I build and scale full-stack products with production-grade infrastructure

I ship product from frontend UX to backend execution, while building the infra and SDK foundations that keep it reliable at scale. I am targeting founding-engineer opportunities where this end-to-end ownership is core.

Product-facing frontend Backend execution systems Cross-chain infrastructure SDK ownership

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Live activity

joepegler:

Status

Cork, Ireland. GMT. Open to senior full-stack roles and founding-engineer opportunities.

Track record

End-to-end ownership across product and platform, with measurable outcomes.

In-house account abstraction bundler

Address #1 of 15 on Etherscan

Scale: 5k to 7k swaps per day
Performance: ~30% / ~20% faster execution than Zerodev / Pimlico respectively
Reliability: ~103% success rate compared to ZD/Pimlico
Cost: Roughly 20 to 40% of execution costs (no middlemen)

Work

Built retry and fallback execution model
Debugged simulation vs execution mismatches
Identified nonce race conditions and wallet contention
Investigated RPC inconsistencies (e.g. Base chain lag)
Handles slippage, RPC lag, retries, simulation mismatches in production

Bulletproof ERC-2612 permit system

Full write-up

Reliability: Zero user-facing permit failures on supported tokens
Coverage: USDC, GHO, Morpho, OpenZeppelin, Solmate and others across 5+ chains
False positives caught: stETH, bsdETH, Morpho vaults and other tokens that pass heuristic checks but revert on permit()

Work

Two-pass detection: heuristic multicall probing, then ephemeral-key on-chain simulation
Stub-and-swap runtime pattern so users browse quotes without wallet popups
Consistent version() fallback logic across detection, simulation, and SDK signing
Self-healing batch pipeline with chunk-level error isolation

Statecraft deterministic test SDK

Project site

Problem: Ethereum integration tests often hide setup order and drift into flaky helper stacks
Approach: Typed scenario fixtures with explicit setup order and pinned chain state
Outcome: Clearer integration tests with deterministic, reproducible setup as suites grow

Work

Designed scenario pipeline primitives for TypeScript and viem-based tests
Implemented chain runtime fixtures for local and forked workflows
Documented adoption path from hook-heavy tests to explicit fixture composition
Shipped as open source with docs and runnable examples

Impact

Ownership from product UI to infrastructure. Cork, Ireland (GMT).

Shipped full-stack trading and execution flows used in production, from product UI to backend transaction routing.
In-house bundler in production with retries, simulation, and multi-chain routes (LiFi, Jupiter, 1inch, Odos, LayerZero).
Led TypeScript SDK for smart accounts and multi-chain execution at biconomy. Gasless flows, EIP-712/1271, passkeys.
Built Statecraft, an open-source SDK for deterministic Ethereum integration testing with explicit TypeScript scenario fixtures.
Main dApp developer at enso, delivering decentralized trades and actions on Ethereum with a robust backend.
Simulation, retry logic, typed clients, and DX-focused docs that reduced production friction.
CI/CD and release discipline for critical surfaces (coinflex, enso, defi.app).

What I build

Full-stack and platform engineering with strong end-to-end ownership.

Product-facing frontend

High-signal interfaces for complex flows. Clear UX for quoting, signing, and execution states.

Backend & platform systems

APIs and execution services with retries, simulation, and reliability under partial failures.

Developer tooling & SDKs

Typed clients, clear errors, and docs that match behaviour so teams integrate quickly.

Infra depth as a differentiator

Account abstraction and cross-chain execution across EVM and Solana, with production observability.

Systems Built

Production product and platform systems owned end to end.

defi.app

Full-Stack & Infrastructure Engineer · Apr 2025 – Present

Owned architecture Shipped prod infra Led SDK

Problem: Users needed fast, reliable multi-chain swap and bridge flows with sponsorship, without a brittle UX.

System: End-to-end delivery across product and platform: in-house account abstraction bundler with retries and simulation, plus TypeScript SDK surfaces that power routing and execution. Sourcify/custom ABIs. Routes: LiFi, Jupiter, 1inch, Odos, Mayan, LayerZero. Smart accounts (ZeroDev/Kernel), RouteClient, ExecutionManager. Action providers: Aave, Morpho, Hyperliquid, Relay. EVM and Solana simulation and sponsorship.

Result: 5k to 7k swaps/day and ~95% success rate, with 20 to 40% faster execution than Zerodev and a meaningful share of execution traffic. Slippage, state overrides, and Jito handled in production.

Bundler on Etherscan View full resume

biconomy

Lead Full-Stack SDK Engineer · Nov 2023 – Apr 2025

Led SDK direction Shipped prod infra

Problem: Teams needed one reliable way to ship smart-account product flows across chains with modern signing and strong DX.

System: TypeScript SDK for smart accounts and multi-chain execution, designed for both app integration and backend orchestration. Modular viem-based client, Safe support, EIP-712/1271 signing (P-256/passkeys), quote/sign/execute flows, and session permissions. Gas and latency optimisation via bundler integration and concurrency. Composable batching, typed errors, docs. CI: Vitest, Bun, GitHub Actions, Codecov; automated funding.

Result: Production SDK powering gasless and account-abstracted user journeys with clear DX and maintainable test coverage.

View full resume

Statecraft

Open-source side project · 2026 – Present

Owned architecture Shipped SDK Wrote docs

Problem: Full-stack teams lost velocity when integration tests depended on hidden hooks and ad hoc helpers.

System: A TypeScript-first SDK that composes explicit scenario fixtures (chain, fork, funded wallet, token balance) into one deterministic test pipeline for viem-based projects.

Result: A clearer path to deterministic integration tests, faster onboarding, and parallel-friendly suite design without replacing existing test runners.

Project site GitHub

enso

Full-Stack Developer · Jun 2021 – Oct 2023

Owned architecture Led product surface

Problem: Build and scale a client-facing Ethereum dApp while keeping backend matching and execution reliable.

System: Owned both main dApp experience and backend (NestJS), including intents and solver flows for matching and executing decentralized trades and actions.

Result: Unified full-stack product serving users with reliable intents/solvers execution.

View full resume

coinflex

Head of UI/UX · Jul 2019 – Jun 2021

Directed product Shipped prod infra

Problem: Deliver a reliable, scalable trading product with a repeatable release process for a critical surface.

System: Led trading interface and core features end to end, with code reviews and fully automated CI/CD. Drove code stability and component reusability across the product.

Result: Production-grade trading UI with an automated lifecycle and higher confidence in feature delivery.

View full resume

Recommendations

Selected feedback from people I worked with directly on core infrastructure, SDK ownership, and production delivery.

"Joe owned our SDK, the core infrastructure layer powering $100M+ in daily trading volume across swaps, on-ramps, and perpetuals. He mapped external specs to our codebase faster than anyone and caught edge cases that would have broken production."

Dan Greer

Founder & CEO, Defi App · Managed Joe directly

"Joe owned the bundler and transaction pipeline end to end and led our SDK and cross-chain execution systems from early ideas to solid production releases. He brings structure to ambiguous problems and ships reliably."

Ajdin Kahrovic

Blockchain Engineer, Defi.app · Managed Joe directly

View all recommendations on LinkedIn

Contact

Full-stack product delivery with infrastructure depth: transaction flow and system design. Open to senior full-stack roles and founding-engineer opportunities. Cork, Ireland (GMT). Reply within 24 to 48 hours.

Get in touch View technical resume

pegler.web.services@gmail.com GitHub LinkedIn Twitter