Guided Course · Phases 26–27

Realtime, Storage & Collaboration

Add collaboration without confusing server truth, cache state, realtime events, and storage authorization.

Track project: Build Collaborative Tasks and Attachments. Finish the lessons, then close the transcript and build the project using evidence instead of copy-paste. Open project →

Realtime Event Model

Here’s the simple reason this matters: Realtime sends change notifications after data changes. The event is a signal that client state may need reconciliation; it should not automatically become a second source of truth. In this course, we connect it directly to realtime collaboration and file-storage behavior across multiple TaskFlow clients, so you can see where the idea lives in a real project instead of memorizing a definition.

≈ 1867 words 02

Two-Browser Realtime Lab

Here’s the simple reason this matters: This lesson is about Two-Browser Realtime Lab. Keep the idea practical: in realtime collaboration and file storage, the worked example should show that two independent clients converge on the same durable task state without manual refresh. Once you can explain why that happens, the name is much easier to remember. We connect it to the course project so you can see the idea working instead of memorizing a definition.

≈ 1947 words 03

Insert Events

Here’s the simple reason this matters: This lesson is about Insert Events. Keep the idea practical: in realtime collaboration and file storage, the worked example should show that an inserted row signals that active task-list data may need reconciliation. Once you can explain why that happens, the name is much easier to remember. We connect it to the course project so you can see the idea working instead of memorizing a definition.

≈ 1885 words 04

Update Events

Here’s the simple reason this matters: This lesson is about Update Events. Keep the idea practical: in realtime collaboration and file storage, the worked example should show that a known updated row can update an exact cached detail when payload shape and authorization assumptions are valid. Once you can explain why that happens, the name is much easier to remember. We connect it to the course project so you can see the idea working instead of memorizing a definition.

≈ 1938 words 05

Delete Events

Here’s the simple reason this matters: This lesson is about Delete Events. Keep the idea practical: in realtime collaboration and file storage, the worked example should show that deleted-resource detail cache is removed and list caches can be invalidated/refetched. Once you can explain why that happens, the name is much easier to remember. We connect it to the course project so you can see the idea working instead of memorizing a definition.

≈ 1895 words 06

Duplicate Event Reconciliation

Here’s the simple reason this matters: This lesson is about Duplicate Event Reconciliation. Keep the idea practical: in realtime collaboration and file storage, the worked example should show that an event identifier or idempotent reconciliation rule prevents duplicate delivery from applying the same side effect twice. Once you can explain why that happens, the name is much easier to remember. We connect it to the course project so you can see the idea working instead of memorizing a definition.

≈ 1972 words 07

Out-of-Order Events

Here’s the simple reason this matters: Out-of-order events happen when messages arrive in a different order from the writes that produced them. Correctness needs versions, timestamps, refetching, or another reconciliation rule. In this course, we connect it directly to realtime collaboration and file-storage behavior across multiple TaskFlow clients, so you can see where the idea lives in a real project instead of memorizing a definition.

≈ 1813 words 08

Reconnect Strategy

Here’s the simple reason this matters: This lesson is about Reconnect Strategy. Keep the idea practical: in realtime collaboration and file storage, the worked example should show that after a gap, the client refreshes durable state rather than assuming no events were missed. Once you can explain why that happens, the name is much easier to remember. We connect it to the course project so you can see the idea working instead of memorizing a definition.

≈ 1911 words 09

Realtime + TanStack Query

Here’s the simple reason this matters: This lesson is about Realtime + TanStack Query. Keep the idea practical: in realtime collaboration and file storage, the worked example should show that realtime becomes a freshness signal for the existing query cache instead of a parallel state store. Once you can explain why that happens, the name is much easier to remember. We connect it to the course project so you can see the idea working instead of memorizing a definition.

≈ 1950 words 10

Storage Mental Model

Here’s the simple reason this matters: This lesson is about Storage Mental Model. Keep the idea practical: in realtime collaboration and file storage, the worked example should show that the binary object and application metadata are separate resources with separate authorization/lifecycle concerns. Once you can explain why that happens, the name is much easier to remember. We connect it to the course project so you can see the idea working instead of memorizing a definition.

≈ 1946 words 11

File Upload Flow

Here’s the simple reason this matters: A file upload crosses several trust boundaries: browser selection, metadata validation, storage authorization, object upload, database metadata, and later download authorization. In this course, we connect it directly to realtime collaboration and file-storage behavior across multiple TaskFlow clients, so you can see where the idea lives in a real project instead of memorizing a definition.

≈ 1863 words 12

File Metadata

Here’s the simple reason this matters: This lesson is about File Metadata. Keep the idea practical: in realtime collaboration and file storage, the worked example should show that database metadata records ownership and business context without storing raw binary data in ordinary application rows. Once you can explain why that happens, the name is much easier to remember. We connect it to the course project so you can see the idea working instead of memorizing a definition.

≈ 1922 words 13

Authorized Download

Here’s the simple reason this matters: This lesson is about Authorized Download. Keep the idea practical: in realtime collaboration and file storage, the worked example should show that a signed URL is created only after server-side authorization on the attachment’s owning resource/tenant. Once you can explain why that happens, the name is much easier to remember. We connect it to the course project so you can see the idea working instead of memorizing a definition.

≈ 1918 words 14

Unsafe Upload Lab

Here’s the simple reason this matters: This lesson is about Unsafe Upload Lab. Keep the idea practical: in realtime collaboration and file storage, the worked example should show that the server/storage policy rejects or normalizes untrusted metadata and never trusts the browser-provided filename/path as authorization. Once you can explain why that happens, the name is much easier to remember. We connect it to the course project so you can see the idea working instead of memorizing a definition.

≈ 1974 words 15

Delete File Lifecycle

Here’s the simple reason this matters: This lesson is about Delete File Lifecycle. Keep the idea practical: in realtime collaboration and file storage, the worked example should show that deletion is treated as a multi-resource workflow with a recoverable partial-failure plan. Once you can explain why that happens, the name is much easier to remember. We connect it to the course project so you can see the idea working instead of memorizing a definition.

≈ 1929 words 16

Build Collaborative Task Attachments

Here’s the simple reason this matters: This lesson is about Build Collaborative Task Attachments. Keep the idea practical: in realtime collaboration and file storage, the worked example should show that the feature joins forms, API authorization, storage, database metadata, realtime, cache reconciliation, and lifecycle cleanup. Once you can explain why that happens, the name is much easier to remember. We connect it to the course project so you can see the idea working instead of memorizing a definition.

≈ 1992 words

Track knowledge check

Check the mental models before the project

Answer from memory. If two options sound similar, explain the boundary difference before choosing.

01Which statement best explains “Realtime Event Model” in this track?

02Which statement best explains “Two-Browser Realtime Lab” in this track?

03Which statement best explains “Insert Events” in this track?

04Which statement best explains “Update Events” in this track?

05Which statement best explains “Delete Events” in this track?

06Which statement best explains “Duplicate Event Reconciliation” in this track?

07Which statement best explains “Out-of-Order Events” in this track?

08Which statement best explains “Reconnect Strategy” in this track?

09Which statement best explains “Realtime + TanStack Query” in this track?

10Which statement best explains “Storage Mental Model” in this track?