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Network Conditions

Network Conditions adds artificial latency to matching requests using named presets modeled after Apple’s Network Link Conditioner. Use it to test loading states, timeout handling, and degraded-network UX without leaving Rockxy. Phase 1 simulates added request-start latency only. Bandwidth shaping, packet loss, and jitter are planned for a future release.

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Entry Points

ActionHow to Access
Network Conditions windowTools > Network Conditions… (Cmd+Opt+N)
Quick-create from requestRight-click a captured request > Tools > Network Conditions…
Quick-create from domainRight-click a domain in the sidebar > Tools > Network Conditions

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Presets

Each preset maps to a fixed latency value applied before the request is forwarded upstream:
PresetLatencyUse Case
3G400 msMobile fallback testing
EDGE850 msExtreme slow-network edge cases
LTE50 msTypical mobile latency
Very Bad Network2000 msTimeout and retry logic
WiFi2 msBaseline with minimal overhead
CustomUser-definedSpecific latency requirements

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One-Active Enforcement

Only one Network Conditions rule can be active at a time. When you enable a rule, all other Network Conditions rules are automatically disabled. This applies across both the dedicated window and the general Rules list. A warning banner appears in the Network Conditions window if multiple rules are somehow enabled simultaneously.

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Window Layout

The Network Conditions window (880 x 480) follows the standard Rockxy tool-window layout:
  1. Inline Toolbar — Disable All button, Search field, Add Rule button
  2. Info Bar — help text describing the feature
  3. Table — columns for Enabled (toggle), Name, Scope (URL pattern), Profile (preset name), Latency (ms), and Status (Active / Inactive / Conflict)
  4. Bottom Bar — Add (+) and Remove (-) buttons, rule count

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Creating a Network Condition

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From the dedicated window

  1. Open Tools > Network Conditions… or press Cmd+Opt+N.
  2. Click Add Rule or the + button.
  3. Enter a rule name and URL pattern (Exact Path, Subpaths, or Regex).
  4. Select a preset or choose Custom and enter a latency value in milliseconds.
  5. Click Add Rule.

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From a captured request (quick-create)

  1. Right-click any request in the traffic list.
  2. Choose Tools > Network Conditions… from the context menu.
  3. The edit sheet opens pre-filled with the request’s host and path.
  4. Select a preset and click Add Rule.

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From the sidebar (domain quick-create)

  1. Right-click any domain in the sidebar.
  2. Choose Tools > Network Conditions from the context menu.
  3. The edit sheet opens pre-filled with the domain as a subpath match.

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How It Works

Network Conditions rules use the networkCondition action type internally, separate from generic throttle rules. When a matching request arrives:
  1. The rule engine evaluates rules in order and finds the first matching enabled rule.
  2. If it is a Network Conditions rule, the proxy holds the request for the configured latency before forwarding it upstream.
  3. The delay applies to the request initiation phase — response streaming is not paced.
HTTPS requests are delayed after TLS interception, so the delay applies to the decrypted HTTP traffic inside the tunnel, not to the CONNECT handshake.

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Persistence

Network Conditions rules are persisted alongside all other rules in ~/Library/Application Support/Rockxy/rules.json. They survive app restarts and can be exported/imported through the standard rule system.

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Limitations

  • Latency only — no bandwidth shaping, packet loss, or jitter simulation in Phase 1
  • Request-start delay — the delay is applied before forwarding; response body streaming is not paced
  • WebSocket frames — latency applies to the initial HTTP upgrade request, not to individual WebSocket frames after the connection is established
  • One active rule — only one Network Conditions rule can be active at a time