Sr. Machine Learning Engineer - R&D (NLP)

Who are we?

From your everyday PowerPoint presentations to Hollywood movies, AI will transform the way we create and consume content.
Today, people want to watch and listen, not read — both at home and at work. If you’re reading this and nodding, check out our brand video.

Despite the clear preference for video, communication and knowledge sharing in the business environment are still dominated by text, largely because high-quality video production remains complex and challenging to scale—until now….

Meet Synthesia

We're on a mission to make video easy for everyone. Born in an AI lab, our AI video communications platform simplifies the entire video production process, making it easy for everyone, regardless of skill level, to create, collaborate, and share high-quality videos. Whether it's for delivering essential training to employees and customers or marketing products and services, Synthesia enables large organizations to communicate and share knowledge through video quickly and efficiently. We’re trusted by leading brands such as Heineken, Zoom, Xerox, McDonald’s and more. Read stories from happy customers and what 1,200+ people say on G2.

In 2023, we were one of 7 European companies to reach unicorn status. In February 2024, G2 named us as the fastest growing company in the world. In 2025 we announced our series D funding. In total we’ve raised over $330M in funding from top-tier investors, including NEA, Atlassian Ventures, WiL, PSP Growth, and existing investors such as Accel, Nvidia, Kleiner Perkins, GV and top founders and operators including Stripe, Datadog, Miro, Webflow, and Facebook.

The Assisted Creation product is central to that mission. It further simplifies video creation by building an AI-based co-pilot for Synthesia. Our goal is to provide users, regardless of their prior video editing experience, with intuitive tools that ensure their success on our platform. To get started, users only need to supply an initial idea, which we turn into a video draft in seconds. Our solution uses a modern machine-learning stack based on LLMs, LVMs, embeddings, and more.

What will you be doing?

This role is a collaboration between the NLP team and the Assisted Creation team in the product.
The NLP team is part of the R&D team and is responsible for prototyping solutions for longer term challenges that involve language understanding.
The Assisted Creation team is responsible for integrating and delivering the solutions to the product.
In this role you will sit within the NLP team and work on long term solutions for the Assisted Creation project by coming up with suitable ML solutions and thinking about / recommending the required data and data pipeline. We believe in ownership, so you will have sole ownership of your projects which can be long term. You will be working with the product manager responsible for the Assisted Creation. Therefore it’s important to be able to communicate and understand product needs. As a result you will have the opportunity to shape the direction of the product.

Furthermore you will be responsible for:

• Developing ML models, data processing pipelines, evaluation, and making sure that the solutions are deployable to the product.
• Evaluating your work, and leveraging our data pipeline and frameworks that we have established to understand the impact your features have on our commercial objectives and pivoting where necessary.
• Breaking down a problem into small steps that can be delivered and validated iteratively is important.

Who are you?

• You have prior experience fine-tuning and deploying LLMs, ideally with open-source models.
• You have 5+ years of experience working in machine learning with experience in NLP.
• You have experience building performant ML based applications.
• Experience with CV and Diffusion models is a plus.
• Experience collaborating with Product Managers (cross team collaboration)
• And most importantly..You have excellent verbal and written communication skills in English and you are passionate about what you do!

The good stuff

• Attractive compensation  (salary + stock options + bonus)
• Hybrid work setting with an office in London (we need you to be in London, or in the EU and willing to relocate)
• 25 days of annual leave + public holidays
• Pension + Healthcare
• Work in a great company culture with the option to join regular planning and socials at our hubs
• A generous referral scheme when you know people that are amazing for us
• Strong opportunities for your career growth

You can see more about Who we are and How we work here: https://www.synthesia.io/careers

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