Daniel Peach

Senior Backend / API Engineer

Brownsburg, IN dpeaches96@gmail.com linkedin.com/in/djpeach github.com/djpeach

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Summary

Senior software engineer with 9+ years building backend APIs, services, and frontends, including large-scale financial systems in fintech. At Greenlight, co-owned the Chase banking integration including money movement, ledgers, accounts, authorizations, and remediation pipelines. At Disco, led API-first platform design, industry-standard live/sandbox API-key model, reduced latency, and enabled serving external partners at scale. Thrives on autonomy and ownership and works comfortably across languages and stacks.

Experience

Senior Software Engineer, Disco Network

Feb 2025 - Present
  • Led the API-first, spec-driven design and ground-up build of a high-throughput ad-serving API (FastAPI) and server-to-server event pipeline. The API spec was the driving force of winning the bid for ad-serving with the company's two largest external partners, Gopuff and Mindbody.
  • Drove p95 latency on the serving path from 1.5s to 120ms (about 12x) and p50 to 35ms via custom logging configuration, SQL and hot-path optimization, and runtime caching.
  • Re-architected API key management to an industry-standard model using live and sandbox modes with publishable/secret key pairs, based largely on Stripe's pk/sk/rk pattern.
  • Led DiscoBeat, a platform for onboarding and serving partner channels at scale, with channel-management APIs and a dynamic link-level system applying cascading filters and payout configurations.
  • Refactored the experimentation framework, then owned a six-month portfolio of A/B experiments end to end including design, execution, and reporting.
  • Championed a shared Python library across services and modernized engineering tooling (e.g. pipenv to uv, introduced typing with pydantic and type hints).

Senior Software Engineer, Greenlight Financial Technology

2021 - 2025
  • Co-owned Greenlight's Chase banking integration (Chase First Banking) as one of just two engineers, designing and operating the core money-movement systems under high autonomy.
  • Shipped new transaction types and banking features for Chase, including a student-graduation flow and a rolling-balance feature built on ledger and spending data.
  • Built ledger transaction remediation pipelines that detected and corrected discrepancies, keeping customer balances accurate and reconciled at scale.
  • Built authorization-expiration handling for card transactions and automated balancing/reconciliation with Chase, reducing customer call-ins (Java).
  • Scripted incident remediation and large-scale data migrations affecting millions of customers.
  • Cut CI runtime and cost by 90%+ (Node).

Full-Stack Software Engineer, Genesys

2019 - 2021
  • Built a reusable React component library for call-center and help-desk clients, replacing fragile in-house components with robust standard libraries.
  • Integrated Jenkins with the in-house deployment network, speeding deployments by 20-50%.

Full-Stack Software Engineer, Angie's List

2018 - 2019
  • Built shared iOS code libraries across two apps, migrated the codebase from Objective-C to Swift, and increased search content by 30% via a backend integration (Scala).

Web Developer, Coles Marketing

2017 - 2018
  • Automated data entry and web scraping with Python, built custom WordPress templates and plugins (PHP), and led adoption of Git-based version control.

Education

B.S., Computer Science

Indiana University-Purdue University Indianapolis (IUPUI)

2017 - 2021

Skills

Languages: Python, Java, Kotlin, JavaScript, TypeScript, Scala, SQL

Backend & APIs: REST/spec-driven API design (OpenAPI), FastAPI, Django, Spring Boot, Node.js, Pydantic

Infrastructure & Data: AWS, Docker, Kubernetes, Redis, PostgreSQL, Snowflake

Domains & Practices: Large-scale transaction & ledger systems, incident remediation, CI/CD, A/B experimentation, automated testing (pytest)