# Mini Apps SDK docs — MainButton and BackButton

## Metadata

| Field | Value |
|---|---|
| Institute | Molodetz Institute — Research & Retrieval Division |
| Subject | tui-framework-design |
| Document type | Source Dossier |
| Tier | 1 |
| Source title | Main Button documentation (Telegram Mini Apps SDK docs) |
| Source URL | https://docs.telegram-mini-apps.com/platform/main-button |
| Source publisher / author | Telegram Mini Apps community (docs.telegram-mini-apps.com, over the official protocol) |
| Source type | vendor docs |
| Source date (published) | Unknown — not stated |
| Date researched | 2026-10-11 |
| Researched by | tai (agent), model: Muse Spark, on behalf of retoor |
| Research method | direct page fetch |
| Confidence | Medium |
| Status | Active |

## Summary

Community SDK documentation for the two primary Mini App buttons: the bottom full-width MainButton reserved for the final action (with text, active, progress, and color control), and the header BackButton, which carries visibility and click plumbing but deliberately no built-in navigation action.

## Key findings

- MainButton is a bottom full-width call-to-action for the final action, supporting text, active/disabled state, progress loader, and colors; for attachment-menu launches it stays hidden until the user interacts.
- The class was renamed BottomButton with a SecondaryButton stacked above it, keeping the same bottom-CTA role.
- BackButton is a header-left chevron with show/hide/onClick control and no built-in action: the developer handles every press.

## Pros / strengths

- Precise behavioral detail (hidden-until-interact, no-built-in-nav) that the official page states more tersely.
- Documents the current BottomButton/SecondaryButton shape, not just the legacy MainButton name.

## Cons / limitations / caveats

- Community docs over the official protocol: may lag or drift from Telegram's own reference, so load-bearing behavior wants official corroboration.
- The sibling back-button page was listed as consulted but no evidence from it was captured, so it is not archived here (open gap).

## Relevance to tai

Shapes tai's action-button grammar: one bottom primary action with active/progress states, a header back control with no implicit behavior, and hidden-until-relevant discipline for contextual actions.

## Changelog

| Date | Change |
|---|---|
| 2026-10-11 | Initial dossier created. |