Many small MVP projects run into delays because three areas receive too little attention during initial scoping: authentication, payments, and email. Each seems simple on the surface yet quickly expands once real requirements appear. A clear checklist helps keep the scope realistic without adding unnecessary features.
Founders often list core user actions first and treat supporting systems as afterthoughts. This leads to incomplete estimates and later surprises. The goal is to list concrete tasks for each supporting system before development begins.
List core user actions first
Begin by writing every action a user must complete to reach the main value of the product. Keep the list short and focused on the single problem the MVP solves. Avoid adding nice-to-have steps at this stage.
Once the primary flow is written, note any points where a user must prove identity, make a payment, or receive confirmation. These points become the anchors for the next sections of the checklist.
Define authentication needs
Decide what level of identity verification the MVP actually requires. Simple email and password may suffice for early testing. Social logins add convenience but introduce extra configuration and data handling.
Consider password reset flows, session duration, and whether any data must remain private between users. Each of these choices affects database tables, API endpoints, and error handling that must be built and tested.
If the product later needs roles or team access, note that requirement now even if it stays unused in the first version. Adding roles after launch usually requires more rework than adding them during the initial build.
Map payment steps
Identify every place money changes hands. This includes one-time purchases, subscriptions, refunds, and failed payment retries. Each case needs its own user interface and backend logic.
Choose a payment provider early and review its documentation for required fields, webhook events, and test modes. Integration usually involves more than a single button: it touches user records, order history, and notification systems.
Account for compliance items such as storing minimal card data and handling tax receipts if they apply to the target users. These tasks often take longer than the payment flow itself.
Plan email and notifications
List every email or in-app message the MVP must send. Include account creation, password resets, payment confirmations, and any reminders. Each message needs both a template and a trigger condition.
Decide whether transactional emails will use a dedicated service or the application server. A separate service reduces deliverability problems but adds another integration point to configure and monitor.
Test that emails reach inboxes during development rather than assuming the provider will handle everything. Include a way to view sent messages in an admin area so support staff can answer user questions without checking external dashboards.
Combine items into one checklist
After working through the three areas, return to the original user actions and attach the supporting tasks to each step. The resulting document shows the true size of the MVP before any code is written.
Review the checklist with anyone who will estimate time or budget. Adjust scope only by removing entire user actions, not by trimming supporting systems. This keeps the delivered product functional from day one.
Tbilisi Software uses a similar checklist when helping teams define early versions of their products.