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Platform Limits & Quotas

Quick reference for common Azure App Service platform limits and quota-related behaviors.

Overview

graph TD
    A[Subscription Quota] --> B[App Service Plan]
    B --> C[Web Apps]
    C --> D[Instance Scale]
    C --> E[Storage Quota]
    C --> F[Networking Limits]
    C --> G[Request Limits]

Request Limits

Limit Typical Value Notes Source
Frontend HTTP timeout 230 seconds Enforced by the App Service frontend for synchronous HTTP requests on Windows apps; Linux apps are documented as approximately 240 seconds. Web request times out in App Service
Max request body 128 MB [Requires verification] This guide does not currently have an App Service-specific Microsoft Learn source for a platform-wide 128 MB limit. Request body limits vary by runtime and web server. Request Limits <requestLimits> (IIS) [Stack-specific]
URL length 8192 characters [Requires verification] No App Service-specific Microsoft Learn source was found for a universal 8192-character limit. URL limits vary by stack and front-end/server behavior. Request Limits <requestLimits> (IIS) [Stack-specific]

Scale and Plan Limits

Tier Max Instances (Typical) Deployment Slots (Typical) Always On Source
Free (F1) 1 0 No Azure App Service limits
Basic (B1) 3 0 No Azure App Service limits
Standard (S1) 10 5 Yes Azure App Service limits
Premium (P1V3 and above) 30+ 20 Yes Azure App Service limits

Regional and SKU variation

Effective limits can vary by region, subscription, and SKU generation. Validate current values in Microsoft Learn and in your subscription quotas.

Storage and File System

Area Behavior Notes
/home Persistent Survives restarts and redeployments
/tmp Ephemeral Reclaimed across restarts/reimages
Logs (/home/LogFiles) Persistent and quota-counted Large log volume can consume storage quota

Deployment and Configuration Limits

Limit Value Notes Source
Max app settings 10,000 [Requires verification] This guide does not currently have a Microsoft Learn source that documents a hard App Service limit of 10,000 settings. Environment block and runtime constraints can be stack-specific. Configure an App Service app [Requires verification]
ZIP deploy upload size 2048 MB CLI/Kudu ZIP deploy package limit. Deploy files to Azure App Service
Slot settings scope Per-slot Mark sensitive values as slot settings. Configure an App Service app

Networking and Connections

Limit/Behavior Value / Pattern Notes Source
SNAT ports per instance (common) 128 Outbound-heavy apps can exhaust ports. Troubleshoot intermittent outbound connection errors
Outbound IPs Multiple, can change Use possibleOutboundIpAddresses for allowlists. Azure App Service limits
WebSocket and long-lived connections Tier-dependent Higher tiers support greater concurrency. Azure App Service limits

Diagnostics and Retention

Area Typical Range Notes Source
Filesystem log retention 30–90 days [Requires verification] Retention depends on storage usage and log configuration; no single App Service platform default was verified for this range. Enable diagnostic logging for apps in Azure App Service [Requires verification]
Live log streaming session Time-limited Streams may disconnect on inactivity. Enable diagnostic logging for apps in Azure App Service
Application Insights retention Configurable Affects cost and forensic depth. Manage usage and costs for Application Insights

Limit-Driven Symptoms

  • Intermittent outbound failures under load (possible SNAT pressure)
  • Sudden 5xx spikes with no code change (plan/resource saturation)
  • Failed uploads or deployments due to artifact size
  • Missing files due to writing into ephemeral paths
  • Slow or dropped long-running HTTP requests over frontend timeout

Run It in the Portal

Portal view: Scale up (App Service plan) blade

Scale up (App Service plan) blade for the Linux plan asp-test-20251107 with Hardware view selected next to Feature view. The main table groups pricing plans into Dev/Test, Production, and Legacy, and shows columns for Name, ACU/vCPU, vCPU, Memory (GB), Remote Storage (GB), Scale (instance), SLA, Cost per hour (instance), and Cost per month (instance). Visible rows include Free F1, Basic B1, Basic B2, Basic B3, Premium v3 P0V3, Premium v3 P1V3, Premium v3 P2V3, Premium v3 P3V3, Premium v3 P1mv3, Premium v3 P2mv3, Premium v3 P3mv3, Premium v3 P4mv3, and Premium v3 P5mv3; the Premium v3 P0V3 row is selected. A Select button appears at the bottom of the blade.

The Scale up (App Service plan) blade is where you compare the plan SKUs that drive most of the limits in the Scale and Plan Limits table above. This capture shows the Hardware view table grouped into Dev/Test, Production, and Legacy, with the selected Premium v3 P0V3 row exposing the per-plan fields that matter operationally: vCPU, Memory (GB), Remote Storage (GB), Scale (instance), and SLA. Because the blade is scoped to the App Service plan rather than the individual web app, it is the right place to confirm whether plan tier and per-instance capacity are part of a saturation or quota problem. Use this view to verify the current plan family and worker size before concluding that a symptom is application-only.

See Also

Sources

Language-Specific Details

Language/runtime behavior (for example, worker model, memory profile, and startup semantics) can change how these limits are experienced in practice. See: