Senior Fullstack Engineer — AWS Microservices & Integrations

We are looking to hire 2 individuals and will consider varying experience levels to fill both positions.

This is an in house position so the candidate must be located in Bristol and willing to work from the office the majority of the time.

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 Node.js/TypeScript (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.