Staff Software Engineer, Fraud

Replit

Staff Software Engineer building robust security solutions for Replit's AI-driven platform against fraud. Leading the design and implementation of abuse detection and prevention systems.

Posted 5/27/2026full-timeFoster City • California • 🇺🇸 United StatesLead💰 $250,000 - $315,000 per yearWebsite

Tech Stack

Tools & technologies

BigQueryPythonSQLTypeScript

About the role

Key responsibilities & impact

Design and implement LLM guardrails that detect abuse scenarios in AI-generated code and agent interactions
Build AI-powered detection systems that use LLMs to identify malicious patterns, classify threats, and automate response decisions
Build and operate abuse detection systems that identify phishing, cryptomining, account takeover, and financial fraud across millions of daily user actions
Design automated response mechanisms that enforce platform policies without manual intervention
Own the full abuse response lifecycle: detection, investigation, enforcement, and handling appeals alongside Support and Legal
Analyze attack patterns using BigQuery and Hex, turning investigation findings into new detection rules
Maintain and extend internal detection tools (Slurper, Netwatch) that continuously monitor user activity
Integrate and tune security scanners (SAST, SCA) in CI pipelines with tight performance SLAs
Track abuse trends, measure detection effectiveness, and adapt defenses as attack patterns evolve

Requirements

What you’ll need

8+ years of experience in security engineering, anti-abuse, trust & safety, or fraud detection
Strong programming skills in Python and/or TypeScript for building detection systems and automation
Experience with SQL and data analysis at scale (BigQuery, Snowflake, or similar)
Experience building or fine-tuning ML/LLM-based classifiers for security or abuse detection
Familiarity with prompt injection, jailbreaking, and other LLM-specific attack vectors
Ability to investigate complex abuse patterns and translate findings into automated defenses
Familiarity with common attack patterns: phishing infrastructure, account takeover, credential stuffing, resource abuse
Clear communication skills for working across Security, Support, Legal, and Engineering teams.

Benefits

Comp & perks

Competitive Salary & Equity
401(k) Program with a 4% match (*US Only*)
Health, Dental, Vision and Life Insurance
Short Term and Long Term Disability
Paid Parental, Medical, Caregiver Leave
Flexible Time Off (FTO) + Holidays
Commuter Benefits (*In-Office Only*)
Monthly Wellness Stipend
Autonomous Work Environment
In Office Set-Up Reimbursement (*In-Office Only*)
Quarterly Team Gatherings
In Office Amenities (*In-Office Only*)

ATS Keywords

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Applicant Tracking System Keywords

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Hard Skills & Tools

PythonTypeScriptSQLBigQuerydata analysisML classifiersLLM-based classifiersautomated defensessecurity scannersCI pipelines

Soft Skills

clear communicationinvestigationproblem-solvingcollaborationadaptability