Salma Elmasry

I build data platforms people can ask questions of, and trust the answers.

Principal Data Engineer at Dose Daily. Eight years building cloud data infrastructure on BigQuery and Snowflake for small, fast-moving teams: vendor migrations, cost control, and AI analytics with guardrails.

An example of how a governed question runs

AskCancellations last month, by plan?

SELECT plan, COUNT(*) AS cancellations
FROM subscriptions
WHERE cancelled_at BETWEEN @month_start AND @month_end
GROUP BY plan
  • Read-only: SELECT statements only
  • Partition filter present
  • Dry run is inside the scan budget
  • Metric matches the approved definition

Recent work at Dose Daily

Oliver, a governed AI analyst
Leaders ask business questions in Slack or a web app and get validated, read-only answers from BigQuery. Includes a metric library, specialist agents for retention, acquisition, churn and funnel, and an approval step for new metric definitions.
BigQuery MCP server
A production Model Context Protocol server with a read-only SQL guard and schema discovery, so analysts get safe AI access to the warehouse.
Leaving a pipeline vendor
Led the move off Hevo to a native Shopify-to-BigQuery pipeline, with parallel validation and cutover runbooks.Cloud Functions, Polars, partition-scoped MERGE
Customer data platform
Primary engineer on a warehouse-first customer data platform, working with the dev team: Dataform marts, reverse ETL into Klaviyo and Iterable, and RudderStack Profiles monitoring.
Subscription migration
Led the move from StayAI to Skio for subscription management.
Retail partner ingest
Designed an ingest from a partner file service through Cloud Storage into BigQuery: 61 reports into 13 tables, with MERGE logic, data-quality checks, and Slack alerts.

Results at Seed Health

Results from July 2023 to October 2025
What I didResult
Replaced Fivetran with a custom pipelinePipeline budget down 50%
Renegotiated the Snowflake contract and tuned usageCommitted spend down 60%+, plus an extra year at no cost
Automated dependencies in Apache AirflowManual intervention down 70%
Added monitoring and Slack alerts through the dbt APICritical job failures down 50%
Wrote scripts to convert Snowflake SQL into dbt modelsAnalyst time down 60% during the migration
Generated a data dictionary with Snowflake CortexStakeholder back-and-forth down 40%

Experience

Nov 2025 to now
Principal Data Engineer, player-coachDose Daily, remote
Jul 2023 to Oct 2025
Senior Data EngineerSeed Health, remote
Jan 2021 to Jul 2023
Python Data Engineer IIFortune Magazine, New York
2018 to 2020
Data Scientist, Data Engineer, Software Engineer IIGradio, CarOpp, Cognizant
2021
M.S. in Applied StatisticsThe City University of New York, GPA 3.96

Blog

Posts on this site, and older technical notes on Medium. All posts or follow by RSS.

What we refused to let our AI analyst do
How a read-only analyst on BigQuery got its design from a list of things it would never do. October 2026.
Scheduling ETL jobs on AWS
How to automate data extraction jobs that run on EC2. August 2021.
Python environments with GitHub Actions
Automating checks on a GitHub-hosted project so pull requests stop breaking the code. January 2021.
Multiprocessing and pickle
Fixing serialization errors in multiprocessing code, including the dill package. December 2020.

Tools I work with

Cloud and warehouses. Google Cloud Platform (BigQuery, Cloud Functions, Cloud Run, IAM), AWS (EC2, S3, RDS), Snowflake including Cortex.

Engineering. Python, SQL, Polars, Spark, Apache Airflow, dbt, Dataform, Apache Kafka, Docker, CI/CD.

AI and governance. MCP servers, governed AI analytics, IAM governance, data quality, data modeling.

Customer data. Segment, RudderStack, Mixpanel, Klaviyo, Iterable, Shopify, Skio, Gorgias.