Fixed scope · Fixed deliverables · Remote B2B

Custody reviews that leave an evidence trail.

I work with custodians, exchanges, stablecoin issuers, tokenization platforms and banks that hold or move digital assets for clients. We agree the scope, deliverables and price in writing before work begins.

Read-only by default. No access to keys or client assets. Everything learned about your systems remains under NDA.

Describe your setup Read field notes

Engagements

Custody architecture review2 weeks · fixed fee: I review key management and signing, deposit detection, transaction lifecycle, reorg handling, ledger integrity and client-asset segregation. You receive a written report with severity-ranked findings, sequenced remediations and a walkthrough.
Evidence-readiness assessment1–2 weeks · fixed fee: I assess how internal positions reconcile against chain state and map the gaps against safeguarding, record-keeping and recovery expectations. You receive a reconciliation policy and a reproducible evidence format an auditor can use.
Fractional custody engineeringRetainer · limited capacity: Ongoing architecture decisions, code review of signing and ledger paths, incident support and build-vs-buy guidance for teams that need senior custody judgment without a full-time hire. I take one retainer engagement at a time.

Fit

Good fit

A live or inherited system holds client assets.
An audit, launch, incident or architecture decision created urgency.
You want findings your engineers can verify and act on.

Not a fit

Speculative token promotion or anonymous launch support.
An open-ended build with no owner, scope or decision deadline.
Any engagement requiring custody of production keys or funds.

How it works

1. Scope: A 30-minute call establishes the system boundary and why the work matters now. You then receive a one-page scope with deliverables, access needs and fixed price.
2. Evidence: I work from read-only code, architecture documentation and operating evidence. Assumptions and unavailable evidence are explicit rather than silently filled in.
3. Handoff: The report, policy and evidence formats are yours. They are written so an engineer, auditor or regulator can use them without me in the room.

Start with the problem, not a sales deck.

Email contact@maciejlewandowski.dev with a short description of your setup and what prompted the request, or reach me on LinkedIn. I reply within one business day.