Is Protobuf efficient for smaller keys

You’re absolutely right to think that if keys are small and values are long, Protobuf’s advantage becomes less obvious — but it still helps in most cases.

Let’s break it down 🔍:

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Scenario

Imagine this JSON:

{
  "a": "[email protected]",
  "b": "Some very long description about the user which goes on and on and on...",
  "c": "1234567890"
}

Here:

• Keys (a, b, c) are tiny (just 1 character each)
• Values are huge (like the long description)

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Will Protobuf Help Here?

✅ YES… But Not as Much as Before

👉 Protobuf mainly saves space on:

• Keys (Field numbers instead of names)
• Booleans and Numbers (using Varint)
• Optional Fields (Protobuf skips null fields, unlike JSON)

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How Will This Be Stored in Protobuf?

Protobuf Definition:

 User {
  string a = 1;
  string b = 2;
  string c = 3;
}

Protobuf Encoded Data:

0A 11 6A 6F 68 6E 40 65 78 61 6D 70 6C 65 2E 63 6F 6D
12 3F 53 6F 6D 65 20 76 65 72 79 20 6C 6F 6E 67 20 64 ...
1A 0A 31 32 33 34 35 36 37 38 39 30

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Size Comparison

Format	Size	Why?
JSON	132 bytes	Full keys + values + quotes
Protobuf	109 bytes	Only values + small headers
Savings	🔥 17% smaller	But not 50% like earlier!

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But Here’s the Secret 🤯

The real savings come when:

1. You send thousands of messages 🚀
2. Your data contains repeated fields like lists/arrays
3. You’re sending null or optional fields
4. You use integers or booleans

Example:

{
  "id": 123,
  "name": "John Doe",
  "isAdmin": false
}

✅ JSON: 50 bytes
✅ Protobuf: 7 bytes

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What Protobuf Always Saves (No Matter What):

Data Type	JSON Size	Protobuf Size	Savings
Small Numbers	"123" (5 bytes)	7B (1 byte)	80% smaller 🔥🔥
Booleans	"true" (4 bytes)	01 (1 byte)	75% smaller
Null Fields	"email": null (13 bytes)	(Skipped)	100% smaller
Lists	[1,2,3,4,5] (15 bytes)	05 01 02 03 04 05 (6 bytes)	60% smaller

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When JSON Wins (Very Rare 🧐)

✅ Only if:

• You have tiny keys like "a"
• All data is huge strings
• No numbers, booleans, or lists
• No optional fields