Blockchain software · engineering partner
Blockchain software development services,
engineered as a system you own.
TrustChange delivers blockchain software development services for EU-facing crypto startups, licensed VASPs, PSPs, EMIs, neobanks and banks. A standing EU squad engineers chain and protocol integrations, smart contracts, wallets and custody, off-chain services and the product surface on top — as bespoke code under your brand, with the compliance controls and audit evidence your reviewer expects. Client-owned code, EU-hosted infrastructure, no SaaS licence.
- EU-based engineers
- MiCA-ready architecture
- AML & Travel Rule aware
- GDPR-aware storage
What "software services" means here
Blockchain software development services without the packaged-SaaS strings
Most searches for blockchain software development services surface either a generic dev shop with no digital-asset depth or a multi-tenant SaaS with a fixed feature set. We work the other way. TrustChange engineers chain adapters, contracts, wallets and off-chain services against your actual use case — under your brand, on your infrastructure, with the controls and evidence baked in. Digital-asset engineering is the core of what we do, not a bolt-on.
Deciding whether to buy, build or wrap? Start with CTO advisory. Adjacent shapes: blockchain development services, blockchain app development services, blockchain development outsourcing services and enterprise blockchain development services.
Service areas
Three service areas in every blockchain software development services engagement
Blockchain software is not one artefact. It is chain adapters and protocol integrations, contracts / wallets / custody, and the off-chain services that keep the on-chain side honest. We build the three together, on one plan, with one team accountable end to end.
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01
Chain & protocol integrations
Adapters into Bitcoin, EVM chains (Ethereum, L2 rollups, side chains), Solana and other UTXO / account networks — behind one canonical interface so the product does not depend on a specific chain library.
- Bitcoin · EVM · Solana
- Canonical adapter contract
- Reorg-aware indexer
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02
Contracts, wallets & custody
Bespoke Solidity / Move / Rust contracts, MPC or HSM signing across hot / warm / cold tiers and dApp / SDK integration — engineered against a written threat model and put through independent audit before mainnet.
- Solidity · Move · Rust
- MPC · HSM signing
- Independent audit before mainnet
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03
Off-chain services & controls
The pieces that keep on-chain honest: indexer, event queues, oracles, notifications, screening pipeline and the compliance evidence log that a reviewer will actually open.
- Indexer + event listeners
- Oracles + notifications
- Compliance evidence log
Stack
What sits behind bespoke blockchain software
Eight layers, one system. Every layer names an owner, a control and a piece of audit evidence — nothing is left implied under the "blockchain" label.
Delivery patterns and evidence: how we deliver. Wider platform view: fintech infrastructure. Wallet depth: wallet and custody engineering.
| Layer | What we build |
|---|---|
| Product surface | Web, mobile and admin apps under your brand, driven by design tokens per tenant One product surface, no shared multi-tenant backend behind it. |
| 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. |
| Smart contracts | Bespoke or integrated contracts under a change-managed deployment process with multi-sig ownership and timelocks on privileged actions Every contract carries a written threat model, tests and an independent audit trail. |
| Wallet & key material | MPC (threshold) or HSM-backed signing across hot, warm and cold tiers Keys are generated inside your trust boundary and never leave it. |
| Off-chain services | Indexer, event listeners, price oracles, notifications and job queues 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, 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. |
| Delivery & DevSecOps | EU-hosted CI/CD, observability, dependency and licence scans, 24/7 on-call cover Your identity provider, your key custody, your data regions. |
Transaction path
How a transaction crosses the software
Every transfer, swap or contract call goes through the same gates before a key is touched. Speed comes from tuning the pipeline, not from skipping a step or trusting the caller.
- 01
Request
Real time
A user or system triggers a transfer, swap or contract call from the product surface or an API caller.
- 02
Policy
Sub-second
Limits, allow-lists, quorum thresholds and role checks run before any key is touched.
- 03
Screening
Sub-second
Sanctions and wallet-risk vendors return a verdict; the reason is stored with the request.
- 04
Sign
Sub-second
MPC or HSM signing runs inside your trust boundary; keys never leave it.
- 05
Broadcast
Chain-bound
The signed transaction goes on chain; on-chain reads confirm inclusion, revert or replacement.
- 06
Ledger
Immediate
A double-entry write closes the loop; every step is stored with rule version and vendor id in the audit log.
Delivery
How we deliver blockchain software development services
Five steps, in this order. Regulated crypto work runs inside the product backlog — no separate compliance phase bolted on before launch, no big-bang release of an untested contract or bridge.
- 01
Scoping
Weeks 1–2
We map chains, contracts, wallets, 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, key handling, off-chain services and screening flow written down first. Regulatory constraints shape the design.
- 03
Build
Two-week sprints
Contracts, wallet, indexer, product surface 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 and a pen-test window. Recovery is rehearsed with your staff.
- 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 blockchain software development services
Same engineers, same standard. Only the commercial shape changes.
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Fixed-scope build
A defined blockchain platform at a fixed price and date. Best when chains, contracts and rails are settled.
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Dedicated team
A standing squad with a lead. Best for long roadmaps and new chains each quarter.
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Staff augmentation
Senior engineers inside your team. Best when you already own the plan and need blockchain depth.
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CTO advisory
Architecture and buy-vs-build review before you commit. Best at the design stage.
Questions
FAQ: blockchain software development services
Six answers up front on scope, off-the-shelf trade-offs, chains & contracts, security, compliance and support. Bring the rest to the call.
What do blockchain software development services from TrustChange actually cover?
We engineer a bespoke, client-owned blockchain build end to end: chain and protocol integrations, smart contracts, wallets and custody, off-chain services (indexer, oracles, jobs), fiat rails, compliance controls and the product surface on top. Work lands in your repositories under your Git history, with the IP assigned to you. There is no per-seat licence, no shared multi-tenant backend and no vendor gate between you and your users.
How are your blockchain software development services different from an off-the-shelf provider?
Off-the-shelf providers bundle a generic product with a licence fee, and the code lives inside the vendor's platform. TrustChange engineers the chain adapters, the contracts, the indexer, the wallet and the controls against your actual use case — chains, licence context, audit expectations and roadmap. A bespoke build takes longer up front, but you keep every line of code, every deployment key and every control decision.
Which chains, contract languages and off-chain pieces do you cover?
Bitcoin, EVM chains (Ethereum, L2 rollups, side chains), Solana and other account or UTXO networks land as plug-ins on one core. Contracts are written bespoke in Solidity, Move or Rust where the product needs them, or the app integrates with vetted third-party contracts under a change-managed deployment process (multi-sig owner, timelocks on privileged actions, rehearsed rollback). Off-chain: indexer, event queues, price oracles, notifications, screening pipeline and admin consoles.
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 in?
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 in onboarding, 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 platform 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 and roadmap work, or as CTO advisory on architectural calls.
Book a discovery call for blockchain software development services
Bring the chain list, the contract scope, the licence context, the target markets and the launch date. We come back with a squad shape, an architecture view and a costed plan for a platform you own end to end. No demo theatre.