insomnia-plugin-slow-network

slow-network

Insomnia plugin that simulates slow network conditions to test APIs under poor connectivity.

Installation in Insomnia

• Open Insomnia
• Go to Application → Preferences (or Ctrl/Cmd + ,)
• Click the Plugins tab
• Click Install Plugin
• Enter insomnia-plugin-slow-network and confirm
• The plugin will be installed and appear in the list

How to Use in Insomnia

• Create or open a request
• In the Headers tab, add the X-Slow-Network header
• Set the value (see options below) and send the request
• The response will be delivered in chunks with delay, simulating a slow network

Configuration Options

Option 1: Template Tags (recommended)

• Add the header: use {% slowNetworkHeader %} as header name, or type X-Slow-Network
• Set the value to a template tag: {% slowNetwork3g %}, {% slowNetworkEdge %}, etc.
• Send the request

Available presets:

Tag	Returns	Simulates
{% slowNetworkHeader %}	X-Slow-Network	Header name
{% slowNetwork3g %}	256 B, 200 ms	3G
{% slowNetworkEdge %}	128 B, 400 ms	EDGE
{% slowNetwork2g %}	64 B, 700 ms	2G
{% slowNetworkCustom chunk delay %}	custom	Custom

Option 2: Manual value

Set the X-Slow-Network header to a value in the format chunk|delay:

X-Slow-Network: 256|200

• chunk – Size of each chunk in bytes (e.g. 256)
• delay – Delay between chunks in milliseconds (e.g. 200)

Example

GET https://api.example.com/users
Headers:
  X-Slow-Network: 128|400

This simulates an EDGE-like connection: 128 bytes per chunk, 400 ms between chunks.

The Problem

APIs are usually tested on fast, stable connections. In production, many users face:

• Weak mobile signals (3G, EDGE, 2G)
• Congested networks
• Unstable connections

Without testing under these conditions, you may ship APIs that:

• Time out too early or too late
• Provide poor loading feedback
• Fail in ways you didn't anticipate

What This Plugin Solves

This plugin throttles request and response transfers by sending data in small chunks with configurable delays. You can:

• Test how your API behaves on slow networks
• Tune timeouts and retry logic
• Validate loading states and UX before production

How It Works

• Proxy – When a request includes the X-Slow-Network header, the plugin starts a local proxy server.
• Interception – The request is redirected to localhost. The proxy receives it and forwards to the actual target.
• Throttling – Both the request body and response body are sent in chunks of N bytes, with M ms delay between each chunk.
• Cleanup – After the response finishes, the proxy is stopped.

The format is chunk|delay (e.g. 256|200 = 256 bytes per chunk, 200 ms between chunks).