software engineer / technical consultant

Sdu Gumede

Johannesburg, South Africa[email protected]sduu.devgithub.com/sduduzog

## experience

Daemon

Consultant

JWO (Just Walk Out) Daemon

  • Building the Go connector between POS providers and Amazon’s Just Walk Out platform.
  • Implemented providers for Oracle Simphony, Shopify and Clover Sport.

AJ Bell Daemon

  • Evaluated Hangfire, Quartz.NET, Elsa, Temporal and WorkflowCore; recommended WorkflowCore for the existing AWS and MongoDB stack.
  • Built the proof of concept, initial API endpoints and hosted workflows for a pension-payout case-management service.
  • The production service reduced a multi-day manual process to as little as one day when no manual intervention was required.
  • Introduced a Playwright builder pattern for deterministic test data, removing failures caused by shared and duplicate setup data.

Domestic & General Daemon

  • Introduced Drizzle ORM, composable database connections and Drizzle-managed schema migrations for TypeScript services on AWS Lambda.
  • Added isolated unit-testing patterns for Lambda handlers and services, plus shared Zod validation schemas.
  • Modernised ESLint configuration in a shared repository used across the team’s services.
  • Identified PostgreSQL connection exhaustion and documented the data-access patterns and pooling options for the team.

Codeo

Software Engineer

Yumbi / Famous Brands Codeo

  • Built and maintained the React Native Android application around a Vue.js food-ordering platform.
  • Added AWS SNS push notifications, deep links and native modules, and managed Google Play releases.
  • Modernised the AngularJS back office build, introduced Jest and TypeScript, and implemented dynamic RBAC scoped by store, brand and region.

Spar Codeo

  • Worked on the React Native application wrapping the AngularJS frontend for Spar Rewards.
  • Built .NET sagas and workflows for ordering, campaigns, promotions and vouchers across the Spar and Yumbi platforms.

Backend infrastructure Codeo

  • Worked with Codeo’s in-house .NET orchestration framework across the Yumbi and Spar backends.
  • Contributed to migrating services to a Nomad container cluster with Consul service discovery.
Sdu Gumede[email protected] · sduu.dev02 / 02

## technical work

Backend services Go · C#/.NET · Node.js · Elixir

Built Go POS providers for JWO, .NET APIs and hosted services for AJ Bell, and TypeScript Lambda services for Domestic & General. Additional backend experience includes Node.js and Phoenix/Elixir.

Workflow orchestration WorkflowCore · .NET sagas

Built AJ Bell’s pension-payout workflows with WorkflowCore and Codeo sagas covering ordering, campaigns, promotions and vouchers for the Yumbi and Spar platforms.

Mobile applications Kotlin · Android · React Native

Worked on the Yumbi/Famous Brands and Spar applications, including push notifications, deep links, native modules, analytics and Google Play releases. Built Slim Launcher with Kotlin and Jetpack Compose.

Web applications Vue · Nuxt · TypeScript · AngularJS

Worked on Yumbi’s Vue ordering application and AngularJS back office, including its TypeScript and Jest migration. Additional frontend work includes Nuxt applications and reusable libraries.

Integrations GraphQL · REST · OAuth2 PKCE

Built reusable provider integrations and the JWO connectors for Oracle Simphony, Shopify and Clover Sport. Wrote configuration documentation and added readiness checks for provider work.

Access control & validation RBAC · Zod · TypeScript

Implemented dynamic permissions scoped by store, brand and region for Yumbi. Added shared Zod schemas and generated types for Domestic & General services.

Application releases & production APIs Android · AWS Lambda

Managed Yumbi’s Android releases to Google Play, published and maintained Slim Launcher, and overhauled Yumbi’s back-office build system. At Domestic & General, implemented APIs that had previously been mocked; the concrete implementations were deployed to production after unit and manual testing.

## tools & infrastructure

01 / data

Databases

PostgreSQL, MySQL and MongoDB. Drizzle ORM, schema migrations, reusable connections and connection-pooling work.

02 / cloud

AWS & infrastructure

AWS Lambda, SNS and RDS; AWS CDK, Terraform, Nomad and Consul.

03 / quality

Testing

Playwright, Jest and TDD; deterministic test-data builders and isolated handler and service tests.