API Support Engineer

JobsCloseBy Editorial Insights

B4B Payments is seeking an API Support Engineer in London, hybrid, with permanent or contract, full-time hours. The role sits at the crossroads of engineering, client success, and pre-sales, serving as the primary technical contact for integrating partners and guiding sandbox configurations through the full implementation lifecycle. Expect a meaningful ramp-up, deep product knowledge, and a hands-on mindset beyond a first-line support role. Essential skills include REST APIs, authentication, Postman, SQL, basic scripting, and systematic debugging. 2–5+ years in technical support or integration engineering, ideally in payments or fintech. Apply by sending your CV with location and UK work eligibility; agencies and visa sponsorships are not considered.

Job Title: API Support Engineer

Location: London /Hybrid  

Term: Permanent / Contract / Full-time 

ABOUT US: 

B4B Payments is a multi-award-winning, global financial services technology company offering an advanced transaction payments platform and APIs for emerging payments and financial services. Our flexible technology and comprehensive services include embedded finances, payment accounts, FX, rapid payouts, physical and virtual card issuing, and BIN sponsorship.

With 20 years of expertise in payments, B4B Payments is headquartered in the UK. In Europe, B4B Payments is regulated as an e-money institution (EMI) authorised by the Financial Conduct Authority (FCA) and the Bank of Lithuania and is a Mastercard® Principal Member.

B4B Payments’ US division (B4B Payments USA, Inc. ) is based in Boston, MA, and specialises in enabling companies to reduce costs and increase efficiency in managing corporate expenditure and global payouts.

B4B Payments Europe and US divisions offer full and partial program management and support, in addition to comprehensive technical, regulatory, and service support to fintechs looking to launch or grow domestically and internationally.

B4B Payments is a Banking Circle Group company. A next-generation financial technology platform for global commerce, Banking Circle Group comprises a rich set of complementary e-commerce solutions. From international cross-border payments, accounts and liquidity management, and embedded finance to business payments & card issuing, B2B Buy Now Pay Later, and account-to-account payment methods, the ecosystem is delivering modern financial solutions to 

some of the largest and most successful companies around the world, as they accelerate the digitalisation of their customer and supply-chain.

ABOUT THE ROLE:

We are looking for an API Support Engineer to join our Technical Operations team. This is a hands-on technical role sitting at the intersection of engineering, client success, and pre-sales. You will be the primary technical point of contact for our integrating clients and partners: guiding them through API integration, configuring their sandbox environments, and owning the technical relationship through the full implementation lifecycle.

Given the complexity of our products, there is a meaningful ramp-up period. You will work closely with the CTO initially to build deep product knowledge before taking on partner relationships independently. This is not a first-line helpdesk role: we expect you to get under the hood, diagnose issues, take ownership and drive resolutions.

RESPONSIBILITIES: 

What You Will Do

Partner Integration Support

• Serve as the primary technical contact for clients and partners during their API integration and onboarding phase
• Provide hands-on support for API queries: diagnosing issues, reviewing request/response payloads, and guiding partners to resolution
• Configure and manage client environments in our sandbox, including product configuration and test data setup
• Own the technical integration journey end-to-end for each partner: both responding to inbound queries and proactively managing progress
• Coordinate with internal engineering and product teams to escalate and resolve complex technical issues

Pre-Sales Technical Support

• Partner with the sales team to provide technical input during the pre-sales process
• Respond to technical questions from prospective clients, assess integration feasibility, and articulate our API capabilities clearly
• Participate in technical discovery calls and solution scoping with prospects

Documentation & Knowledge

• Contribute to API documentation, integration guides, developer FAQs, and sandbox setup guides alongside the product and engineering teams
• Capture recurring integration issues and contribute to internal knowledge base articles to reduce repeat queries
• Support continuous improvement of the onboarding experience by feeding partner feedback into product and engineering

EXPERIENCE: 

Essential Criteria

Technical Skills (Required)

• Solid understanding of REST APIs: authentication, request/response structure, error handling, pagination
• Proficient with API testing tools such as Postman or equivalent
• Able to read and interpret logs, identify root causes, and debug integration issues systematically
• Comfortable with SQL for querying data and investigating issues
• Basic scripting ability (any language) to automate tasks or reproduce issues

Working in an AI-Enabled Business

• B4B is an AI-enabled business and we expect everyone to work that way. You should be comfortable using AI tools as a standard part of how you investigate, document, and resolve problems, and be willing to adopt new tools and workflows as they emerge. We are not looking for people who see AI as a threat or a novelty: we are looking for people who treat it as a force multiplier and apply good judgement about where it helps and where human review is essential.

Experience & Background

• 2–5+ years of experience in a technical support, solutions engineering, or integration engineering role
• Prior experience in payments or fintech is strongly preferred: familiarity with card issuing, payment schemes (Visa/Mastercard), or related financial infrastructure is a significant advantage
• For the right candidate with strong technical depth, we are open to backgrounds outside of fintech where genuine aptitude and appetite to learn the domain is demonstrated
• Experience supporting or implementing API-based integrations at a B2B or platform level

Personal Attributes

• Clear and confident communicator: able to translate technical complexity for both developer and non-developer audiences
• Comfortable managing client relationships during implementation. This is an important client facing role
• Self-directed and organised: capable of managing multiple partner integrations simultaneously without dropping threads
• Genuinely curious about complex technical systems and motivated to develop deep product expertise
• Comfortable in an environment where the product is nuanced and the answers are not always obvious
• Collaborative: works well with engineering, product, and commercial teams

Desirable Criteria  (nice to have) 

• Experience with SEPA, Faster Payments, or SWIFT payment rails
• Exposure to PCI DSS, FCA-regulated environments, or financial compliance requirements
• Familiarity with Mastercard or Visa scheme rules and card issuing concepts
• Experience writing or maintaining developer-facing technical documentation

Make a difference:

We are always on the lookout for talented individuals to help take us further - it is important to us to hire the right people for roles that work for both us and the individual.All interview processes will assess the following behaviours:

• Ownership & Accountability: We take responsibility for outcomes, not just tasks.
• Drive, Ambition & Initiatives: We move fast, think big, and don't wait to be asked.
• Positive Mindset & Resilience: We solve problems with energy, even when the path isn't clear
• Collaboration & Trust: We work together openly, with each other, with clients and with partners
• Customer & Commercial Focus: Every decision starts with the customer and ends with the values delivered.

What we offer 

• 25 days annual leave 
• Annual wellness day off 
• Access to one-to-one confidential counselling sessions through our Employee Assistance Programme 
• Access to retail & other discounts 
• Vitality health care plan  
• Access to ‘’Nous Finance-a smart way to save money’’   
• Learning & development support 
• Ride-to-work scheme
• Regular socials and a relaxed working environment 

NOTE:

We kindly request that you contact us by submitting your CV, indicating your current location, and confirming your eligibility to work in the United Kingdom. We assure you that our team will promptly respond to your inquiry.

Please note that we are not considering inquiries or applications from Agencies. Additionally, we regret to inform you that we are unable to provide visa sponsorships at this time