First-hand case: how MySmartCoPilot is built

A visitor who converts a 50 MB phone video on MySmartCoPilot, the site this lesson is on, never uploads it: on the 75th-percentile connection in India the upload alone would take more than three minutes. The site is a full frontend and backend website, and its first rule is to put each piece of work where it is quickest and safest: on the visitor’s device when it can be, on the backend when it must be shared, kept or paid for.

The site’s real architecture has the pages and on-device tools in front; a PHP 8.4 backend behind Apache, with MariaDB in seven groups, scheduled jobs and an outbox, and an AI gateway; and the budgets it keeps.

The architecture in one picture

The pages are built ahead of time and served by Apache as files: a tool page, a lesson, and the scripts and styles they share. What a page does happens in the browser. Tools work on the visitor’s files there, and the site’s about page says that almost all of them do (About MySmartCoPilot). Behind /api/ runs a PHP 8.4 backend with MariaDB: accounts and sign-in, payments and licences, email through the host’s own mail service, Shop, Play and Learn services, and the AI gateway. The whole of it, from the device down:

Follow four requests through it, from a tool page to a question for the AI:

The program below prices what the design avoids: sending the visitor’s file to a server and the result back, on the 75th-percentile connection in India, which an annual study of device and network performance puts at 2.1 Mbit/s up and 6.2 Mbit/s down (The Performance Inequality Gap):

# Why heavy media work stays on the visitor's device: the time a server would need just to receive a file and send the
# result back, on the 75th-percentile connection in India (2.1 Mbit/s up, 6.2 Mbit/s down, the cited measurement).
# The result is assumed to be as large as the file. Worked on the device, the network time is 0.
UP_MBIT_S = 2.1
DOWN_MBIT_S = 6.2
FILES = (("photo", 5), ("phone video", 50), ("long video", 500))  # name, megabytes


def seconds(megabytes: float, mbit_s: float) -> float:
    return megabytes * 8 / mbit_s


print(f"{'file':<12}{'size':>7}{'upload':>9}{'download':>10}{'in all':>10}")
for name, size in FILES:
    up, down = seconds(size, UP_MBIT_S), seconds(size, DOWN_MBIT_S)
    total = up + down
    shown = f"{total / 60:.1f} min" if total >= 60 else f"{total:.0f} s"
    print(f"{name:<12}{f'{size} MB':>7}{f'{up:.0f} s':>9}{f'{down:.0f} s':>10}{shown:>10}")
print("on the device: 0 s on the network, and the file never leaves it")

file           size   upload  download    in all
photo          5 MB     19 s       6 s      25 s
phone video   50 MB    190 s      65 s   4.2 min
long video   500 MB   1905 s     645 s  42.5 min
on the device: 0 s on the network, and the file never leaves it

A photo costs 25 s of network time, a phone video 4.2 minutes and a long video 42.5 minutes before any server has done any work. On the device that time is zero, and the promise of each tool page, that files stay with their owner, holds by construction. The rest of the lesson takes each part apart; in one sentence each:

• On the device first: tools, code examples and on-device AI run in the browser, so files never travel.
• Separate originsorigin (web): The scheme, host and port of a web address, such as https://mysmartcopilot.com. Browsers keep each origin's storage and cookies apart, so a page on one origin cannot read another origin's data.: code a learner runs and the sign-in cookies each live on an origin of their own.
• Seven database groups: data is split by what one transaction changes together, and a group grows by adding a database.
• An outboxtransactional outbox: A table written in the same transaction as a change, holding the message that change must send. A separate job reads it and sends each message, so a message leaves only for a change that committed.: a change and the message it must send are written in one transaction, and a scheduled job sends it.
• Releases with a way back: the backend switches to a new release in one step, and back only when that is safe.
• No caps of its own: the AI gateway falls through to the next provider, and abuse protection takes the place of quotas.

On the device first: files, code and models that stay put Pro: opens with a Pro, Premium or Ultimate pass