Freelance Technical Writer – Payments (Core Banking)

Tuum is a next-generation banking platform. We enable fintech and banks to rapidly offer seamless and tailored financial services to their customers. Our core banking platform is revolutionising the financial services industry. The platform is API-based, consisting of flexible and independent modules covering all retail and business banking capabilities for quick and easy integration. 
Launched in 2019, Tuum is headquartered in Tallinn and is backed by investors including Citibank, BlackFin Capital Partners, Karma Ventures, Portage Ventures, SpeedInvest, and CommerzVentures.
We are looking for a highly experienced Technical Writer (Freelance) to support the creation of onboarding and educational documentation for our core banking Payments module. The documentation scope includes business processes, API references, and flow/architecture diagrams.   This is a short-term engagement (approx. 2 months) focused on producing a complete set of documentation covering the full scope of Payments functionalities.

What you’ll be doing: Produce high-quality documentation focused on onboarding and usage of the core banking Payments module, ensuring clarity and usability for different audiences.

• Create structured onboarding guides and user documentation covering business processes, APIs reference/usage, and end-to-end system/architecture diagrams

• Translate complex technical and business concepts into clear, concise, and user-friendly content for audiences with varying levels of expertise

• Map API endpoints to business events and user actions, ensuring alignment between technical implementation and real-world use cases

• Collaborate with Product Owners and Business Analysts to gather requirements and ensure accuracy and completeness

• Work closely with the Academy and Customer Success teams to design and structure Payment-domain courses, learning paths and onboarding materials that facilitate customer and partner education and adoption.

• Propose and implement documentation standards, templates, and style guides (including standards for API reference documentation and diagrams)

• Where relevant, support creation of multimedia assets (tutorials, videos, visual guides), including visual explanations of flows and architecture

Who we’re looking for

• 3–5+ years of experience as a Technical Writer in fintech or SaaS environments, with a strong focus on payments processing

• Strong ability to understand complex systems and translate them into accessible and structured content.

• Excellent written English with a strong focus on clarity, tone, and accuracy

• Proven experience designing well-structured documentation and learning flows

• Hands-on experience working with APIs:

• Ability to read and understand API documentation

• Ability to map APIs to business events, workflows, and user actions

• Experience creating or contributing to flow diagrams and architecture diagrams

• Experience creating or managing e-learning content (LMS platforms, online courses, or training programs) would be a plus

We are an equal opportunity employer and value diversity at our company. We actively hire for cultural growth and welcome people of all ages, backgrounds and value people who take a journey unique to them. Equality, diversity and inclusion are our priority and we are committed to ensuring all job applicants are treated equally. All applicants will be treated fairly and will be considered for employment without discrimination because of ethnicity, race, religion or belief, gender, sexual orientation, gender identity or gender reassignment, family or parental status, pregnancy or maternity, marital or civil partner status, national origin, age, veteran, neurodiversity status or disability status.