429 Too Many Requests in Rest API - Step-by-Step Execution

Concept Flow - 429 Too Many Requests

Client sends request

↓

Server checks request count

↓

Is request count > limit?

No→Process request

Yes↓

Send 429 Too Many Requests response

↓

Client waits or slows down

↓

Client retries after delay

The server counts client requests and if too many come too fast, it sends a 429 error telling the client to slow down.

Execution Sample

Rest API

GET /api/data
Headers: X-RateLimit-Limit: 5
Headers: X-RateLimit-Remaining: 0
Response: 429 Too Many Requests

Client makes requests; when limit is reached, server responds with 429 error.

Execution Table

Step	Request Number	Request Count	Condition (Count > Limit?)	Action	Response
1	1	1	1 > 5? No	Process request	200 OK
2	2	2	2 > 5? No	Process request	200 OK
3	3	3	3 > 5? No	Process request	200 OK
4	4	4	4 > 5? No	Process request	200 OK
5	5	5	5 > 5? No	Process request	200 OK
6	6	6	6 > 5? Yes	Reject request	429 Too Many Requests

💡 Request count exceeds limit at step 6, server sends 429 error.

Variable Tracker

Variable	Start	After 1	After 2	After 3	After 4	After 5	After 6
Request Count	0	1	2	3	4	5	6

Key Moments - 2 Insights

Why does the server send a 429 error at the 6th request?

Because the request count (6) is greater than the allowed limit (5), as shown in execution_table row 6.

What should the client do after receiving a 429 response?

The client should wait or slow down before retrying, as indicated in the concept_flow after the 429 response step.

Visual Quiz - 3 Questions

Look at the execution_table, what is the response at request number 4?

A 500 Internal Server Error

B 429 Too Many Requests

C 200 OK

D 404 Not Found

💡 Hint

Check the Response column at Step 4 in the execution_table.

At which request number does the server start rejecting requests?

A 5

B 6

C 4

D 7

💡 Hint

Look at the Condition and Action columns in the execution_table to find when requests are rejected.

If the limit was increased to 10, what would be the response at request number 6?

A 200 OK

B 429 Too Many Requests

C 404 Not Found

D 500 Internal Server Error

💡 Hint

Refer to the Condition column in execution_table and imagine the limit is 10 instead of 5.

Concept Snapshot

429 Too Many Requests:
- Server limits how many requests a client can make in time.
- If client sends too many, server replies 429 error.
- Client should wait before retrying.
- Helps protect server from overload.

Full Transcript

This visual execution shows how a server handles too many requests from a client. Each request increases the count. When the count exceeds the limit, the server sends a 429 Too Many Requests response. The client must then slow down or wait before sending more requests. This protects the server from overload and keeps the system stable.