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Head of Engineering

Tony Tang

I lead teams that build and scale web products, and I'm taking my team AI-first.

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Highlights

About

I'm Tony, Head of Engineering at Fonts Ninja in Paris, with around 10 years of experience building web products. I lead a team of 5 developers: I choose our technologies, set our standards and make the final technical calls, and I have a direct say in the product direction. Before that, I spent 5 years at Planity, France's leading beauty booking platform, first as a developer and then leading a team of 4 to 6 developers. Today I focus on systems that handle large volumes of data, and on using AI to change how my team works. I have also mentored around 20 developers on Codementor.

What I can help with

Open to freelance (evenings & weekends)

Experience

  1. Feb 2026 – Present

    Head of Engineering · Fonts Ninja

    Makes a browser extension that identifies the fonts on any website (900k users on Chrome), and Font Radar, a service that finds websites using fonts without a license so that type foundries get paid.

    • Lead a team of 5 developers: I choose the technologies, set the standards and make the final call when the team disagrees on a solution.
    • Have a direct say in the product direction, in a smaller company with broader responsibilities than my previous role.
    • Hired 2 senior developers, one of whom now works with us remotely from Korea.
    • Taking the team AI-first: AI now triages our production errors, and both the developers and our Product Owner use AI to explore the codebase.
    • Leading the step-by-step modernisation of how we process data, planned to keep downtime to a minimum.

    How it was done

    • Set the team's coding standards and enforce hexagonal architecture through code review; I step into every project to validate solutions when developers have doubts.
    • Leading the migration from legacy database queues to BullMQ and Redpanda: easiest or most valuable parts first, every data flow mapped and each step planned.
    • Automated AWS and Sentry error triage with AI, and set up AI codebase analysis.

    Tech: NestJSTypeScriptNext.jsMySQLBullMQRedpandaAWS SQSAWS ECSAWS S3AWS LambdaCloudflareClaude Code

  2. Apr 2025 – Feb 2026

    Backend Developer · Fonts Ninja

    • Joined as a backend developer on the systems behind both products.
    • Worked on the Font Radar robots, which scan 30M new websites a day to find those most likely to be using fonts without a license.
    • Built and maintained many automations and data-collection tools.

    How it was done

    • Started migrating legacy database queues to BullMQ and Redpanda, so that many workers can run in parallel on an ever-growing database and their progress is easy to track.
    • Built and maintained web scrapers.

    Tech: NestJSTypeScriptMySQLBullMQRedpandaAWS SQSAWS ECSAWS S3AWS LambdaWeb Scraping

  3. Feb 2022 – Feb 2025

    Lead Developer · Planity

    France's leading beauty booking platform: 40,000+ salons and around 10M appointments a month, also in Belgium and Germany.

    • Led a team that grew from 4 to 6 developers over 3 years, one of the teams created as Planity scaled its engineering.
    • Mentored the developers I worked with: most of them were promoted, and some became Lead Developers themselves.
    • Estimated project timelines, planned delivery and reviewed the team's work for readability, correctness and security.
    • Led the zero-downtime move of the salon statistics dashboard to a new system: it became much faster, cheaper to run, and long-standing wrong totals were fixed.

    How it was done

    • Migrated the dashboard from Firebase to Elasticsearch, replacing precomputed caches with query-time aggregations.
    • Validated the approach with a proof of concept, then designed the migration: dual-writes, an idempotent and resumable backfill of millions of records with AWS Step Functions and Lambda, per-salon validation of every total, and a feature-flag cutover rehearsed in preprod.
    • Spent most of my time reviewing pull requests rather than writing code.

    Tech: ElasticsearchFirebaseAWS Step FunctionsAWS Lambda

  4. Feb 2020 – Feb 2022

    Fullstack Web Developer · Planity

    • Built features for the public booking app, on web and mobile, and for Planity Pro, the software salons use to run their business.
    • Built a point-of-sale system for salons in Germany, and integrated online payments and Shopify.
    • Designed large features, and planned releases so that customers still on older versions of the app kept working.

    How it was done

    • Worked on the AWS backend (Lambda, S3, API Gateway, OpenSearch) and on real-time updates with Firebase and Firestore.
    • Integrated Stripe and Shopify, and worked on database sharding.

    Tech: ReactReact NativeReduxXStateFirebaseFirestoreAWS LambdaAWS S3AWS API GatewayAWS OpenSearchAlgoliaStripeShopify

  5. Nov 2017 – Oct 2019

    Software Engineer · LCLwork-study

    French retail bank.

    • Added features to an internal banking application that many employees depended on every day.
    • Worked with other teams to integrate new features into the existing system.
    • Wrote automated tests to keep this business-critical application reliable.

    How it was done

    • The application was built on an older version of Java.

    Tech: Java

  6. Aug 2016 – Oct 2017

    Web Developer · FWAwork-study

    • Maintained a complex business web application.
    • Made database queries faster and took part in database migrations.

    How it was done

    • The application was built with C# and ASP.NET on the company's in-house template system.

    Tech: C#ASP.NETSQLMySQL

Education

Leadership skills

Technical details

For engineers: the skills, stack and projects behind the results above.

Technical skills

Languages & frameworks
TypeScriptNode.jsNestJSNext.jsReactReact NativeReduxXState
Architecture
System DesignHexagonal ArchitectureWeb Scraping
Data & messaging
SQLMySQLNoSQLElasticsearchBullMQRedpanda (Kafka)FirebaseFirestoreAlgolia
Cloud
AWS ECSAWS SQSAWS LambdaAWS S3AWS Step FunctionsAWS DynamoDBAWS API GatewayAWS OpenSearchCloudflare
AI
Claude CodeAI automation (LLMs)
Payments & commerce
StripeShopify

Projects

Contact