Crypto DeFi wallet · engineering partner
Web3 wallet development services,
engineered as a product you own.
TrustChange is a crypto DeFi wallet development company for EU-facing crypto startups, licensed VASPs, PSPs, EMIs, neobanks and banks. We build Web3 wallets under your brand — the app, the non-custodial signing model, the chain adapters, the DeFi and dApp connectivity, the ramps and the compliance controls — as bespoke software, not a SaaS licence with a per-user fee. You get a wallet your product team can extend, your ops team can support and your auditor can read.
- EU-based engineers
- MiCA-aware architecture
- Travel Rule aware
- GDPR-aware storage
What "Web3 wallet" means here
Custodial versus Web3 / DeFi — the honest comparison
Most searches for crypto DeFi wallet development services expect a non-custodial wallet with first-class dApp connectivity — the user holds the keys and interacts with DeFi directly. Below is how a Web3 wallet differs from a custodial venue wallet in the parts that shape the build. TrustChange builds both; this page is for the Web3 shape.
Building a custodial wallet instead? See crypto wallet app development, white label crypto wallet development and the wider wallet and custody engineering practice. Company-level view: crypto wallet development company.
| Dimension | Custodial | Web3 / DeFi |
|---|---|---|
| Custody | Venue holds keys, user has balance on venue ledger | User holds the keys (seed, secure-enclave or MPC share) |
| Recovery | Venue-side dispute + support paths | Seed backup or MPC social recovery — chosen up front |
| DeFi & dApps | Limited, mediated by the venue | First-class: WalletConnect, dApp browser, EIP-6963 |
| KYC | Required at onboarding | Only where a regulated flow requires it (e.g. fiat ramp, custodial add-on) |
| Fiat rails | Bank rails through the venue | Ramps via licensed on/off-ramp partners |
| Fit | Retail and pro trading, licensed operators | Self-custody, DeFi access, dApp-native products |
Product surface
Three surfaces in every crypto DeFi wallet development services engagement
A Web3 wallet is not one app. It is the customer-facing product, the DeFi connectivity layer and the internal APIs your product and support team live behind. We ship all three as one product, on one architecture, with one team accountable end to end.
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01
Web3 wallet app
iOS, Android and web wallets under your brand: onboarding, seed backup or MPC key model, dApp browser, WalletConnect, send / receive / swap / stake and portfolio views.
- Native mobile + web
- WalletConnect + dApp browser
- Design tokens per tenant
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02
DeFi integrations
Adapters into DEX aggregators, AMM pools, lending protocols, staking contracts and bridges — designed for safe defaults, human-readable prompts and revocable approvals.
- DEX & AMM adapters
- Staking & lending
- Bridge adapters
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03
Ops console & APIs
The internal console your product and support team runs the wallet from — user support tools, safe-mode toggles, allow-lists — plus signed APIs for extensions.
- Role-based access
- Safe-mode toggles
- Signed REST + webhooks
Stack
What sits behind a Web3 wallet
Eight layers, one system. Every layer names an owner, a control and a piece of audit evidence — nothing is left implied under the "Web3" label.
Delivery patterns and evidence: how we deliver. Wider platform view: fintech infrastructure. Fiat-in and fiat-out flows: on- and off-ramp integration. Related builds: blockchain app development services and smart contract development services.
| Layer | What we build |
|---|---|
| Product surface | iOS, Android and web wallets under your brand, driven by design tokens per tenant One product surface, no shared multi-tenant backend behind it. |
| Signing model | Non-custodial by default: seed-phrase, secure-enclave key storage or MPC (threshold) signing with the user as a party Custody sits with the user; venue-side custody is optional and clearly labelled. |
| Chain coverage | Bitcoin, EVM chains (Ethereum, L2 rollups, side chains), Solana and other account or UTXO networks New chains land as plug-ins on one wallet core, not a fork. |
| DeFi connectivity | WalletConnect, EIP-6963, dApp browser, DEX aggregator, AMM, lending and staking adapters Human-readable prompts, session controls and revocable token allowances. |
| Ramps & liquidity | Card, SEPA and open-banking rails routed through partner PSPs and licensed on/off-ramp providers Quotes lock a rate for a set window; ramp adapters plug into one router. |
| Compliance controls | KYC/KYB where the model requires it, sanctions and wallet-risk screening, Travel Rule messaging on transfers Non-custodial does not mean rule-free — screening runs before regulated actions. |
| Notifications & data | Push, email and in-app notifications, event stream and warehouse loads One canonical event stream, versioned schemas. |
| Runtime & delivery | EU-hosted, CI/CD pipelines, observability, 24/7 on-call cover Your identity provider, your data regions, your app-store identifiers. |
Transaction path
How a Web3 transaction crosses the wallet
Every intent in the Web3 wallet — a swap, a stake, a contract call, a bridge — goes through the same gates before a signature happens. Speed comes from tuning the pipeline, not from skipping a step or hiding the intent from the user.
- 01
Intent
Real time
A user starts a swap, transfer, stake or contract call from the wallet app or a connected dApp.
- 02
Preview
Sub-second
The wallet builds a human-readable prompt — asset, amount, destination, contract, allowance, estimated gas.
- 03
Screening
Sub-second
Sanctions and wallet-risk vendors return a verdict where regulated flows apply; the reason is stored with the request.
- 04
Sign
User action
The user signs locally (secure-enclave, seed or MPC share); the key never leaves the user's boundary.
- 05
Broadcast
Chain-bound
The signed transaction goes on chain; the wallet watches inclusion, revert or replacement.
- 06
Reconcile
Immediate
Portfolio updates from indexer reads; every session and approval is logged and revocable in the app.
Delivery
How we deliver a crypto DeFi wallet development project
Five steps, in this order. Web3 wallet work runs inside the product backlog — no separate compliance phase bolted on before launch, no big-bang release of an untested Web3 wallet.
- 01
Scoping
Weeks 1–2
We map users, chains, DeFi protocols, custody model, ramps, licence context and the risk you must stand behind. Output: a scope, a control map and a costed plan.
- 02
Architecture
Weeks 3–4
Signing model, chain adapters, DeFi flows, dApp session controls and screening flow written down first. Regulatory constraints shape the design.
- 03
Build
Two-week sprints
Product surface, signing, chain adapters, DeFi integrations and admin ship in slices. Each merge runs tests, static checks and a dependency scan.
- 04
Hardening
Before launch
Contract-integration audit where relevant, load work, failure drills, recovery rehearsal and a third-party pen-test window.
- 05
Launch and run
Cutover + ongoing
Named engineers on 24/7 cover. Runbooks, dashboards, release playbooks and the audit log are handed to your team on day one.
Engagement
Four ways to buy your Web3 wallet build
Same engineers, same standard. Only the commercial shape changes.
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Fixed-scope build
A defined Web3 wallet at a fixed price and date. Best when chains, DeFi protocols and rails are settled.
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Dedicated team
A standing squad with a lead. Best for long roadmaps and new chains or protocols each quarter.
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Staff augmentation
Senior engineers inside your team. Best when you already own the plan and need Web3 depth.
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CTO advisory
Architecture and buy-vs-build review before you commit. Best at the design stage.
Questions
FAQ: Web3 & crypto DeFi wallet development services
Six answers up front on scope, off-the-shelf trade-offs, chains & DeFi flows, keys & safety, compliance under non-custodial models and support. Bring the rest to the call.
What do crypto DeFi wallet development services from TrustChange actually cover?
We engineer a bespoke, client-owned Web3 wallet end to end: the mobile and web surface, the non-custodial signing model (seed, secure-enclave or MPC), the chain adapters, the DeFi integrations (WalletConnect, DEX aggregators, staking, lending, bridges), the ramps and the compliance controls where a regulated flow needs them. It ships as source code in your repositories, with the IP assigned to you and app bundles signed under your own Apple and Google identifiers.
How is your crypto DeFi wallet development company different from an off-the-shelf provider?
Off-the-shelf Web3 wallet providers usually bundle a generic app with a hidden backend and hand you a licence. TrustChange engineers the app, the signing model, the indexer, the DeFi adapters and the controls against your actual use case — chains, protocols, licence context and audit expectations. A bespoke build takes longer up front, but you keep every line of code, every adapter and every deployment decision, and you avoid the vendor gate that comes with a packaged Web3 wallet.
Which chains, protocols and DeFi flows does the Web3 wallet cover?
Bitcoin, EVM chains (Ethereum, L2 rollups, side chains), Solana and other account or UTXO networks land as plug-ins on one wallet core. Standard DeFi flows include swap via DEX aggregators or direct AMM pools, staking and delegated staking, lending and borrowing protocols, bridges between chains and NFT interactions where the product needs them. WalletConnect and EIP-6963 provide dApp connectivity with revocable session controls and readable prompts.
How do keys, recovery and dApp safety work in the Web3 wallet you deliver?
The default is non-custodial: keys are generated on the device (secure-enclave-backed) or as an MPC share with the user as a party, and never leave the user's boundary. Recovery is chosen up front — seed backup, MPC social recovery, or a hybrid — with clear UX and a rehearsed rollback. dApp safety includes human-readable transaction previews, revocable token allowances, session listing and safe-mode toggles for high-risk chains or contracts.
How are MiCA, PSD2, AML/Travel Rule and GDPR engineered in when the wallet is non-custodial?
Non-custodial does not mean rule-free. TrustChange is an engineering partner, not a law firm — your legal advisers and MLRO set the policy, we ship the controls and the evidence. Where a regulated flow applies (fiat ramps, custodial add-ons, KYC-gated products), we ship KYC/KYB, sanctions and wallet-risk screening, Travel Rule data on transfers, PSD2-aware fiat flows and GDPR-aware storage with retention rules. Where the flow is fully self-custody, controls are engineered against your policy and disclosed to users transparently.
Do you also run the Web3 wallet after launch, or hand it over?
Both are on the table. Most clients start with named TrustChange engineers on 24/7 cover during the first months while their own team ramps up, then take the platform in-house with runbooks, dashboards, release playbooks and the audit bundle. Some keep us on as a dedicated development team or on staff augmentation for new-chain, new-protocol and roadmap work, or as CTO advisory on architectural calls.
Book a discovery call for Web3 wallet development services
Bring the chain list, the DeFi protocols in scope, the licence context, the target markets and the launch date. We come back with a control map, an architecture view and a costed plan for a Web3 wallet you own end to end. No demo theatre.