• Be part of an agile team to develop scalable, highly available core platform services.
• Participate and contribute to requirements analysis and architecture.
• Collaborate with product managers, architects, engineering leaders and test engineers.
• Understand performance and scalability principles and apply when developing software.
• Document and communicate clearly architecture and implementation solutions.
• Troubleshoot and support current platform in production.
• This position requires the ability to be part of on-call rotation, troubleshooting customer issues and drive issues to resolution.

• 8+ years of industry experience in server-side development.
• 4+ years of Java backend development.
• Experience with any public cloud platform.
• Deep knowledge and experience in building Spring Framework applications.
• Strong Computer Science fundamentals in design, data structures, algorithms, problem solving and complexity analysis.
• Strong multithreading knowledge and experience.
• Experience in designing and implementing RESTful and RPC interfaces.
• Experience in applying design patterns and separating concerns in a distributed system.
• Experience architecting, developing and deploying internet scale, distributed and mission critical services.
• Strong understanding of event-driven systems.
• Experience working with SQL and NoSQL databases and caches.
• Experience working within an Agile/Scrum team.
• Positive, self-motivated and enthusiastic attitude with a strong-sense of ownership.
• Strong communication skills, both verbal and written.

Benefits:

• Five9 Shares
• Bonus Scheme
• 10% Flexi Benefit
• Meal Allowance
• Medical Insurance
• Life Insurance 
• 25 day Annual Leave + Public Holidays

Our global voice team is looking for a committed, experienced Senior Software Engineer who is passionate about creating high performing, scalable, and resilient mission critical services that are the foundation of Five9’s next generation contact center platform. You will have the opportunity to combine what you already know with new learnings, crafting a bespoke solution that serves our customers and partners.

Responsibilities:

• Participate in an Agile scrum team which practices DevOps.
• Write clean and well-documented code and tests.
• Deliver your code as part of an overall solution running in the public cloud.
• Develop and enhance our Media Server to support real-time integrations with Large Language Models (LLMs) and other AI services.

Required Skills:

• 5+ years professional experience in software development, with some being written in C and/or C++.
• Hands-on experience writing software for real-time communications signaling and media protocols (SIP, RTP, etc.).
• Ability to methodically troubleshoot complex systems.
• Excellent communication and organization skills, and a sense of ownership.

 Technical Skills:

• Modern C++ (C++17+), RTP/SIP, audio codecs, SIP/SDP, ASR/TTS integration, AI APIs, cloud platforms (AWS/Azure/GCP), CI/CD, containers, SRE principles.

Benefits:

• Five9 Shares
• Bonus Scheme
• 10% Flexi Benefit
• Meal Allowance
• Medical Insurance
• Life Insurance 
• 25 day Annual Leave + Public Holidays

Our global voice team is looking for a committed, experienced Senior Software Engineer who is passionate about creating high performing, scalable, and resilient mission critical services that are the foundation of Five9’s next generation contact center platform. You will have the opportunity to combine what you already know with new learnings, crafting a bespoke solution that serves our customers and partners.

Responsibilities:

• Participate in an Agile scrum team which practices DevOps.
• Write clean and well-documented code and tests.
• Deliver your code as part of an overall solution running in the public cloud.
• Develop and enhance our Media Server to support real-time integrations with Large Language Models (LLMs) and other AI services.

Required Skills:

• 3+ years professional experience in software development, with some being written in C and/or C++.
• Ability to methodically troubleshoot complex systems.
• Excellent communication and organization skills, and a sense of ownership.

Preferred Skills:

• Hands-on experience writing software for real-time communications signaling and media protocols (SIP, RTP, etc.).

 Technical Skills:

• Modern C++ (C++17+), RTP/SIP, audio codecs, SIP/SDP, ASR/TTS integration, AI APIs, cloud platforms (AWS/Azure/GCP), CI/CD, containers, SRE principles.

Benefits:

• Five9 Shares
• Bonus Scheme
• 10% Flexi Benefit
• Meal Allowance
• Medical Insurance
• Life Insurance 
• 25 day Annual Leave + Public Holidays

📍 Porto Matosinhos | 🏢 2 Days in the Office 

QA at Capital On Tap 🚀

Our QA team thrives on a culture of shared success, where every voice helps shape the quality of our products. Rather than working in isolation, we are fully integrated into diverse product squads, ensuring that everyone is a valued technical partner. The team is currently driving an "automation-first" testing strategy. It’s a collaborative, supportive environment where we prioritise learning from each other and ensuring that everyone has the opportunity to thrive and grow.

What You'll Be Doing 🗃️

• Own manual and automated testing across the SDLC, working closely with Software Engineers and Product Managers to ensure product quality.
• Contribute to and expand automated test coverage within an agile team.
• Drive continuous improvement through POCs, refining QA processes, tools, and best practices.
• Investigate user-reported issues, perform hands-on technical testing, and create, manage, and track bug reports.
• Develop deep product and domain knowledge, supporting engineers and promoting shared responsibility for quality.
• Effectively prioritise work, manage risks, and escalate issues in a fast-paced environment.

Our Values & Culture 🌞

• Just Pilot: We never settle for “good enough”. We pilot new ideas fast, ask questions to figure it out, and scale quickly.
• Why Not Today? Fast is as slow as we go - speed and simplicity gives us a competitive advantage.
• Be a Buddy: We tap in from day one to help the team, we do the right thing even if it’s hard.
• Owners and Dates: We don’t chase people. If you own a task and agree to a date, the expectation is that it gets done.
• Feedback: We want our employees to flourish, so we regularly provide direct and constructive feedback.

We’re Looking For 🔎

• QA experience across web/mobile applications, covering functional, regression, performance, exploratory, manual, and automated testing.
• Understanding of end-to-end impact, risk, dependencies, and pragmatic bug prioritisation to inform QA strategy.
• Hands-on experience with test automation tools and frameworks (e.g. Selenium, Appium, Postman, RestSharp, xUnit/NUnit) and REST API testing.
• Proficiency in C# (or similar OOP languages) and JavaScript/TypeScript, with solid SQL Server querying and scripting skills.
• Experience working in CI/CD environments, implementing continuous testing practices across multiple teams.
• Highly detail-oriented, methodical, and proactive, with a strong bias for problem-solving, exploratory testing, and taking initiative.

Even if you don’t have all of the necessary skills, we still encourage you to apply.

Interview Process 🤝 

• First stage: 30-minute intro, CV review, and values with Talent Partner
• Second stage: 45-minute “Tech Chat” with Team Manager
• Final stage: 60-minute Code Pairing + 30-minute Stakeholder Interview with Engineering & Product

Diversity & Inclusion 🌈
We welcome, consider and encourage applications from anyone who shares our commitment to inclusivity. Join us in creating a space where authenticity thrives, and everyone can do their best work.

Great Work Deserves Great Perks
We try not to take ourselves too seriously (all the time) so we make sure our office is decked out with a pool table, arcade machine, beer tap, and a couple of office dogs thrown in for good measure. Check out our benefits:
🏥 Private Healthcare including dental and opticians services through Vitality
✈️ Worldwide travel insurance through Vitality
🎁 Anniversary Rewards (£250, £500, £750, 4-week fully paid sabbatical)
👛 Salary Sacrifice Pension Scheme up to 7% match
🚘 Octopus EV Salary Sacrifice Scheme
🏖️ 28 days holiday (plus bank holidays)
📖 Annual Learning and Wellbeing Budget
👪 Enhanced Parental Leave
🚲 Cycle to Work Scheme
🚂 Season Ticket Loan
💬 6 free therapy sessions per year
🐶 Dog Friendly Offices
🍫 Free drinks and snacks in our offices

Check out more of our benefits, values and mission here.

📍 Porto Matosinhos | 🏢 2 Days in the Office 

QA at Capital On Tap 🌞

Our QA team thrives on a culture of shared success, where every voice helps shape the quality of our products. Rather than working in isolation, we are fully integrated into diverse product squads, ensuring that everyone is a valued technical partner. The team is currently driving an "automation-first" testing strategy. It’s a collaborative, supportive environment where we prioritise learning from each other and ensuring that everyone has the opportunity to thrive and grow.

What You'll Be Doing 🗃️

• Own manual and automated testing across the SDLC, working closely with Software Engineers and Product Managers to ensure product quality.
• Contribute to and expand automated test coverage within an agile team.
• Drive continuous improvement through POCs, refining QA processes, tools, and best practices.
• Investigate user-reported issues, perform hands-on technical testing, and create, manage, and track bug reports.
• Develop deep product and domain knowledge, supporting engineers and promoting shared responsibility for quality.
• Effectively prioritise work, manage risks, and escalate issues in a fast-paced environment.

Our Values & Culture 🌞

• Just Pilot: We never settle for “good enough”. We pilot new ideas fast, ask questions to figure it out, and scale quickly.
• Why Not Today? Fast is as slow as we go - speed and simplicity gives us a competitive advantage.
• Be a Buddy: We tap in from day one to help the team, we do the right thing even if it’s hard.
• Owners and Dates: We don’t chase people. If you own a task and agree to a date, the expectation is that it gets done.
• Feedback: We want our employees to flourish, so we regularly provide direct and constructive feedback.

We’re Looking For 🔎

• QA experience across web/mobile applications, covering functional, regression, performance, exploratory, manual, and automated testing.
• Understanding of end-to-end impact, risk, dependencies, and pragmatic bug prioritisation to inform QA strategy.
• Hands-on experience with test automation tools and frameworks (e.g. Selenium, Appium, Postman, RestSharp, xUnit/NUnit) and REST API testing.
• Proficiency in C# (or similar OOP languages) and JavaScript/TypeScript, with solid SQL Server querying and scripting skills.
• Experience working in CI/CD environments, implementing continuous testing practices across multiple teams.
• Highly detail-oriented, methodical, and proactive, with a strong bias for problem-solving, exploratory testing, and taking initiative.

Even if you don’t have all of the necessary skills, we still encourage you to apply.

Interview Process 🤝 

• First stage: 30-minute intro, CV review, and values with Talent Partner
• Second stage: 45-minute “Tech Chat” with Team Manager
• Final stage: 60-minute Code Pairing + 30-minute Stakeholder Interview with Engineering & Product

Diversity & Inclusion 🌈
We welcome, consider and encourage applications from anyone who shares our commitment to inclusivity. Join us in creating a space where authenticity thrives, and everyone can do their best work.

Great Work Deserves Great Perks

Check out our benefits:

🏥 Private Healthcare through AdvanceCare
🎁 Anniversary Rewards (€280, €570, €860, 4-week fully paid sabbatical)

🚘 Paid Car Parking

🏖️ 36 days holiday (inclusive of public holidays with public holidays carried over if they fall on a weekend)
📖 Annual Learning and Wellbeing Budget
💬 6 free therapy sessions per year
🍫 Free drinks and snacks in our offices

🏡🏢This is a hybrid role, our engineering teams work from our Matosinhos office Office 2 days per week.

This is a multiple-headcount role, so please don't be put off if you've seen it advertised for a while.

What You’ll Be Doing
We’re looking for Senior Full stack Engineers to help us build the best credit card and payment products for small businesses. If you’re looking for an environment where you’re given the freedom to make empowered decisions, research new technologies, and learn/share knowledge with your peers. Then keep on reading!

• You’ll build robust and scalable solutions using .Net technology
• From the first line of code to production, monitoring, and continuous improvement - you’ll own the SDLC
• You’ll craft slick, responsive user interfaces with modern JavaScript frameworks (React), making sure our products don’t just work, they feel great to use
• Teamwork makes the dream work - you’ll partner with Product Managers, QA’s, and fellow Software Engineers
• You’ll build bulletproof unit and integration tests to keep our software sharp and our users happy
• Bugs happen. When they do, you’ll be ready to troubleshoot and tweak as needed
• You’ll bridge the gap between tech speak and business goals, ensuring everyone’s on the same page and moving forward together

We’re Looking For 🔎
Required skills:

• A minimum of 5+ years hands-on experience in C#, .Net Core, SQL Server, ideally JavaScript and React also!
• Good testing practices, in both Unit and Integration testing
• Good understanding of database technologies
• Experience in using Agile development practices
• A passion for learning new skills and technologies
• A proactive, supportive, and collaborative team player

Our Tech Stack

• Backend: C#, .Net, .Net Core
• Frontend: React, JavaScript
• Mobile: Flutter, Dart
• Databases: SQL Server, MongoDB
• Cloud: Azure & GCP

Interview Process 🤝

• First stage: 30-minute intro, CV review, and values with a Talent Partner
• Second stage: 45-minute “Tech Chat” with a Team Manager
• Final stage: 90-minute Code Pairing + 30-minute Values Interview

Diversity & Inclusion 🌈
We welcome, consider and encourage applications from anyone who shares our commitment to inclusivity. Join us in creating a space where authenticity thrives, and everyone can do their best work.

Great Work Deserves Great Perks

Check out our benefits:

🏥 Private Healthcare through AdvanceCare
🎁 Anniversary Rewards (€280, €570, €860, 4-week fully paid sabbatical)

🚘 Paid Car Parking

🏖️ 36 days holiday (inclusive of public holidays with public holidays carried over if they fall on a weekend)
📖 Annual Learning and Wellbeing Budget
💬 6 free therapy sessions per year
🍫 Free drinks and snacks in our offices

🏡🏢This is a hybrid role, our engineering teams work from our Matosinhos office Office 2 days per week.

This is a multiple-headcount role, so please don't be put off if you've seen it advertised for a while.

What You’ll Be Doing
We’re looking for Full stack Engineers to help us build the best credit card and payment products for small businesses. If you’re looking for an environment where you’re given the freedom to make empowered decisions, research new technologies, and learn/share knowledge with your peers. Then keep on reading!

• You’ll build robust and scalable solutions using .Net technology
• From the first line of code to production, monitoring, and continuous improvement - you’ll own the SDLC
• You’ll craft slick, responsive user interfaces with modern JavaScript frameworks (React), making sure our products don’t just work, they feel great to use
• Teamwork makes the dream work - you’ll partner with Product Managers, QA’s, and fellow Software Engineers
• You’ll build bulletproof unit and integration tests to keep our software sharp and our users happy
• Bugs happen. When they do, you’ll be ready to troubleshoot and tweak as needed
• You’ll bridge the gap between tech speak and business goals, ensuring everyone’s on the same page and moving forward together

We’re Looking For 🔎
Required skills:

• A minimum of 3+ years hands-on experience in C#, .Net Core, SQL Server, ideally JavaScript and React also!
• Good testing practices, in both Unit and Integration testing
• Good understanding of database technologies
• Experience in using Agile development practices
• A passion for learning new skills and technologies
• A proactive, supportive, and collaborative team player

Our Tech Stack

• Backend: C#, .Net, .Net Core
• Frontend: React, JavaScript
• Mobile: Flutter, Dart
• Databases: SQL Server, MongoDB
• Cloud: Azure & GCP

Interview Process 🤝

• First stage: 30-minute intro, CV review, and values with a Talent Partner
• Second stage: 45-minute “Tech Chat” with a Team Manager
• Final stage: 90-minute Code Pairing + 30-minute Values Interview

Diversity & Inclusion 🌈
We welcome, consider and encourage applications from anyone who shares our commitment to inclusivity. Join us in creating a space where authenticity thrives, and everyone can do their best work.

Great Work Deserves Great Perks

Check out our benefits:

🏥 Private Healthcare through AdvanceCare
🎁 Anniversary Rewards (€280, €570, €860, 4-week fully paid sabbatical)

🚘 Paid Car Parking

🏖️ 36 days holiday (inclusive of public holidays with public holidays carried over if they fall on a weekend)
📖 Annual Learning and Wellbeing Budget
💬 6 free therapy sessions per year
🍫 Free drinks and snacks in our offices

Responsibilities

We are looking for an exceptional Senior Software Engineer to join our growing team. In this role, you will be responsible for building API interfaces and backend infrastructure and collaborate with UI, connectivity and DevOps teams to come up with elegant solutions to complex problems. You will also be responsible to:

• Build complex Ruby on Rails applications.

• Build server side infrastructure for Workato user interface.

• Contribute in all phases of the development lifecycle

• Write well designed, testable, efficient code.

• Evaluate and propose improvements to existing system.

• Support continuous improvement by investigating alternatives and technologies and presenting these for architectural review.

Requirements

Qualifications / Experience / Technical Skills

• Strong experience developing, shipping and maintaining Rails applications (5+ years)

• Vast knowledge of Ruby

• BS/MS degree in Computer Science, Engineering or a related subject

• Solid knowledge of object-oriented programming and design

• Experience with Redis/Memcache based caching, RDBMS engines(Postgres)

• Solid knowledge of object-oriented programming and design

• Contributions to open source projects is a plus

Soft Skills / Personal Characteristics

• Excellent debugging, analytical, problem solving, and social skills

(REQ ID: 2380)