# Senior Software Engineer II, AI Developer Foundations

**Company:** [SimplePractice](https://hotfix.jobs/companies/simplepractice)
**Location:** Remote
**Role:** ML Engineering
**Salary:** $208k – $260k/yr
**Experience:** 7+ years
**Skills:** Ruby on Rails, LLMs, AWS, Terraform, Kubernetes, Docker, MySQL, Redis, sidekiq, ember.js, GitHub, Datadog
**Posted:** 2026-07-31

> Build and own AI-assisted engineering tools, conventions, context layers, and evaluation frameworks inside a large Rails monolith to scale AI usage across engineering, product, and design teams. Requires 7+ years production software experience with recent Rails and LLM-backed system expertise.

## Job Description

## Responsibilities
- Own the context layer agents read: rules files, docs conventions, grounding data, with CI and named owners keeping it current
- Publish the standards for how we prompt coding agents, how we supply context, and what a spec needs to contain before it's worth handing to an agent
- Define the review gates any AI-generated artifact clears before a human spends time on it, and get what reviewers catch flowing back into the conventions
- Take the prototypes running today and turn the ones that hold up into supported workflows that run for someone other than their author
- Evaluate harnesses, models and vendors against criteria and eval sets
- Work the product-to-engineering handoff with PMs, designers and EMs
- Teach. Documentation, worked examples, office hours, and time sitting with a squad while they work with the tools we build
- Help us draw the boundaries for where an agent runs unattended, where a human signs off, and where we don't use one at all

## Requirements
- BS/MS in Engineering, Computer Science, or related field, or equivalent experience
- 7+ years building production software and then maintaining it. You’ve shipped something, lived with the decisions, and found out whether a design decision held up
- Strong problem-solving and communication skills; comfortable in fast-paced, cross-functional environments
- Recent, direct Ruby on Rails experience in a large codebase
- Ability to read unfamiliar application code quickly and judge whether what an agent produced in it is any good
- LLM-backed systems you've shipped to users and kept running, past the point where better prompting stops helping
- Experience building context or memory handling, and writing evals
- Judgment about what belongs in code and what belongs in the model
- Track record evaluating tools with evidence
- Internal tools, platforms, conventions or workflows that other engineers chose to use
- CLI and harness-shaped software, and comfort connecting systems over APIs
- Strong writing. Much of this role is getting other people to work differently, which happens through docs and worked examples rather than announcements
- Comfort working outside engineering, explaining technical constraints to people who don't share your background and taking their pushback seriously

## Nice-to-Haves
- Agent harnesses, MCP servers, orchestration frameworks
- Healthcare or another HIPAA-regulated environment
- AWS, Terraform, Kubernetes, Docker
- Experience on a platform or infrastructure team where the customers were other engineers
- Having overbuilt a platform once before the workflows existed, and learning to spot the warning signs earlier

## Our Stack
Ruby on Rails monolith, Aurora MySQL, Redis, Sidekiq, Ember.js, AWS (EKS, Bedrock and more). Linear, GitHub, Semaphore, Datadog, LaunchDarkly.

## Benefits
- Medical, dental, vision, life & disability insurance
- 401(k) plan with company match
- Flexible Time Off (FTO), wellbeing days, paid holidays, and summer Fridays
- Mental health resources
- Paid parental leave & Backup Care
- Tuition reimbursement
- Employee Resource Groups (ERGs)

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**Apply:** https://hotfix.jobs/jobs/fe839a3a-ac68-4f70-b481-bebf399227dc
**Canonical:** https://hotfix.jobs/jobs/fe839a3a-ac68-4f70-b481-bebf399227dc