Solidity contracts (EVM)
ERC-20 / 721 / 1155 / 4626 / 6909, custom DeFi primitives, governance tooling, multi-sig integration. Audited deliverables.
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Senior engineering · Solidity / Smart contracts
Senior Solidity / Smart contracts engineering for production systems.
Production smart-contract engineering — Solidity, Foundry / Hardhat, audited deliverables, gas-optimized, upgrade-aware, and the operational discipline that distinguishes shipped contracts from GitHub demos.
- In production
- 2020+
- Senior bench
- 12+ G6/G9 engineers
- Floor
- G6+ on client work
- Engagement
- Outcome-led, not hourly
Why senior, not contractor
Solidity / Smart contracts in production is a different problem than Solidity / Smart contracts on a laptop.
Most smart-contract code shipped to mainnet today wouldn't survive a serious audit — unbounded loops, missing access controls, reentrancy without ReentrancyGuard, upgrade patterns no one can reason about. Prosigns ships smart contracts as production engineering: Foundry-led test discipline (fuzz, invariant, fork tests), gas optimization measured against benchmarks, upgrade patterns with explicit access controls, and audits scoped against the contracts that actually matter.
Senior floor
G6+ minimum
Bench depth
12+ G6/G9 engineers
In production
2020+
Engagement
Outcome-led SOW
Where Solidity / Smart contracts ships
6 sub-areas, grounded in shipped engagements.
Specific applications of Solidity / Smart contracts we’ve built and operate. Every example below maps to a real engagement, not a bullet on a stack-card.
01 02 Test discipline (Foundry)
Fuzz tests, invariant tests, fork tests against mainnet state, gas snapshots in CI, coverage targets > 95% on the contracts that matter.
03 Upgrade patterns
OpenZeppelin Transparent / UUPS / Beacon proxies, Diamond pattern (EIP-2535) where complexity warrants. Storage layout discipline.
04 Layer-2 + cross-chain
Arbitrum, Optimism, Base, Polygon zkEVM. LayerZero / Wormhole / Axelar for cross-chain messaging. Bridge security review.
05 Move (Aptos / Sui)
Move modules for Aptos and Sui with proper resource-typing, capability patterns, and the security guarantees Move was designed for.
06 Pre-audit hardening
Slither, Mythril, Echidna, Halmos for symbolic execution. Pre-audit cleanup against the audit firm's checklist before billable hours start.
Stack depth
The Solidity / Smart contracts ecosystem, owned.
Frameworks, libraries, and runtime tools the bench has shipped in production. Not a CV-skim — a working depth.
Toolchain
- Foundry
- Hardhat
- Forge
- Anvil
- Cast
Standards + libraries
- OpenZeppelin
- Solmate
- Solady
- ds-test
- PRBMath
Static analysis + security
- Slither
- Mythril
- Echidna
- Halmos
- Manticore
L2 + interop
- Arbitrum
- Optimism
- Base
- Polygon zkEVM
- LayerZero
Frontend + indexing
- wagmi
- viem
- Ethers.js v6
- The Graph
- Subsquid
Engagement models
Three ways to engage Solidity / Smart contracts engineers.
We don’t bill hourly contractors. Engagements run against outcomes — choose the shape that matches the work.
See engagement models- 01
Fixed-scope
Defined deliverable, fixed price
When the deliverable is clear and the scope is bounded — an MVP, a migration, a discrete platform build. Senior engineering against a written outcome, not against a body count.
- 02
Embedded squad
Senior product team, ongoing
When the work is product-shaped and the cadence is continuous. A senior pod (engineering + design + PM as needed) embedded into your team, with the practice lead co-piloting from HELM.
- 03
Managed services
Steady-state operations
When the system is running and needs ongoing engineering ownership — operations, SLO defense, release management, security and compliance evidence. Monthly retainer against a published SLA.
Selected work
Solidity / Smart contracts engineering that shipped.
DeFi
Lending-market smart contracts for a regulated DeFi protocol — Foundry-tested, Trail of Bits-audited.
Zeropost-audit findingsERC-4626 vault contracts with custom liquidation logic, UUPS-upgradeable with role-based access. Foundry fuzz + invariant suite at 96% coverage. Cleared a Trail of Bits audit with no major or critical findings.
Duration · 5 months
Brief us
Reply < 4 business hoursHave a Solidity / Smart contracts workload? Send a brief.
Five fields. Goes straight to the practice lead — not an SDR. We’ll reply with a senior engineer’s read on fit, scope, and the engagement model that suits the work.
FAQ
Questions buyers ask.
Everything below also appears in the proposal and the SOW — no surprises after signing.
Do you handle the audit process?
We pre-harden against the audit firm's checklist before billable hours start, coordinate the audit engagement, and remediate findings with regression-tested fixes. We’ve worked with Trail of Bits, OpenZeppelin, Spearbit, Code4rena, and Cantina across various engagements. We’re not auditors ourselves and we don’t pretend to be.
Foundry or Hardhat?
Foundry as default — faster, better fuzz / invariant testing, native Solidity testing. Hardhat where the customer's existing toolchain or specific plugin ecosystem demands it. We ship both.
Is this staff-aug, or is it engineering-led delivery?
Engineering-led delivery. We don't bill hourly contractors against your JIRA board. Every engagement runs against a defined outcome with a senior engineer accountable from kickoff to operating cutover. If you genuinely need staff-aug — discrete bodies, your management, hourly rates — we'll be honest and route you to a partner that fits.
What seniority floor are we talking about?
G6 minimum (six-plus years in their craft) on every billable hour. Department leads are G9 or G10. We don't flex juniors onto the bench mid-sprint, we don't subcontract to delivery centers, and we don't dilute senior rates with mixed staffing. The bench in the proposal is the bench in production.
How does pricing work?
Three engagement models published at /engagement-models/. Fixed-scope for defined deliverables, embedded squads for ongoing product work, managed services for steady-state operations. Rates depend on seniority, engagement length, and region. Discovery + scoping conversation is free; SOWs are written against deliverables, not bodies.
Where are your engineers based?
Senior-only across Dallas, Doha, Lahore, and Islamabad. We staff against the engagement's needs (timezone, language, regulatory frame), not against arbitrary regional preferences. Most engagements run with a US/EU-aligned core and a follow-the-sun extended bench when the workload warrants it.
Will the engineers I see in the proposal be the engineers shipping the work?
Yes. We name the engineers in the SOW, attach their profiles, and they're on the kickoff. We don't bait-and-switch with senior reviewers and junior execution. If a named engineer needs to roll off the engagement (rare), we surface a replacement from the same seniority tier with explicit handoff.
Talk to a Solidity / Smart contracts lead
Senior Solidity / Smart contracts engineering, accountable from kickoff.
Bring the workload — we’ll bring a senior engineer plus the practice lead most relevant to the work. 30 minutes, no obligation, no junior reps.