Senior Backend Engineer, Multi-Channel Messaging

PayJoy, Inc; United States; Hybrid; USD 268,000 - 275,000; Full time

Job summary

PayJoy, Inc. is seeking a Senior Software Engineer for the Communications Platform to design and build a consolidated, reliable messaging system across SMS, email, and WhatsApp.

You will partner with Identity, Fraud, CDP, and Onboarding teams to deliver scalable, observable infrastructure. You will implement APIs with strong SLAs, drive multi-tenant data models, and ensure regulatory compliance across international markets while mentoring engineers and contributing to platform-wide technology

Qualifications

• Bachelor's degree in Computer Science, Software Engineering, or equivalent practical experience.
• 5+ years of software engineering experience focusing on backend infrastructure and distributed systems.
• Hands-on experience with messaging channels (SMS, Email, Push, WhatsApp) and platforms like Twilio, Infobip, or SendGrid.
• Experience designing multi-tenant APIs and internal platform services with clear SLAs and versioning controls.
• Familiarity with event-driven architecture and streaming technologies such as Kafka, AWS SQS/SNS, or RabbitMQ.
• Strong data modeling skills, including unifying user identity records across disparate systems.
• Proficiency with system resilience patterns (retries, idempotency, rate limiting, failover) and monitoring tools like Datadog.
• Strong proficiency with Git, Kubernetes, and cloud platforms like AWS or GCP.
• Proficiency in core backend languages; PHP framework experience (Slim or Laravel) is a plus.
• Knowledge of international messaging compliance, consent management, and suppression rules is desirable.
• Background in fintech, digital lending, or regulated global industries is preferred.
• Track record of executing zero-downtime production migrations.
• Strong analytical and structured problem-solving skills.
• Excellent cross-functional communication and stakeholder management capabilities.
• Adaptable mindset with a passion for continuous learning and modern platform practices.
• Strong sense of ownership, personal accountability, and technical precision.
• Effective task prioritization and time management in a fast-paced engineering environment.

Responsibilities

• Design and build a centralized contact repository linking phone numbers, emails, hardware IDs, and user accounts.
• Establish internal notification APIs with well-defined contracts, semantic versioning, clear documentation, and strict SLAs.
• Implement dynamic traffic routing, vendor failover, and end-to-end delivery monitoring across providers like Twilio, Infobip, and WhatsApp.
• Embed safety controls including rate limiting, deduplication, suppressions, channel preference ordering, and compliance rules into the platform.
• Enhance data architecture and streaming pipelines to capture real-time delivery telemetry, reachability metrics, and per-message costs.
• Migrate active notification workloads from legacy systems to the core platform without downtime.
• Ensure high system availability and scale through monitoring, automated retries, idempotency controls, and traffic handling.
• Maintain regulatory compliance and recordkeeping for outbound messaging across international markets such as India and Brazil.
• Write clean, performant, and well-tested code following TDD practices with comprehensive test suites.
• Create clear technical documentation and onboarding materials for internal teams adopting the platform.
• Conduct code and design reviews while mentoring engineers on platform patterns and messaging best practices.

Skills

Backend engineering

Distributed systems

Messaging platforms

APIs

TDD

Kubernetes

AWS/GCP

Kafka

Data modeling

Code reviews

Education

Bachelor's degree in CS or equivalent

Tools

Twilio

Infobip

SendGrid

Git

Docker

Job description

PayJoy, Inc. is seeking a Senior Software Engineer for the Communications Platform to design and build a consolidated, reliable messaging system across SMS, email, and WhatsApp.

You will partner with Identity, Fraud, CDP, and Onboarding teams to deliver scalable, observable infrastructure. You will implement APIs with strong SLAs, drive multi-tenant data models, and ensure regulatory compliance across international markets while mentoring engineers and contributing to platform-wide technology