Twine
Freelance Developer – Fintech
TwineSingapore19 hours ago
ContractEngineering
Join a project focused on developing a Chrome extension that streamlines the process for users to download their KSeF certificate from a government portal and upload it securely to a fintech SaaS platform. This role is ideal for an experienced developer with a strong background in browser extension development, particularly for Chrome, and an understanding of secure file handling and REST API integration. The extension will guide users through a step-by-step process, ensure compliance with Chrome Web Store requirements, and provide clear user feedback throughout. You will play a key role in both the technical build and the successful publication of the extension.

Deliverables

  • Develop a fully functional Chrome extension using Manifest v3, JavaScript or TypeScript, and Chrome APIs.
  • Implement a guided workflow for users to download and upload KSeF certificates.
  • Integrate secure file detection, handling, and REST API communication for uploads.
  • Conduct validation checks and ensure GDPR compliance.
  • Provide user and technical handover documentation.
  • Assist with the Chrome Web Store submission process and address any compliance feedback.
  • Deliver clean, well-documented source code.

Requirements

  • Proven experience building and publishing Chrome extensions, including Manifest v3.
  • Proficiency in JavaScript or TypeScript and Chrome extension APIs.
  • Strong understanding of secure file handling and authentication flows.
  • Experience with REST API integration.
  • Familiarity with GDPR and Chrome Web Store compliance.
  • Ability to create clear user and technical documentation.
  • Experience with fintech, ERP, or e-invoicing systems (especially Polish KSeF) is a plus.
  • Available to start within 1–2 weeks and deliver within 2–4 weeks.
  • Excellent communication skills and attention to detail.

About Twine

Twine is a leading freelance marketplace connecting top freelancers, consultants, and contractors with companies needing creative and tech expertise. Trusted by Fortune 500 companies and innovative startups alike, Twine enables companies to scale their teams globally.

Our Mission

Twine's mission is to empower creators and businesses to thrive in an AI-driven, freelance-first world.

Key Skills

Ranked by relevance