contracts, building the web or mobile app users interact with, connecting wallets and existing business systems, security testing and audit preparation, deployment to mainnet, and monitoring and support after launch.
A token or simple smart contract typically costs $8K to $25K. A dApp or NFT marketplace runs $25K to $70K, a tokenization platform $50K to $120K, and a DeFi protocol or multi-company enterprise network $80K to $200K or more. External audit fees, deployment gas and node or custody provider costs are extra. You get a fixed quote after discovery.
A token contract with tests takes about 3 to 6 weeks. A dApp or marketplace takes 8 to 14 weeks, and tokenization platforms, DeFi protocols and enterprise networks take 12 to 24 weeks or more, including testnet deployment, review and an external audit.
It depends on what you are building. Ethereum suits high-value assets and DeFi, Ethereum Layer 2s such as Arbitrum, Optimism and Base suit consumer apps that need low fees, Polygon suits NFTs and loyalty, Solana suits high-throughput trading and payments, and Hyperledger Fabric suits private consortia where members are known. We recommend a chain in discovery based on your users, assets and rules.
Only if several parties who do not fully trust each other need to share one record, if ownership of an asset must be provable and transferable, or if an audit trail has to be tamper-evident to outsiders. If one organisation controls all the data, a conventional database is faster and cheaper, and we will tell you so in the free feasibility review.
Every contract goes through a threat model, uses audited libraries such as OpenZeppelin, and is covered by unit, fuzz and invariant tests in Foundry. Static analysis with Slither and an internal review by a second engineer come next, then an external audit before mainnet. Launch uses multisig admin keys, timelocks on upgrades, pause switches and live monitoring.
We prepare contracts for audit and fix every finding, and we review existing contracts for clients. For anything that will hold significant value we recommend an independent external audit firm in addition to our own review, because a second, separate team catches what the authors miss.
Yes. We build event listeners, APIs and reconciliation jobs that connect smart contracts to ERP, CRM, accounting and payment systems, so on-chain activity updates your business records and your systems can trigger on-chain actions without manual re-entry.
This page is for a delivered project: Appther owns the scope, architecture, security process and delivery for a fixed price. If you already have a team and a plan and just need extra Solidity or Web3 engineers working under your direction, see our hire blockchain engineers service instead.
You do. You own 100% of the source code, contracts, deployment keys and intellectual property. Admin keys are handed over to a multisig you control at launch, and we sign an NDA before discovery if you need one.
