Staff Software Engineer - Experimentation

Stack

Responsibilities

• ▹Design and build the core primitives of the experimentation platform: assigning users to experiments, recording what someone actually saw, recognizing the same person across devices and between anonymous and signed-in states
• ▹Decide the long-term experimentation and feature flagging stack; evaluate and consolidate the current LaunchDarkly and Statsig architecture
• ▹Make AI part of the workflow: validating an experiment's setup before it starts and automatically catching broken experiments
• ▹Expand experimentation capabilities into market-based testing (whole geographic markets, long-term holdout groups)
• ▹Raise how well the whole company experiments: defaults, review, documentation and education
• ▹Gather needs from teams, sequence them into a roadmap and say no clearly, acting partly as technical product manager
• ▹Own assignment, exposure and the experiment data pipelines, working closely with Data Science and the teams owning event tracking and metric definitions

Requirements

• ▹Staff-level engineer whose impact is measured by what other teams can now do
• ▹Owned an experimentation or feature flagging stack end to end rather than only used one, accountable for the correctness of results
• ▹Built the parts that do not come out of the box: assignment that persists correctly, exposure that reflects what a user actually saw, identity resolved across sessions and devices, diagnostics that catch broken experiments early
• ▹Fluent enough in statistics to be a real partner to data scientists; able to tell a weak result from an invalid one
• ▹Debugged hard measurement bugs: uneven traffic splits, users in both arms, vanishing effects, identity breaking between anonymous and logged-in sessions
• ▹Built a program and not only a platform: measurably raised how an organization experiments through defaults, templates, review and teaching
• ▹Made and lived with a build versus buy call; can reason about vendor risk and warehouse-native versus hosted approaches
• ▹Landed a migration on teams that did not ask for one by making the new path easier than the old one rather than by mandate
• ▹Use AI as genuine leverage and have clear opinions on where it must not be trusted without a human
• ▹Driven technical direction beyond your own team through design documents, reviews and planning cycles; regularly mentor senior engineers
• ▹Willing to flex across the stack: backend services, front end rendering, CDN behavior and the data warehouse

Nice to have

• ▹Experience with multi-sided marketplaces, growth or search and ranking systems, or healthcare

Soft skills

What we offer

• ▹Base pay of $265,000-$331,000 depending on qualifications, experience and location; possible equity grant
• ▹Medical, dental and vision coverage
• ▹HSA / FSA
• ▹401K
• ▹Work-from-home stipend
• ▹Therapy reimbursement
• ▹16-week parental leave for eligible employees
• ▹Carrot Fertility annual reimbursement and membership
• ▹13 paid holidays plus a holiday break between December 25 and 31
• ▹Flexible PTO
• ▹Employee Assistance Program (EAP)
• ▹Training and professional development

About the company

Headway's mission is to build a mental healthcare system everyone can access. Over 75,000 providers and more than 1 million patients in the US use its software; it is a Series D company with $325M+ in funding.