TaskFlow Target Authentication Architecture Define exactly how Supabase Auth, Next.js, NestJS, and business authorization will divide responsibilities
Phase 16 - Authentication Fundamentals Volume 05 - Authentication & Security
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Phase 16 builds the security mental model before any Supabase Auth integration code is introduced.
TaskFlow target architecture before implementation We now have enough vocabulary to describe the security architecture Phase 17 will implement. Supabase Auth will establish identity. Next.js will manage the web session boundary. NestJS will trust only tokens it verifies according to the expected issuer/key/claims. Business services will receive a trusted user identity, not an arbitrary userId from the request body.
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Phase 17 implements the provider integration; Phase 18 implements the API guard in detail.
Identity should enter the service as trusted context // Future direction - conceptual only
createTask(authenticatedUser, dto)
// NOT: createTask(dtoWithUserIdChosenByBrowser)
Separate identity provider ID from domain records An authentication provider subject identifies an authenticated principal. Your application may also maintain a domain User/Profile record for business data. The relationship must be explicit; do not assume every auth claim should be copied directly into every business table.
The browser, Next.js, NestJS, and Supabase each have different responsibilities. Do not implement four separate password/login systems.
TaskFlow Target Authentication Architecture matters because it changes a real boundary in TaskFlow. The goal is to understand the inputs, owner, observable output, and failure modes before adding more abstraction.
Restate the goal of “TaskFlow Target Authentication Architecture” as one observable behavior. Write the success signal before touching code.
Trace the boundary map: User intent → UI boundary → API contract → business rule → persistence → observable result. Mark the one boundary this lesson changes.
Inspect the current repository state and record the exact files, route, table, or runtime involved. Avoid creating an abstraction before you can name the existing owner.
Implement the smallest vertical slice. Add one coherent change, run the narrowest verification command, and read the output before continuing.
Connect the slice to TaskFlow’s phase artifact: Authentication threat/flow diagram explaining what the browser stores, what servers verify, and what happens when credentials expire.. Verify behavior from the outside as a user or API client would.
Create one controlled failure that is safe to reproduce. Predict the symptom first, capture evidence, locate the earliest broken boundary, then fix only that cause.
Close the reference and rebuild or explain the core change from memory. Record what you would monitor or test before trusting the same change in production.
Input -> owner -> transformation -> observable output -> failure evidenceDo not copy this as a finished answer. Predict what each boundary does, type the smallest useful slice, run it, then compare the result with your prediction.
Return to the nearest observable boundary: input, network, process log, database, or rendered UI. Compare actual evidence with the predicted path.
Change one variable at a time and reproduce the original failure after the fix; otherwise you have correlation, not diagnosis.
Without copying the final source, create a second small scenario that applies “TaskFlow Target Authentication Architecture” to a different TaskFlow resource or input. Write the acceptance criteria first, implement it, and provide the evidence that each criterion is satisfied.
Compare opaque sessions and JWT access tokens by state, revocation, and verification model.
Use the smallest change that demonstrates this lesson. Stop after it works and capture evidence.No plan for expired/revoked sessions
Predict the symptom before causing the failure. Then locate the earliest boundary where reality diverges from expectation.Why does this responsibility live here, what input does it trust, what output proves success, and what would go wrong if another layer owned it?
If your explanation is vague, repeat the boundary trace before moving on.Close the reference. Reproduce the core idea from memory or explain the exact request/data flow aloud. Then check your diff or notes for accidental shortcuts that bypass validation, authorization, error handling, or verification earned in earlier phases.