Blockchain development company & Web3 services · engineering partner
Web3 product engineering services,
engineered as a product you own.
TrustChange is a blockchain development company and Web3 services partner for EU-facing crypto startups, licensed VASPs, PSPs, EMIs, neobanks and banks. A standing EU squad under a named delivery lead builds the whole Web3 product — consumer and operator apps, smart contracts, off-chain services, fiat rails, wallet and custody, compliance controls — as bespoke software under your brand. Not a rented SaaS. Not a single-shot dApp. A product.
- EU-based engineers
- Named delivery lead
- MiCA-ready architecture
- AML & Travel Rule aware
- GDPR-aware storage
What "product engineering" means here
A blockchain development company and Web3 services partner, not a contract shop
Most searches for a blockchain development company and Web3 services partner surface single-focus vendors — a contract shop, a wallet SaaS, a bridge builder. TrustChange works as the product-engineering shape: one team ships the whole product — app, contracts, off-chain services, rails, custody, controls — with regulated-industry delivery discipline. What you buy is engineering across the whole surface, not one component.
Deciding whether to buy, build or wrap? Start with CTO advisory. Adjacent shapes: blockchain app development services, blockchain development outsourcing services, Web3 wallet development services and, for company-level positioning, crypto software development company.
Product surfaces
Four surfaces in every Web3 product engineering services engagement
A Web3 product is not one artefact. It is the customer and operator apps, the contracts on chain, the off-chain services that keep the two in sync, and the rails / custody / controls that make a regulated flow possible. We ship all four as one product, on one architecture, with one team accountable end to end.
-
01
Consumer & operator apps
Web and mobile applications under your brand — onboarding, wallet, dApp browser, portfolio, admin console — with design tokens, PWA-quality behaviour and observability.
- Web + native mobile
- Design tokens per tenant
- Admin console
-
02
Smart contracts
Bespoke Solidity, Move or Rust contracts, or safe integrations with vetted third-party contracts under a change-managed deployment process (multi-sig owner, timelocks, rehearsed rollback).
- Solidity · Move · Rust
- Threat model + property tests
- Independent audit before mainnet
-
03
Off-chain services
Indexer, price oracles, event listeners, notification and job runners, plus signed APIs and SDKs so integrators and your product team can extend the platform.
- Indexer + event queue
- Signed REST + webhooks
- iOS + Android SDKs
-
04
Rails, custody & controls
Fiat rails through partner PSPs, MPC or HSM wallet custody, KYC/KYB and screening controls where a regulated flow applies — engineered against your ledger and reporting.
- Card, SEPA, on-chain ramps
- MPC or HSM custody
- KYC, screening, Travel Rule
Stack
What sits behind a Web3 product built by a blockchain development company
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. Custody depth: wallet and custody engineering. Rule mapping: compliance engineering.
| Layer | What we build |
|---|---|
| Product surface | Web, mobile and admin apps under your brand, driven by design tokens One product surface, no shared multi-tenant backend behind it. |
| Wallet & key material | MPC (threshold) or HSM signing across hot, warm and cold tiers — user- or venue-side depending on the product Keys are generated inside your trust boundary and never leave it. |
| Smart contracts & protocols | Bespoke contracts or integrations with vetted protocols; change-managed deployment with multi-sig and timelocks Every contract carries a written threat model, tests and an independent audit trail. |
| Chain coverage | Bitcoin, EVM chains (Ethereum, L2 rollups, side chains), Solana and other UTXO / account networks New chains land as plug-ins on one core, not a fork. |
| Off-chain services | Indexer, oracles, event queues, notification and job runners with observability On-chain state and off-chain state stay reconciled by design, not by luck. |
| Fiat rails & liquidity | Card, SEPA, open-banking and PSP integrations with quote-lock and settlement Adapters plug into one router with failover between partners. |
| Compliance controls | KYC/KYB where required, sanctions and wallet-risk screening, Travel Rule messaging, market-abuse rules where relevant Rules run inside the flow; every decision writes to the audit log. |
| Runtime & delivery | EU-hosted, CI/CD pipelines, dependency and licence scans, 24/7 on-call cover Your identity provider, your key custody, your data regions. |
Product path
How a Web3 product action crosses the platform
Every intent in the Web3 product — a swap, a token mint, a stake, a payout — goes through the same gates before it becomes an on-chain fact. Speed comes from tuning the pipeline, not from skipping a step or trusting the caller.
- 01
Intent
Real time
A user or integrator triggers a product action from the app, an API or a connected dApp.
- 02
Policy
Sub-second
Limits, allow-lists, role and session checks run before any funds or signatures move.
- 03
Screening
Sub-second
Sanctions and wallet-risk vendors return a verdict where regulated flows apply; the reason is stored.
- 04
Sign or call
Sub-second
The wallet signs, the contract call executes, or the off-chain service processes — under the same change-managed rules.
- 05
Broadcast
Chain-bound
Transactions go on chain; indexer reads confirm inclusion, status and any contract events.
- 06
Reconcile
Immediate
A double-entry write closes the loop; portfolio and reports refresh from the same event stream.
Delivery
How we deliver a Web3 product engineering services project
Five steps, in this order. Regulated Web3 work runs inside the product backlog — no separate compliance phase bolted on before launch, no big-bang release of an untested Web3 product.
- 01
Scoping
Weeks 1–2
We map users, chains, contracts, 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
Topology, contract design, wallet model, off-chain services and screening flow written down first. Regulatory constraints shape the design.
- 03
Build
Two-week sprints
App, contracts, indexer, custody and admin ship in slices. Each merge runs tests, static checks and a dependency scan.
- 04
Hardening
Before launch
Independent third-party audit for mainnet contracts, load work, failure drills, recovery rehearsal and a pen-test window.
- 05
Launch and run
Cutover + ongoing
Named engineers on 24/7 cover. Runbooks, dashboards, contract upgrade playbooks and the audit log are handed to your team on day one.
Engagement
Four ways to buy Web3 product engineering services
Same engineers, same standard. Only the commercial shape changes.
-
Fixed-scope build
A defined Web3 product at a fixed price and date. Best when chains, contracts and rails are settled.
-
Dedicated team
A standing squad with a lead. Best for long roadmaps and new chains or protocols each quarter.
-
Staff augmentation
Senior engineers inside your team. Best when you already own the plan and need Web3 depth.
-
CTO advisory
Architecture and buy-vs-build review before you commit. Best at the design stage.
Questions
FAQ: blockchain development company and Web3 services
Six answers up front on scope, generic-agency trade-offs, product shapes, contract security, compliance and support. Bring the rest to the call.
What do Web3 product engineering services from TrustChange actually deliver?
We engineer a bespoke, client-owned Web3 product end to end: consumer and operator apps, smart contracts, off-chain services (indexer, oracles, job runners), fiat rails, wallet and custody, and the compliance controls. Everything ships as source code in your repositories, with the IP assigned to you and app bundles signed under your own Apple and Google identifiers. There is no per-seat licence, no shared multi-tenant backend and no vendor gate between you and your users.
How is your blockchain development company and Web3 services offer different from a generic dev agency?
A generic agency ships a dApp; TrustChange ships a regulated-ready product. That means a standing EU squad with a named delivery lead, a change-managed smart-contract deployment process (multi-sig owner, timelocks, rehearsed rollback), MiCA / PSD2 / AML / GDPR engineered into delivery where the product touches regulated flows, and audit evidence produced on every release. A bespoke build takes longer up front, but you keep every line of code and every deployment decision.
Which product shapes and Web3 patterns do you build?
Tokens and tokenised assets, dApps and DeFi front-ends, wallets (custodial or non-custodial), NFT marketplaces, staking and delegation products, bridges and integrations with vetted protocols, plus back-office platforms that sit under them. If the product has a regulated flow (fiat ramp, custody, KYC-gated feature) we engineer the controls into the same product; if it's fully self-custody we ship the controls that apply and disclose the model to users transparently.
How do you handle smart-contract security and on-chain risk?
Contracts are written against a written threat model, reviewed internally, put through static and property-based testing, and sent to an independent third-party audit before mainnet deployment. Deployments run through a change-managed process with multi-sig ownership, timelocks on privileged actions and a rehearsed rollback path. Post-launch, an indexer and monitoring stack watches for anomalies and reconciles on-chain state against the off-chain ledger.
How are MiCA, PSD2, AML/Travel Rule and GDPR engineered into the Web3 product?
TrustChange is an engineering partner, not a law firm — your legal advisers and MLRO set the policy, we ship the controls and the evidence. That means KYC/KYB flows in onboarding where required, sanctions and wallet-risk screening before signing, Travel Rule data on crypto transfers, PSD2-aware fiat flows and GDPR-aware storage with data mapping and retention rules. Nothing about licences, opinions or supervisor approvals is claimed on your behalf.
Do you also run the Web3 product 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, contract upgrade 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 product engineering services
Bring the product shape, the chains, the contracts in scope, the licence context and the launch date. We come back with a squad shape, an architecture view and a costed plan for a Web3 product you own end to end. No demo theatre.