Senior Fullstack Engineer — AWS Microservices & Integrations
We are looking to hire 2 individuals and will consider varying experience levels to fill both positions.
Salary: £50k - £80k+ depending on experience
Mission:
Own our microservices platform on AWS. Build reliable, multi-tenant services and a
first-class integrations layer (messaging, outreach, CRM/billing, analytics, and payment
systems) that powers a SaaS product at scale.
What you'll do:
• Design & build microservices behind API Gateway (REST/HTTP), running on
Lambda and/or containerized workloads on EC2/Fargate.
• Model multi-tenant data across DynamoDB and RDS (PostgreSQL), using S3 for
object storage and KMS for secrets/encryption.
• Integrations layer: OAuth/API-key onboarding, webhook ingestion (idempotency,
retries, DLQs), rate-limit mediation, circuit breakers, and versioned connector
contracts.
• Integrate with 3rd-party platforms and payment systems, ensuring secure,
reliable, and scalable flows for transactions, billing, and data exchange.
• Event-driven architecture: Publish/consume domain events via
SQS/SNS/EventBridge; use Step Functions where orchestration helps.
• Observability & reliability: Structured logging, metrics, and alerts with
CloudWatch; trace propagation; error budgets and SLOs.
• Security by default: Least-privilege IAM, secret rotation, per-tenant isolation, audit
logs.
• IaC & CI/CD: Define everything in AWS SAM, ship via GitHub Actions with
automated tests, canary/blue-green where appropriate.
• Collaboration: Define crisp API contracts with Frontend & AI services; document
runbooks and postmortems.
Must-have prerequisites:
• 4+ years operating on AWS with meaningful DevOps ownership (you've shipped
and run production systems).
• Hands-on with: Lambda, EC2/Fargate, API Gateway, S3, DynamoDB, RDS
(Postgres), SQS/SNS/EventBridge, CloudWatch, KMS.
• Infrastructure as Code with AWS SAM (templates, pipelines,
parameterized/staged stacks).
• CI/CD with GitHub Actions (workflows, artifacts, environment gates) and
automated testing (unit/integration/contract; e.g., Jest/Vitest, Postman/Newman,
Pact).
• Strong backend development in (Go or Python also welcome)
and API design (REST; GraphQL a plus).
• Data modeling chops (NoSQL vs relational trade-offs, partitioning/indices,
migration strategies).
• Proven experience building/consuming webhook-heavy 3rd-party integrations
with idempotency and signature verification.
• Experience integrating with payment gateways (e.g., Stripe, Adyen, Braintree) and
handling PCI/DSS-compliant transaction flows.
Nice to have:
• Event choreography with Step Functions, schema registries, and outbox patterns.
• OpenTelemetry/X-Ray tracing; cost/perf tuning for Lambda and RDS.
• Auth: Cognito/OIDC, RBAC/ABAC, multi-tenant isolation patterns.
• Experience with real-time delivery (WebSockets/SSE) and streaming responses.
• Background in building connector SDKs or marketplaces.
Experience:
We are looking for someone who has designed, built, and operated production systems at
scale in AWS, ideally in a SaaS or integration-heavy environment. You should be
comfortable owning a service end-to-end — from infrastructure definition through
deployment pipelines to live operations — and confident integrating with external APIs,
payment gateways, and event-driven workflows.