About us
Climate & Decisions is a Sydney-based advisory firm founded in 2024 by former Deloitte and SAP leaders. It is a member of the Stone & Chalk innovation hub. We are building an enterprise software platform for large to medium organisations:
• Live in production on AWS. Enterprise customer onboarding starts in January 2027.
• Multi-tenant B2B SaaS. Each customer has an isolated environment.
• Independent engineering audit completed in October 2026. Its findings are your starting backlog.
• Stack: Python / FastAPI, PostgreSQL with row-level security, vanilla JavaScript, AWS (ECS Fargate, RDS, Bedrock, CloudFormation), GitHub Actions. We share product details after a mutual NDA.

What you'll do
before ChristmasBy early December the critical fixes are done and the platform goes through a penetration test. By Christmas the foundations are signed off by you, ready for customers in January.
• Review the code and the audit. Read the codebase and the independent engineering audit. Confirm, re-prioritise and own the fix plan.
• Be the reviewer on every change. Review and approve all pull requests before they reach production.
• Harden security. Check tenant isolation (row-level security, database roles), login and MFA, roles and permissions, secrets, and the guardrails around AI features.
• Make releases safe. Set up database migrations, a staging environment, deployment checks, monitoring and alarms, and backups with a tested restore.
• Add automated checks. Security and dependency scanning in CI, alongside the existing tests.
• Prepare for the penetration test. Get the platform ready for an external penetration test in early December 2026, then fix what it finds.
• Document it. Write a short incident runbook and the security answers enterprise customers ask for.
• Plan 2027. Deliver a prioritised engineering roadmap for the next 6 months. What you'll bringMust have
• 10+ years building and running production software, including multi-tenant B2B SaaS.




• Strong Python (FastAPI, Django or Flask) and PostgreSQL: row-level security, roles, migrations.
• AWS in production: ECS/Fargate, RDS, IAM, CloudFormation or similar infrastructure as code.
• Application security: OWASP Top 10, authentication and MFA, secrets management.
• CI/CD with GitHub Actions, and a disciplined pull-request review practice.
• Comfortable working with tools like Claude Code.
• Explains technical risks clearly to a non-technical founder.
• Right to work in Australia. Nice to have
• SOC 2 or ISO 27001 experience.
• Security of LLM features (prompt injection, data leakage), ideally on AWS Bedrock.
• Testing calculation-heavy or financial systems.
• Fractional CTO or technical advisor experience with startups building scalable SaaS solutions. Beyond ChristmasThere is a explicit opportunity to continue part time in 2027, at about 1 day a week, as the platform's trusted technical owner.
• Remain the required reviewer on code changes and the security owner.
• Oversee the penetration retest and any remaining fixes.
• Run quarterly backup-restore drills and dependency and security reviews.
• Give architecture guidance and light-touch review of a junior developer's work.
• Be on call as backup during customer go-lives. As enterprise customers sign, the role can grow to 2–3 days a week or a fractional technical lead position. Terms and

how to apply
• Start: as soon as possible in November 2026.
• Rate: A$1,100–1,300 per day + GST, ABN contract, depending on experience.
• Before access: mutual NDA and IP assignment for work delivered.
• Working pattern: flexible days, with some overlap with Sydney business hours. To apply, email [email protected] with the subject "Senior Software Engineer" and include:
• Your CV or LinkedIn profile.
• One paragraph on a SaaS security or code review you led, and what you found.
• Your availability (days a week, from when) and your expected day rate within this range.

📌 Senior Software Engineer (Sydney)
🏢 Climate & Decisions
📍 Sydney