Time since we first saw it
Day 213
Up longer than most. Similar jobs usually come down between day 4 and day 77.
From 51 similar postings that came down. Coming down is not always a hire.
Senior AI/ML engineer
Reads like an AI Engineer role: building products on existing AI models.
- Pay
GBP 120,000–180,000/year — pay source
Annual Salary Range (ranges may vary based on skills and experience) £120,000—£180,000 GBP How we work
Read the full posting- Work setting
- Not stated
- Employment
- Not stated
What you’ll work on
Full postingBuild and ship LLM-powered product features in the app
Reduce AI response latency through streaming and pregeneration
Iterate on prompt design and model behavior for safe, high-quality output
Help run A/B tests for model and prompt changes with evaluation gates
Contribute to synthetic Q&A generation and evaluation test sets
From the employer’s posting
build and ship LLM-powered product features
reduce perceived and actual response latency through streaming, pregeneration, and inference-time tradeoffs
iterate on prompt design and calibration
help enable A/B testing for model and prompt changes, using evaluation gates to ship safely and measure impact
contribute to synthetic Q&A generation, golden test sets, and evaluation dataset design
Posting record
Report an errorOpen 7 monthsWe first saw this posting 213 days ago and it is still up. Roles open this long are often slow to fill or kept open to collect applications.
- Status in our records
- Live
- First seen by us
- Apr 14, 2026213 days ago
- Recorded sightings
- 183
- Last seen by us
- Nov 13, 2026
These dates show when we found the posting. Check the employer’s website to confirm it is still accepting applications.
How this job compares
Flo Health is hiring
2 open jobs
Open jobs by the week we first saw them, last 12 weeks.
Hiring recordSee how this role fits your experience
Add your resume and we’ll mark which of these tools you already use, and point out anything in the posting that could rule you out.
- Python
- AWS
- Databricks
- Delta Lake
- Terraform
Where the posting names them
- experience with at least one of: prompt engineering, LLM evaluation, fine-tuning, or model serving - strong Python, and comfort working with APIs/SDKs that wrap LLM calls, prompt templates, and structured outputs - product sensibility: a track record of shipping user-facing features, with attention to latency, tone, and quality of AI output as experienced by end users
The job We are looking for a Senior AI Engineer with strong LLM and product engineering experience to join our AI Platform team and help ship the AI-driven features across our app — including personalized in-app content recommendations, conversational AI-powered insights, and AI-generated mobile push notifications. You will focus on the product-facing behavior of our GenAI features (relevance, quality, latency, and safety), using the platform’s judges, fine-tuning pipelines, and evaluation tools, and contributing to infrastructure work (Databricks, AWS, Terraform) as initiatives require it. What you’ll do
- Data and evaluation: contribute to synthetic Q&A generation, golden test sets, and evaluation dataset design that supports the features you’re building - Infrastructure: contribute to Databricks, AWS (EKS), Terraform, or CI/CD work as initiatives require it - Cross-functional impact: collaborate with Product, Security, Analytics, and Medical teams, and engage with technology partners (Databricks, Google, OpenAI, Anthropic, AWS) on pre-release capabilities relevant to your features
- Infrastructure: contribute to Databricks, AWS (EKS), Terraform, or CI/CD work as initiatives require it - Cross-functional impact: collaborate with Product, Security, Analytics, and Medical teams, and engage with technology partners (Databricks, Google, OpenAI, Anthropic, AWS) on pre-release capabilities relevant to your features Experience and skills
- product sensibility: a track record of shipping user-facing features, with attention to latency, tone, and quality of AI output as experienced by end users - comfort picking up new infrastructure tools (Databricks, AWS, Terraform, GitHub Actions) as needed — deep prior expertise not required Nice to have:
- healthcare, regulated-industry, or safety-critical AI systems experience - data engineering fundamentals (Spark, Delta tables, Parquet) #LI-KP1 #LI-Hybrid
Your next step
Complete your application on job-boards.greenhouse.io. The employer’s form will show what is required.
Applying through Greenhouse
- No account needed: the form is one page, with an “Autofill my application” option that reads your resume.
- Greenhouse doesn’t read resumes over 2.5 MB, or details placed in a header, footer, text box, table or second column. The file still attaches, but a recruiter has to type you in by hand.
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Demand for AI Engineer roles
New AI Engineer postings at the employers we follow are up 134% over the last 6 weeks compared with the 6 before.
Each bar is one week of new postings. The darkest bars are the last 6 weeks.
Counted from the hiring pages we’ve followed for at least five weeks, so employers we add don’t look like growth. Updated weekly.
About the role
We file this job under AI Engineer, by the work the posting describes.
AI engineers build products on top of AI models that already exist, most often large language models: they connect a model to a company's data and tools and ship the assistants, agents and search features people use.
Postings ask for strong Python or TypeScript, experience with model APIs, retrieval and agent frameworks, and ways to test whether the model's answers are good enough.
An ML engineer trains and serves models; an AI engineer usually starts from a model someone else trained and builds the product around it, though titles often mix the two.
Job description
500M+ downloads. 80M+ monthly users. A decade of building – and we’re still accelerating.
Flo is the world’s #1 health & fitness app worldwide on a mission to build a better future for female health. Backed by a $200M investment led by General Atlantic, we became the first product of our kind to reach a $1B valuation in 2024 – and we’re not slowing down.
With 7M paid subscribers and the highest-rated experience in the App Store’s health category, we’ve spent 10 years earning trust at scale. Now, we’re building the next generation of digital health – AI-powered, privacy-first, clinically backed – to help our users know their body better.
The job
We are looking for a Senior AI Engineer with strong LLM and product engineering experience to join our AI Platform team and help ship the AI-driven features across our app — including personalized in-app content recommendations, conversational AI-powered insights, and AI-generated mobile push notifications. You will focus on the product-facing behavior of our GenAI features (relevance, quality, latency, and safety), using the platform’s judges, fine-tuning pipelines, and evaluation tools, and contributing to infrastructure work (Databricks, AWS, Terraform) as initiatives require it.
What you’ll do
- Feature development: build and ship LLM-powered product features, including AI-generated mobile push notifications, personalized in-app content recommendations and custom user journeys, and conversational AI-powered insights — including structured output such as charts and widgets
- Latency and UX: reduce perceived and actual response latency through streaming, pregeneration, and inference-time tradeoffs, working closely with product and design on how AI output is experienced by users
- Prompt and model behavior: iterate on prompt design and calibration, use fine-tuned health-domain models (Llama, Gemma, MedGemma) where relevant, and work with the Judge-as-a-Service ecosystem to keep outputs safe and high quality
- Experimentation: help enable A/B testing for model and prompt changes, using evaluation gates to ship safely and measure impact
- Data and evaluation: contribute to synthetic Q&A generation, golden test sets, and evaluation dataset design that supports the features you’re building
- Infrastructure: contribute to Databricks, AWS (EKS), Terraform, or CI/CD work as initiatives require it
- Cross-functional impact: collaborate with Product, Security, Analytics, and Medical teams, and engage with technology partners (Databricks, Google, OpenAI, Anthropic, AWS) on pre-release capabilities relevant to your features
Experience and skills
Must have:
- 7+ years of software engineering, with recent hands-on experience building product features backed by LLMs
- experience with at least one of: prompt engineering, LLM evaluation, fine-tuning, or model serving
- strong Python, and comfort working with APIs/SDKs that wrap LLM calls, prompt templates, and structured outputs
- product sensibility: a track record of shipping user-facing features, with attention to latency, tone, and quality of AI output as experienced by end users
- comfort picking up new infrastructure tools (Databricks, AWS, Terraform, GitHub Actions) as needed — deep prior expertise not required
Nice to have:
- LLM evaluation frameworks (judges, graders, calibration methodology) or fine-tuning techniques (LoRA, RLHF/DPO, model distillation)
- prompt optimisation frameworks (DSPy or similar)
- feature stores or personalization/ranking experience (relevant to in-app content recommendation work)
- healthcare, regulated-industry, or safety-critical AI systems experience
- data engineering fundamentals (Spark, Delta tables, Parquet)
#LI-KP1 #LI-Hybrid
Annual Salary Range (ranges may vary based on skills and experience)
£120,000—£180,000 GBP
How we work
We’re a mission-led, product-driven team. We move fast, stay focused and take ownership – from brief to build to impact. Debate is encouraged. Decisions are shared. We care about craft, ship with purpose, and always raise the bar.
You’ll be working with people who take their work seriously, not themselves. It takes commitment, resilience, and the drive to keep going when things get tough. Because better health outcomes are worth it.
What you'll get
We support impact with meaningful reward. Here’s what that looks like:
- Competitive salary and annual reviews
- Opportunity to participate in Flo’s performance incentive scheme
- Paid holiday, sick leave, and female health leave
- Enhanced parental leave and pay for maternity, paternity, same-sex and adoptive parents
- Accelerated professional growth through world-changing work and learning support
- In-person collaboration and work in a hybrid model, with 3 days per week spent in the office
- 5-week fully paid sabbatical at 5-year Floversary
- Flo Premium for friends & family, plus more health, pension and wellbeing perks
Diversity, equity and inclusion
Our strength is in our differences. At Flo, hiring is based on merit, skill and what you bring to the role – nothing else. We’re proud to be an equal opportunity employer, and we welcome applicants from all backgrounds, communities and identities. Read our privacy notice for job applicants.
Source details
Source notes
Source excerptsSelected passages from the saved posting. Check the full description for conditions and exceptions.
- Pay
Annual Salary Range (ranges may vary based on skills and experience) £120,000—£180,000 GBP How we work
- Location & working pattern
London
- data engineering fundamentals (Spark, Delta tables, Parquet) #LI-KP1 #LI-Hybrid Annual Salary Range (ranges may vary based on skills and experience)
More source context
- Accelerated professional growth through world-changing work and learning support - In-person collaboration and work in a hybrid model, with 3 days per week spent in the office - 5-week fully paid sabbatical at 5-year Floversary
- Work authorization
No clear work-authorization passage found. Eligibility is unconfirmed.