Javascript Backend Developer Jobs in St Louis, MO

Integration Engineer II, AI & Engineering/Engineering as a Service

Join our AI & Engineering team in transforming technology platforms, driving innovation, and helping make a significant impact on our clients' success. You'll work alongside talented professionals reimagining and re-engineering operations and processes that are critical to business. Your contributions can help clients improve financial performance, accelerate new digital ventures, and fuel growth through innovation.
AI & Engineering leverages cutting-edge engineering capabilities to build, deploy, and operate integrated/verticalized sector solutions in software, data, AI, network, and hybrid cloud infrastructure. These solutions are powered by engineering for business advantage, transforming mission-critical operations. We enable clients to stay ahead with the latest advancements by transforming engineering teams and modernizing technology & data platforms. Our delivery models are tailored to meet each client's unique requirements.
Engineering as a Service provides complete design, implementation, and technology operations, leveraging our core engineering expertise. We transform engineering teams, modernize technology, and deliver complex programs with a product engineering approach. Our flexible delivery models-traditional teams, pools, or pods-are tailored to each client's needs, offering engineering-led advisory, implementation, and operational capabilities to accelerate innovation.
Recruiting for this role ends on 10/31/2026.
Work You'll Do
As Integration Engineer II you will have hands-on integration development skills to develop solutions streamlining business processes working with internal teams, near-shore, off-shore technologists and vendor relationships. You will be part of API management strategies to enable seamless communication between applications. You will work across geographies with accountability for the success, effectiveness and delivery of multiple work streams, managing a large, dispersed technology team.

Key Responsibilities

• Design end-to-end system architecture spanning frontend, backend, integration layers, and cloud infrastructure, translating requirements into scalable Azure-based solutions
• Define technical standards, Integration design patterns, and best practices to guide the development team
• Create and maintain architecture diagrams, technical specifications, and design documents, including data mapping and configuration details
• Build backend services and APIs using Python (e.g., FastAPI, Django, Flask), Javascript, Azure, Typescript or using enterprise integration tools like MuleSoft , Apigee, Kong, Workato, BizTalk.
• Design, build, and integrate RESTful APIs - connecting third-party and internal systems for reliable, consistent data exchange
• Implement API security (OAuth2, JWT, API keys), versioning, rate limiting, and robust error handling
• Manage the full software development lifecycle (SDLC), including developing, testing, and deploying integration processes across Test, UAT, and Production environments
• Monitor integration performance, proactively troubleshoot issues, and provide expert-level post-deployment support
• Collaborate with cross-functional teams to optimize data flows and ensure adherence to integration best practices
• Take ownership of assigned projects, manage stakeholder expectations, and mentor junior team members toward successful delivery 

A successful candidate would possess these skills:

• Ability to work independently and collaborate as part of a team
• Effective written and verbal communication skills
• Meticulous attention to detail and quality of work product
• Ability to build and sustain professional relationships
• Ability to lead projects or workstreams
• Ability to manage and prioritize multiple tasks in a fast-paced and dynamic environment
• Strong interpersonal skills and professional demeanor
• Ability to meet deadlines
• Ability to provide clear guidance to others

Qualifications

• Bachelor's degree in computer science, software engineering, information technology or a related field.
• 4+ years of hands-on experience with one or more modern programming languages (e.g., Python, JavaScript/TypeScript) for building backend services and APIs
• Proven experience designing and implementing integration solutions connecting disparate systems, applications, and data sources across on-premises and cloud environments
• Strong understanding of integration patterns and architectural styles (e.g., point-to-point, hub-and-spoke, event-driven, pub/sub, ESB, iPaaS)
• Hands-on experience with API design and development, including RESTful services, SOAP, and/or GraphQL
• Working knowledge of API security standards and protocols (OAuth2, JWT, SAML, API keys) and best practices for versioning, throttling, and error handling
• Experience with enterprise integration platforms/tools (e.g., MuleSoft, Apigee, Kong, Workato, BizTalk, Boomi, or equivalent)
• Experience with at least one major cloud platform (Azure, AWS, or GCP), including cloud-native architecture and deployment practices
• Solid understanding of data mapping, transformation, and orchestration techniques across heterogeneous systems
• Experience managing the full software development lifecycle (SDLC), including CI/CD pipelines, testing strategies, and deployment across multiple environments (Dev, Test, UAT, Production)
• Strong analytical and troubleshooting skills, with the ability to diagnose and resolve complex integration and performance issues
• Excellent communication skills, with the ability to translate business requirements into technical solutions and explain them to both technical and non-technical stakeholders
• Demonstrated ability to create clear technical documentation, including architecture diagrams, specifications, and data mapping references
• Experience leading or mentoring junior developers, with a collaborative approach to working across cross-functional teams
• Strong project ownership mindset, with the ability to manage priorities, timelines, and stakeholder expectations independently
• Ability to travel up to 50% of the time, based on the work you do and the clients and industries/sectors you serve.
•  Must be legally authorized to work in the United States without the need for employer sponsorship, now or at any time in the future. 

Preferred

• Exposure to and understanding of enterprise architecture frameworks (e.g. TOGAF)
• Experience integrating specific enterprise systems such as Salesforce, SAP, Oracle, HCM, Workday, etc.
• Familiarity with cloud technologies and architectures (AWS, Azure, GCP).

Wages and Salary
The wage range for this role takes into account the wide range of factors that are considered in making compensation decisions including but not limited to skill sets; experience and training; licensure and certifications; and other business and organizational needs. The disclosed range estimate has not been adjusted for the applicable geographic differential associated with the location at which the position may be filled. At Deloitte, it is not typical for an individual to be hired at or near the top of the range for their role and compensation decisions are dependent on the facts and circumstances of each case. A reasonable estimate of the current range is $86,700-$170,900. 

You may also be eligible to participate in a discretionary annual incentive program, subject to the rules governing the program, whereby an award, if any, depends on various factors, including, without limitation, the individual, and organizational performance.

Integration Engineer II, AI & Engineering/Engineering as a Service

Join our AI & Engineering team in transforming technology platforms, driving innovation, and helping make a significant impact on our clients' success. You'll work alongside talented professionals reimagining and re-engineering operations and processes that are critical to business. Your contributions can help clients improve financial performance, accelerate new digital ventures, and fuel growth through innovation.
AI & Engineering leverages cutting-edge engineering capabilities to build, deploy, and operate integrated/verticalized sector solutions in software, data, AI, network, and hybrid cloud infrastructure. These solutions are powered by engineering for business advantage, transforming mission-critical operations. We enable clients to stay ahead with the latest advancements by transforming engineering teams and modernizing technology & data platforms. Our delivery models are tailored to meet each client's unique requirements.
Engineering as a Service provides complete design, implementation, and technology operations, leveraging our core engineering expertise. We transform engineering teams, modernize technology, and deliver complex programs with a product engineering approach. Our flexible delivery models-traditional teams, pools, or pods-are tailored to each client's needs, offering engineering-led advisory, implementation, and operational capabilities to accelerate innovation.
Recruiting for this role ends on 10/31/2026.
Work You'll Do
As Integration Engineer II you will have hands-on integration development skills to develop solutions streamlining business processes working with internal teams, near-shore, off-shore technologists and vendor relationships. You will be part of API management strategies to enable seamless communication between applications. You will work across geographies with accountability for the success, effectiveness and delivery of multiple work streams, managing a large, dispersed technology team.

Key Responsibilities

• Design end-to-end system architecture spanning frontend, backend, integration layers, and cloud infrastructure, translating requirements into scalable Azure-based solutions
• Define technical standards, Integration design patterns, and best practices to guide the development team
• Create and maintain architecture diagrams, technical specifications, and design documents, including data mapping and configuration details
• Build backend services and APIs using Python (e.g., FastAPI, Django, Flask), Javascript, Azure, Typescript or using enterprise integration tools like MuleSoft , Apigee, Kong, Workato, BizTalk.
• Design, build, and integrate RESTful APIs - connecting third-party and internal systems for reliable, consistent data exchange
• Implement API security (OAuth2, JWT, API keys), versioning, rate limiting, and robust error handling
• Manage the full software development lifecycle (SDLC), including developing, testing, and deploying integration processes across Test, UAT, and Production environments
• Monitor integration performance, proactively troubleshoot issues, and provide expert-level post-deployment support
• Collaborate with cross-functional teams to optimize data flows and ensure adherence to integration best practices
• Take ownership of assigned projects, manage stakeholder expectations, and mentor junior team members toward successful delivery 

A successful candidate would possess these skills:

• Ability to work independently and collaborate as part of a team
• Effective written and verbal communication skills
• Meticulous attention to detail and quality of work product
• Ability to build and sustain professional relationships
• Ability to lead projects or workstreams
• Ability to manage and prioritize multiple tasks in a fast-paced and dynamic environment
• Strong interpersonal skills and professional demeanor
• Ability to meet deadlines
• Ability to provide clear guidance to others

Qualifications

• Bachelor's degree in computer science, software engineering, information technology or a related field.
• 4+ years of hands-on experience with one or more modern programming languages (e.g., Python, JavaScript/TypeScript) for building backend services and APIs
• Proven experience designing and implementing integration solutions connecting disparate systems, applications, and data sources across on-premises and cloud environments
• Strong understanding of integration patterns and architectural styles (e.g., point-to-point, hub-and-spoke, event-driven, pub/sub, ESB, iPaaS)
• Hands-on experience with API design and development, including RESTful services, SOAP, and/or GraphQL
• Working knowledge of API security standards and protocols (OAuth2, JWT, SAML, API keys) and best practices for versioning, throttling, and error handling
• Experience with enterprise integration platforms/tools (e.g., MuleSoft, Apigee, Kong, Workato, BizTalk, Boomi, or equivalent)
• Experience with at least one major cloud platform (Azure, AWS, or GCP), including cloud-native architecture and deployment practices
• Solid understanding of data mapping, transformation, and orchestration techniques across heterogeneous systems
• Experience managing the full software development lifecycle (SDLC), including CI/CD pipelines, testing strategies, and deployment across multiple environments (Dev, Test, UAT, Production)
• Strong analytical and troubleshooting skills, with the ability to diagnose and resolve complex integration and performance issues
• Excellent communication skills, with the ability to translate business requirements into technical solutions and explain them to both technical and non-technical stakeholders
• Demonstrated ability to create clear technical documentation, including architecture diagrams, specifications, and data mapping references
• Experience leading or mentoring junior developers, with a collaborative approach to working across cross-functional teams
• Strong project ownership mindset, with the ability to manage priorities, timelines, and stakeholder expectations independently
• Ability to travel up to 50% of the time, based on the work you do and the clients and industries/sectors you serve.
•  Must be legally authorized to work in the United States without the need for employer sponsorship, now or at any time in the future. 

Preferred

• Exposure to and understanding of enterprise architecture frameworks (e.g. TOGAF)
• Experien...