Flutter/Dart+Rust (P2P Networking) Engineer Debug & First Deployment of Existing Codebase (NDA req)

Job Title Flutter/Dart + Rust (P2P Networking) Engineer — Debug & First Deployment of Existing Codebase (NDA Required) Category Mobile App Development → Flutter Project Description I'm the founder of an early-stage mobile communications app — Flutter/Dart front end with a Rust-based peer-to-peer networking core (compiled via FFI). The codebase is substantial and mature in design (tens of thousands of lines across both languages, built out over many structured development phases covering messaging, calling, group collaboration features, and account security), but it has not yet been through a full first compile-and-deploy cycle. I'm running the build through CI and have been steadily clearing real issues myself — dependency conflicts, a couple of networking-library API mismatches, lint/analyzer failures. Progress so far suggests normal first-integration friction on a large codebase, not a fundamentally broken design. What I need: an engineer to take this from “clearing static analysis issues” through to a genuinely working, installable debug build on Android, with a second phase on iOS/Apple once Android is solid. Confidentiality is a hard requirement for this engagement. Project name, full architecture, and complete feature scope will only be shared after a signed NDA (I can provide mine, or use Upwork's standard NDA feature). Please do not ask for repo access or detailed specifics in your proposal before that's in place — I'll share what's needed once we're under NDA. Scope of Work - Resolve remaining static-analysis and test failures in the current build pipeline (I'll walk you through the current error log directly). - Get a clean debug Android build ("flutter build apk --debug" or equivalent) succeeding in CI. - Install and manually validate the resulting build on a real device or emulator — core flows (identity setup, basic messaging) should run without crashing. - Extend the same process to the iOS/Apple build path. - Document fixes with brief rationale as you go — I'm tracking this closely and want to understand root causes, not receive silent patches. - Clearly flag anything that looks like a genuine logic, security, or architectural concern — versus routine dependency/import fixes — rather than silently altering behavior. Tech Stack (General; details under NDA) - Flutter/Dart (recent stable channel) - Rust via FFI, cross-compiled for mobile targets - A modular peer-to-peer networking library (specifics shared under NDA) - WebRTC-based real-time media - CI-based build pipeline (GitHub Actions) Ideal Candidate - Strong, demonstrable Flutter/Dart debugging experience on existing, non-trivial codebases — not a from-scratch builder - Real Rust experience; comfort with FFI and cross-compilation toolchains (NDK, etc.) - Familiarity with peer-to-peer/distributed networking concepts (happy to assess this in interview without disclosing proprietary specifics upfront) - Professional discretion as standard practice — comfortable working under NDA and not discussing client projects publicly Deliverables - Signed NDA before repo access or full technical disclosure - Clean CI build producing a working, installable Android debug artifact - iOS/Apple build reaching a working state - Brief written notes on substantive fixes made - Clear separation of “routine fix” vs. “flagged for founder decision” issues Engagement Structure Milestone-based: - Milestone 1 — 10%: NDA, repository intake, failure reproduction, and diagnostic report Milestone 2 — 15%: Flutter/Dart analyzer and test stabilization Milestone 3 — 20%: Reproducible Android CI build and installable debug artifact Milestone 4 — 20%: Android device validation and core-flow stabilization Milestone 5 — 15%: Reproducible iOS/Apple build Milestone 6 — 15%: iOS device or simulator validation Milestone 7 — 5%: Final documentation, handover, and correction period Application Instructions Please do not include speculative guesses about the project, its name, or its purpose in your proposal; this will not be held against you, but specifics will only be discussed after NDA. Instead, focus your proposal on: - Relevant Flutter/Dart debugging experience - Rust/FFI/cross-compilation experience - Any P2P/distributed-systems work you've done Names of past projects are fine. No need to disclose those clients' confidential details either — mutual professionalism.