Lesson 3. JSON — Data Format#
Why This Matters#
JSON (JavaScript Object Notation) is the format services use to exchange data. Understanding JSON helps you read logs, debug integrations, and understand what happens "under the hood".
Key Idea#
JSON = structured data as "key: value" pairs
It's like a filled-out form: there are fields (keys) and answers (values).
What JSON Looks Like#
Simple example:
{
"name": "Ivan",
"phone": "+7-999-111-22-33",
"service": "Haircut"
}
Breakdown:
-
"name"— key (field name) -
"Ivan"— value -
"phone"— key -
"+7-999-111-22-33"— value
JSON with Multiple Objects#
Example: list of clients
{
"clients": [
{
"name": "Ivan",
"phone": "+7-999-111-22-33"
},
{
"name": "Maria",
"phone": "+7-999-222-33-44"
}
]
}
Breakdown:
-
"clients"— array (list) of clients -
Each client is an object with
nameandphonefields
JSON in Integrations#
Scenario: AI agent sends data to CRM
Agent request (JSON):
{
"client_name": "Alexander",
"client_phone": "+7-999-333-44-55",
"lead_status": "Hot",
"budget": "200,000 rubles",
"comment": "Wants a website, urgent"
}
The CRM receives this JSON, reads the fields, and creates a client record.
How to Read JSON#
Rules:
-
{}— object (one set of data) -
[]— array (list of objects) -
"key": "value"— key-value pair -
,— separator between fields
Practice example:
{
"order_id": 12345,
"customer": "Olga",
"items": [
{"name": "Haircut", "price": 1500},
{"name": "Manicure", "price": 2000}
],
"total": 3500
}
What's here:
-
Order number 12345
-
Customer — Olga
-
List of services: haircut (1500 rubles) and manicure (2000 rubles)
-
Total: 3500 rubles
What to Know#
-
JSON is used everywhere in APIs
-
You do NOT need to write JSON manually — platforms generate it automatically
-
But reading and understanding JSON is useful for debugging