THE VIDEO LIBRARY

See how it works.
Know what to check.

One full training, a quick overview and three focused lessons. Choose a starting point, then put one idea to work.

Videos open on YouTube. No embedded YouTube player, remote thumbnail or tracking script loads here. The training uses AI narration.

A PRACTICAL WAY TO LEARN

Read a system. Ask better questions.

You do not need to memorize every tool name. Follow the path from a person’s request to stored data, then check who can act, what can fail and how recovery works.

Understand the request

Trace the frontend, APIs, services and data. Learn why retries need safeguards, why cached data needs boundaries and why each service must check permissions.

Protect access and information

Compare password defenses, safer SQL queries and delegated access. Separate OAuth permissions from sign-in, and keep AI tools within approved data and action limits.

Plan for changes and failures

Distinguish payment approval from settlement. Review notifications, backups, tests and release gates. Historical company examples illustrate trade-offs; they are not a current infrastructure audit.

Browse all 18 chapters

Each link opens the full training on YouTube at the listed chapter.

  1. 00:00Start with the three-layer map
  2. 01:01APIs and reliable requests
  3. 03:27API performance
  4. 04:35Architecture patterns
  5. 06:49Password attacks and layered defenses
  6. 09:29SQL and safer queries
  7. 11:04OAuth delegated access and OpenID Connect
  8. 13:04Cloud services and permissions
  9. 14:11Diagram-as-code
  10. 15:08Notification decisions
  11. 16:10Data platforms and access
  12. 17:05Card authorization, clearing and settlement
  13. 18:38Historical Twitter and Netflix examples
  14. 20:11How a ChatGPT-like system works
  15. 22:08Payment fees and reconciliation
  16. 23:20Nine types of API testing
  17. 24:25Shipping code safely
  18. 25:19Put the system map to work

Topic inspiration: ByteByteGo’s system-design material. The explanations and diagrams in this training are original. No endorsement is implied.

Explore the video library

Have a few minutes? Start with the 2:31 overview, then choose a short lesson. Each one links to a practical security check.

2:31 OVERVIEW

How Real Systems Work: A Practical Security Overview

A concise security-first map of everyday applications: APIs, password defenses, parameterized queries, OAuth versus OpenID Connect, limited tokens and specific checks at trust boundaries.

Watch on YouTube

Read the full security baseline

SHORT LESSON

Six Password Attacks: Why Layered Defenses Matter

Six common ways attackers target account access, and why authentication, recovery, device protection and monitoring belong together. Layered controls reduce risk; no stack guarantees every attack will fail.

Watch on YouTube

Check account security

SHORT LESSON

What Happens After You Tap Buy?

Follow one illustrative app request through frontend, APIs and data services, then ask what each trust boundary must check. Real architectures and timings vary.

Watch on YouTube

Read the website security baseline

SHORT LESSON

Card Payments: Approval Is Not Settlement

Authorization, clearing and settlement are different parts of a card payment. Refunds, reversals and chargebacks can still create obligations after settlement. This is a simplified educational model, not payment-provider or legal advice.

Watch on YouTube

Review payment safeguards

Videos open on YouTube. No YouTube player or remote media loads on this page.

AFTER YOU WATCH

Choose one improvement you can verify.

Use an application you own or are authorized to administer. Keep passwords, recovery codes and private customer records out of your notes.

  1. Draw one request

    Pick a familiar action, such as placing an order. Write down the screen, service and stored records involved.

  2. Mark access and approvals

    Identify who can read or change each record. Note where a payment, account change or AI action needs an authorized review.

  3. Check failure and recovery

    Ask what happens if a request repeats, a service stops or an account is lost. Verify a backup by restoring a harmless sample.

  4. Assign the next check

    Record one gap, the person responsible and how you will verify the fix. Return to the self-check when the change is complete.

Use the self-check to pick a starting point