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Senior Contract Role

Wallet Advisor

Neurabuild is recruiting a senior contractor to advise (and possibly take on the build of) a custodial mobile wallet for a fintech consortium operating in Southern Africa. The wallet sits on top of a Polygon-based stablecoin and will plug into a regulated SA crypto payments processor's retail rails for cross-border merchant payments at major South African retailers.

Engagement

Contract — 6 to 8 weeks

Location

Remote, SA-based preferred

Rate

Day rate or hourly

Start

Immediate

The Project

The client has an 8-person dev team building the wallet from scratch — a mix of recent computer science graduates and current students. They are motivated and have shipped a closed-loop campus payment system, but they have not built a production custodial wallet before.

Note

Portuguese speaker — The dev team works primarily in Portuguese. Candidates who can communicate with the team in their own language will be significantly more effective. This is a strong preference, not strictly required.

What you'll do

  • —Architectural guidance on a custodial mobile wallet (Android-first, likely React Native or Flutter)
  • —Reviewing and steering: KYC/KYB integration, custodial key management (HSM/MPC), transaction ledger design, mint/burn flow with idempotency, FX engine, security model
  • —Code review and PR-level feedback for the team
  • —Pre-launch security readiness so the wallet passes a third-party integration review
  • —Coordinating with the broader project: a Polygon stablecoin (smart contract deployed), reserve account at a regional bank, and exchange integration on the SA side
  • —Helping the team prepare for a third-party smart contract audit (recommending firms, scoping)

What we're looking for

  • ▸Built or led a custodial wallet, fintech app, or payments product in production
  • ▸Comfortable with Polygon / ERC-20 / multi-sig contracts, even if you don't write Solidity yourself
  • ▸Have shipped code that handled real money at real volume
  • ▸Can coach a junior team without doing the work for them — but can also pick up a keyboard if needed

Bonus: Portuguese language. African fintech experience. Mobile money rails. Stablecoin work.

Practicalities

  • —Remote, SA-based preferred. The dev team is offshore in the region; the SA integration partner is in the Western Cape. One or two trips abroad are likely.
  • —Contract — day rate or hourly, open to either depending on shape
  • —Starts roughly 6–8 weeks of advisory; potential to extend into a full build contract
  • —Client is pushing for a working demo by end of May 2026, so this moves quickly
  • —Full client and counterparty disclosure under NDA before anything is committed

DM on ZATech or email careers@neurabuild.com with a short note on relevant past work (links over CV), your rate, and your level of Portuguese if any.

Happy to chat to anyone curious before committing. Forwards welcome — if you know a Portuguese-speaking senior dev who'd fit, please send them our way.