--- title: "Fitness app build plan and PRD generator" canonical: "https://aifitnessapi.com/tools/build-plan" markdown: "https://aifitnessapi.com/tools/build-plan.md" type: "tool" last_reviewed: "2026-11-05" description: "Pick an app type, platforms, data sources and features; get a shareable build plan and a PRD template from sourced pages: APIs, compliance, cost shape." publisher: "AIFitnessAPI — funded by KinesteX; first-party pages disclose it" cite_as: "\"Fitness app build plan and PRD generator\", AIFitnessAPI, https://aifitnessapi.com/tools/build-plan" --- # Fitness app build plan and PRD generator > Pick the app type, platforms, data sources and features, and this generator writes a build plan you can share as a link or download as Markdown: an architecture outline linking the page that covers each layer, the products from this site's cost model that fit, the cost shape (how each product bills and our labeled effort judgment, never a price), the health-data rules your answers point to, and the store-review items that apply. The same answers fill a PRD template that quotes Apple's and Google's documentation on edge cases such as HealthKit read denial and Health Connect's 30-day read window. It is a starting plan, not legal advice. - Canonical: https://aifitnessapi.com/tools/build-plan - Last reviewed: 2026-11-05 - Publisher: AIFitnessAPI (https://aifitnessapi.com) - Cite as: "Fitness app build plan and PRD generator", AIFitnessAPI, https://aifitnessapi.com/tools/build-plan --- *[Interactive: the build-plan form, the generated plan, and the spec and PRD downloads, in the browser at https://aifitnessapi.com/tools/build-plan; not reproduced in this mirror.]* ## Where each part of the plan comes from - App types and health data types: the [build guides](https://aifitnessapi.com/build) and the concrete stack each one names, joined to Apple's identifier dataset and, for Android, only to pairs both platforms' documentation confirms. - Products and the cost shape: the provenance-tracked model behind the [cost planner](https://aifitnessapi.com/cost-planner) and the [API directory](https://aifitnessapi.com/apis), which records how each product bills, what each user must own and which approval gates a launch, and states no prices. - Compliance: the quoted rules of the [compliance wizard](https://aifitnessapi.com/tools/compliance-wizard), routed from your answers. - Store review: the items of the [store submission checklist](https://aifitnessapi.com/tools/store-submission-checklist) that your platforms and features trigger. - Architecture: one line per layer, each linking the page on this site that covers it, from on-device sync to deletion and export. ## What it will not do It will not price the plan. The cost model behind it holds no dollar figures, because most serious tiers in this market are contact-sales and public prices move; the plan groups products by how they bill and gives the span of our effort judgment (low is roughly days, medium roughly weeks, high roughly months), labeled as ours. It will not rank. Products the build guide for your app type already names sort first, then by how they bill; nothing is scored. KinesteX, which funds this site, appears only in a plan that includes camera motion tracking, and then with the disclosure beside it. It will not decide your legal position. The compliance section is a routing from your answers to rules quoted from their sources; the [compliance wizard](https://aifitnessapi.com/tools/compliance-wizard) asks the questions that settle HIPAA status, and a qualified professional should confirm the result. ## The edge cases the PRD template quotes The PRD's edge-case section quotes the platforms' own documentation for the platforms you pick, read on November 5, 2026: - [A denied HealthKit read looks exactly like no data](https://aifitnessapi.com/fix/healthkit-authorization-denied): “To help prevent possible leaks of sensitive health information, your app cannot determine whether or not a user has granted permission to read data. If you are not given permission, it simply appears as if there is no data of the requested type in the HealthKit store.” (Apple, authorizationStatus(for:)) - [Health Connect reads stop at 30 days before the first grant](https://aifitnessapi.com/fix/health-connect-no-data): “By default, all applications can read data from Health Connect for up to 30 days prior to when any permission was first granted.” (Android Developers, Read raw data (Health Connect)) - [Older history needs its own permission](https://aifitnessapi.com/architecture/historical-backfill): “Otherwise, without this permission, an attempt to read records older than 30 days results in an error.” (Android Developers, Read raw data (Health Connect)) - [An unused Health Connect changes token expires](https://aifitnessapi.com/fix/health-connect-changes-token-expired): “Since an unused Changes token expires within 30 days, you must use a sync strategy that avoids losing information in such a case.” (Android Developers, Synchronize data (Health Connect)) - [Google Fit is not a foundation to build on](https://aifitnessapi.com/google-fit-shutdown): “The Google Fit API (including the REST API) will only be supported until the end of 2026.” (Android Developers, Google Fit migration guide) ## Related planners For the stack alone, the [stack generator](https://aifitnessapi.com/tools/stack-generator) narrows a build guide's products with four questions. For a starting recommendation before you know the app type, the [API picker](https://aifitnessapi.com/picker) asks three. If you would rather not write code, the [no-code fitness app guide](https://aifitnessapi.com/no-code-fitness-app) covers the builder platforms. A free tool from AIFitnessAPI. More at [free tools for health-app builders](https://aifitnessapi.com/tools). ## Next step Turning this into a choice of API: - [Native vs Cross-Platform, Firebase vs Supabase: Choosing a Fitness App Tech Stack](https://aifitnessapi.com/build/fitness-app-tech-stack) - [The Best Wearable Fitness & Health-Data APIs (2026)](https://aifitnessapi.com/fitness-apis/wearable-data-apis) - [How Much Does a Fitness API Cost?](https://aifitnessapi.com/pricing/how-much-does-a-fitness-api-cost)