Mathieu Santostefano
Tech Expert / Symfony Core Team member
Tech Expert / Membre de la Core Team Symfony
Niort, France
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As a developer for almost 15 years, I work with Symfony on a daily basis. Having worked with almost every version since 1.4, I have followed the evolution of the entire PHP ecosystem, eventually becoming an active contributor and joining the Symfony Core Team in 2021! My favorite topics are about i18n, authentication / authorization, performance and software architecture.
Still passionate about this community and its enthusiasm, I enjoy sharing my experience on stage at conferences such as SymfonyLive, SymfonyCon, API Platform Con or Confoo!
En tant que développeur depuis près de 15 ans, je travaille quotidiennement avec Symfony. Ayant utilisé presque toutes les versions depuis la 1.4, j'ai suivi l'évolution de l'ensemble de l'écosystème PHP, pour finalement devenir un contributeur actif et rejoindre la Core Team de Symfony en 2021 ! Mes sujets de prédilections sont l'i18n, l'authentification / authorisation, la performance et l'architecture logicielle.
Toujours passionné par cette communauté et son enthousiasme, j'aime partager mon expérience sur scène lors de conférences telles que SymfonyLive, SymfonyCon, API Platform Con ou Confoo !
Area of Expertise
Topics
Unveil Symfony AI en
Last July 2025, the Symfony AI was launched as an initiative, just like Symfony UX, to help developers integrate AI into their apps with ready-to-use components and bundles.
In this talk, let’s discover Symfony AI’s origins, explore its components, and learn how to use them with any AI platform. We’ll also cover how to get started using it in your PHP apps and contribute to the project!
OIDC in Symfony: from token to real user login en
A step by step walkthrough of the OpenID Connect authorization code flow and how it is implemented in Symfony: redirect to the identity provider, callback, code exchange, session creation, state, PKCE, nonce, id_token validation, key rotation, federated logout. Based on a contribution to the framework, for anyone integrating any OIDC identity provider without repeating the classic mistakes.
Your AI app has no plan B en
Provider failover, cost and latency based routing, retries and circuit breakers that survive streaming, budget caps, token level observability: the resilience patterns an application needs once it calls LLMs in production, plus a comparison of managed gateways, open source gateways and rolling your own. Attendees leave with a helping decision grid and a comparison of existing solutions.
Playwright without JavaScript: your tests in PHP en
Chromium, Firefox and WebKit driven from PHP through a synchronous, typed API: locators by role and label, assertions that retry until the expected state appears, replayable traces holding DOM, network and console. On the menu: PHPUnit integration, a Symfony bundle that routes requests through the test kernel, migrating Mink or Behat tests, installing browsers in CI. You will write your end-to-end tests in pure PHP!
Mago: analyzing, linting and formatting PHP in Rust en
Mago combines static analysis, linting and formatting in a single Rust binary, with no PHP runtime and far faster than current tooling. On the menu: configuration, compatibility with PHPStan and Psalm annotations, generics and conditional types, pre-commit, CI and editor integration, all demonstrated on a real codebase. Enough to plan a gradual migration and speed-up your CI.
Symfony Messenger in production: what actually breaks en
Long running workers and memory growth, closed entity managers, messages handled twice, dispatching inside a transaction that rolls back, deploys breaking deserialization, retries and the failure transport, scaling, monitoring: the traps of running Symfony Messenger in production, drawn from public write-ups, post-mortems and upstream issues, each with symptom, cause and fix.
Symfony, Mercure, and an LLM raise a chat(bot). en fr
For several years now, we have known how to create chats between two human users. With the advent of LLMs, we are led to design these same chats but between a human and an LLM. Let's see together how to leverage proven software components, combined with recent AI technologies, to create a real-time chat between a human user and an LLM. On the technical agenda: Symfony AI, Mercure, and SSE client in PHP.
Mercure, SSE, API Platform et un LLM élèvent un chat(bot) en fr
Voilà plusieurs années que l'on sait bien faire des chats entre 2 utilisateurs humains. Avec l'arrivée des LLMs, nous sommes ammenés à concevoir ces mêmes chats mais entre un humain et un LLM.
Voyons ensemble comment tirer partie de briques logicielles éprouvées, aliées aux récentes technologies d'IA pour parvenir à créer un chat temps réel entre un utilisateur humain et un LLM.
Au programme technique: Symfony AI, Mercure et client SSE en PHP
APIs protected, the modern way en fr
Protecting an API hasn't always been easy, but in recent years authentication has become standardized, and modern, robust solutions have emerged.
You may have come across Oauth2, OIDC, SAML, JWT keywords in the past years. These are the technologies that will form the foundations for securing your APIs. Then, how to protect your resources from abuse? Rate limiting, IP/Geo blocking, WAF, etc.
We're going one step further, with dedicated tools and brand new features of Symfony, that will save us the trouble of implementing such protocols and techniques.
Whether you're developing your own API, or a customer of an external API, come and learn how to work securely without losing your head!
Des APIs protégées sans perdre la tête en fr
La protection d'une API n'a pas toujours été facile, mais ces dernières années, l'authentification a été standardisée. Des solutions modernes et robustes ont vu le jour.
Vous avez peut-être rencontré les mots-clés Oauth2, OIDC, SAML, JWT au cours des dernières années. Ce sont les technologies qui sont les fondations de la sécurisation de vos API. De plus, comment protéger vos ressources des abus ? Restrictions d'usage, IP/Geo blocage, WAF, etc. Mais nous irons plus loin, avec des outils adaptés et les toutes nouvelles fonctionnalités de Symfony, qui nous éviteront d'avoir à implémenter des protocoles et techniques complexes en PHP.
Que vous développiez votre propre API ou que vous soyez client d'une API externe, venez apprendre à travailler en toute sécurité sans perdre la tête !
Translate the UIs of your Sylius applications efficiently en
Leverage Symfony’s Translation component to efficiently translate the UIs of your Sylius applications.
This talk will cover best practices, tips, and tricks for managing translations in Sylius, ensuring your application is accessible to a global audience.
From translation keys extractions to SaaS tools used to translate your static texts, this talk will cover everything you need to know to efficiently translate the UIs of your Sylius applications.
API Platform Conference 2026
Des APIs sécurisées sans perdre la tête
ConFoo 2026
Unveil Symfony AI
APIs secured, the modern way
SymfonyCon Amsterdam 2025
Workshop - Mastering OOP & Design Patterns
API Platform Conference 2025
Mercure, SSE, API Platform et un LLM élèvent un chat(bot)
SymfonyOnline June 2025
Mastering OOP & Design Patterns
SyliusDays 2025
Translate the UIs of your Sylius applications efficiently
SymfonyLive Paris 2025
Lightning Talk - L'année des agents GenAI
SymfonyCon Brussels 2023
Workshop - From 0 to master the translation of your app
SymfonyLive Paris 2023
Lightning Talk - Au moins 4 façons de définir un DateTime avec un Time réinitialisé
SymfonyCon Disneyland Paris 2022
Painless authentication with Access Tokens
SymfonyWorld 2020
Internationalize your Symfony application
SymfonyLive Paris 2019
Des images au cordeau pour vos applications Symfony
PHP Tour Montpellier 2018
Traduire efficacement une application Symfony
SymfonyLive Paris 2018
Traduire efficacement une application Symfony
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