Senior Applied NLP Research Engineer

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….

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.

You will join the Assisted Creation team in R&D. Think of Assisted Creation as a co-pilot for video production—a “virtual director” that orchestrates all the necessary components to create professional-looking videos. Whether a user wants to make a company presentation, an advertisement, or a training video, Assisted Creation ensures users with different levels of expertise in video making can create high quality and engaging videos.

In this role, you’ll tackle both short-term product needs and long-term R&D goals. You will:

• Understand the business use cases and product needs and translate them into actionable ML problems.
• Determine data requirements and define appropriate data pipelines to support your solutions.
• Design metrics that optimise not just model performance but real-world user experience and business impact.
• Develop baseline models and iteratively improve them through experimentation and benchmarking.
• Collaborate with product, design, and research teams to ensure your work is aligned and impactful.
• Take ownership of ambitious projects and help shape the future direction of the product.

• MSc or PhD in Computer Science, Natural Language Processing or a related discipline.
• You have 5+ years of experience leading end-to-end NLP/ML projects—from problem formulation and data gathering to model training, benchmarking, and release.
• You have hands-on experience applying Large (Multimodal) Language Models to complex business applications.
• You’re familiar with fine-tuning open-source LLMs for specialised tasks or domains.
• Strong software development skills and experience across the stack: Python, PyTorch, Docker, Git, and an understanding of good software engineering practices (e.g., testing, code reviews).
• You possess excellent verbal and written communication skills in English and a genuine passion for what you do.
• … and above all you are passionate about what you do!

• Experience with other modalities such as Computer Vision or Audio.

• Very competitive compensation (salary + stock options + bonus)
• Hybrid work setting with an office in central London.
• 25 days of annual leave + public holidays
• 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
• + other benefits depending on your location

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

#LI-MD1