Senior Software Engineer, Custody

Location:Remote-friendly globally. Time-zone band UTC-1 to UTC+5 (meaningful Saudi hours overlap). Optional relocation to Riyadh.
Reports to:Custody Platform Lead.
Type:Full-time. Individual Contributor.

About us:
The company is the digital-asset custody and infrastructure platform for the GCC. We hold institutional crypto safely, settle transactions across chains, and expose all of that as a developer API and a regulated-grade institutional console.

The role:
You are a senior backend engineer with a custody and key-management background. You will be a foundational engineer on the company's custody platform, reporting to the Custody Platform Lead.

You will:
Ship production custody codeacross signing service, key management, chain integrations, and the transaction pipeline.
Own a chain or a subsystem.Within 3 months you should own a meaningful surface end-to-end (a chain integration, a signing-service component, a key-rotation flow).
Pair with the Custody Platform Lead and our in-house cryptographyfunction on threshold signing, share generation, and key recovery flows.
Write post-mortemswhen things break. We treat these as architecture-improvement opportunities, not blame exercises.
Integrate new chains.Bitcoin, Ethereum and L2s, Solana, and an active onboarding queue.
Engage in async written communication.Spec docs, PR descriptions, async design reviews.

Must-haves:
5-plus years of backend engineering, with thelast 2-plus years on a custody platform or a key management system at a regulated entity. General fintech does not substitute.

Hands-on with at least one of:
HSM lifecycle (CloudHSM, YubiHSM, Ledger Vault, similar).
MPC / TSS (Fireblocks-style, Sepior, ZenGo, Curv-style).
Threshold signing schemes (GG18, GG20, FROST, CGGMP21, CMP).

Production experience with one or more of:
Bitcoin (UTXO model, PSBT).
Ethereum (EIP-712, EIP-1559, account abstraction).
At least one non-EVM Layer 1 (Solana, Sui, Cosmos SDK chain, similar).

Reads Solidity, Move, or Rustwell enough to integrate with new chains without hand-holding.
Strong async written communication.Your PR threads, design docs, and intro reply are themselves a signal.
English fluency.

Nice-to-haves:
Experience with travel-rule / FATF compliance integrations (Notabene, Sumsub, TRP, IVMS101).
Authored or contributed to an EIP, BIP, or chain RFC.
Audit-contest finalist on Code4rena, Sherlock, or Cantina.
Familiarity with regulated-financial controls: dual-control, four-eyes, M-of-N approvals, SOC 2 evidence collection.

This is not the right role if:
Only frontend / dApp experience, no backend custody or key-management depth.
"Crypto trader who codes." Algorithmic trading without custody experience.
Anyone whose entire blockchain experience is a single hackathon, bootcamp, or DeFi side project.
Currently subject to a non-compete blocking digital-asset custody for more than 6 months.

Stack:
Backend:Go primary. Some Rust, some TypeScript. Aurora Postgres and ClickHouse. Temporal for orchestration.
Cryptography:in-house MPC stack (TSS-based), HSM integrations, multi-chain signing service.
Chains:Bitcoin, Ethereum and L2s, Solana, active onboarding queue.
Infra:AWS, Kubernetes, GitHub Actions CI, Terraform.
Security posture:SOC 2 Type II in motion, SAMA-aligned, intent toward ISO 27001 and dual-control workflows.

Location, visa, relocation:
Location:Riyadh, open to Remote Opportunity.
Time-zone band:UTC-1 to UTC+5 for meaningful Saudi-hours overlap.
Relocation (optional):if the candidate elects to relocate to Riyadh, we’ll support sponsorship.
Tax / payroll:KSA payroll for relocates. Contractor or Employer-of-Record for remote-international.