Scaling Alert Plus: An Enterprise Grade Azure Architecture

Enterprise‑Scale Alerting for Microsoft 365

An enterprise‑grade alerting architecture designed to replace and exceed legacy SharePoint Alerts at scale.

Bamboo Solutions

December 2025

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Architecture Highlights

Why Polling

Built for SharePoint realities. While event driven architectures are ideal in theory, SharePoint Online webhooks currently lack reliable item‑driven architectures are ideal in theory, SharePoint Online webhooks currently lack reliable item‑level detail and introduce operational overhead at scale. Alert Plus uses an optimized polling model to deliver predictable performance, simpler operations, and enterprise reliability.

How We Scale

Horizontal by design. Alert Plus scales using Azure Functions, SharePoint batch requests, delta queries, and identity isolation. This approach enables safe parallel processing of tens of thousands of alerts while respecting SharePoint Online throttling limits.

No Data Loss Guarantee

Reliability over immediacy. In extreme throttling scenarios, alerts may be delayed to the next execution cycle, but changes are never missed. This design prioritizes correctness, trust, and long-term stability.

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Scaling Alert Plus: An Enterprise Grade Azure Architecture 

Executive Summary 

With the retirement of native SharePoint Alerts and the growing demand for enterprise scale notification solutions, Bamboo Solutions designed Alert Plus to operate reliably at a scale exceeding 100,000 active alerts across large Microsoft 365 tenants. This white paper outlines the architectural decisions, tradeoffs, and Azure based scalability strategies that enable Alert Plus to deliver high volume, resilient, and performant alerting without data loss—while respecting SharePoint Online throttling constraints. 

Rather than pursuing theoretical scalability, our approach is grounded in real world SharePoint limits, measured load testing, and operational simplicity. The result is a pragmatic, enterprise ready backend that balances performance, reliability, and maintainability. 

The Core Challenge: Scalable SharePoint Change Detection 

At its core, an alerting platform must reliably detect changes in SharePoint lists and libraries and notify users—often within strict timing expectations. At enterprise scale, this introduces several nontrivial challenges: 

• SharePoint Online throttling limits 
• High alert volumes across many lists and sites 
• Variable alert schedules (ASAP, daily, weekly, custom) 
• High volume email delivery constraints 
• Avoiding data loss under throttling or transient failures 

Alert Plus was designed to meet these challenges while remaining fully compatible with Microsoft 365 governance and security models. 

Event Driven Architecture: Initial Evaluation 

From a purely architectural standpoint, an event driven model is the ideal solution for alerting systems. Our initial design explored SharePoint Webhooks, which notify a registered endpoint whenever a list change occurs. 

Why Webhooks Looked Promising 

• Near Realtime notifications 
• Reduced polling overhead 
• Alignment with modern cloud architecture patterns 

Practical Limitations Encountered 

During implementation and testing, several issues emerged: 

1. Insufficient Change Detail  Webhook notifications provide only high level signals that a change occurred—not the specific items that were added, modified, or deleted. This forced additional queries back to SharePoint to identify the actual changes, reintroducing load and latency. 
2. Operational Overhead  Maintaining webhooks at scale requires: 
3. Tracking which alerts monitor which lists 
4. Updating webhook registrations when alerts are added, modified, or removed 
5. Renewing webhook subscriptions to prevent expiration 
6. Complex Failure Modes  Webhook expiration, missed renewals, or endpoint issues introduce failure scenarios that are difficult to detect and recover from a scale. 

Given these limitations, the webhook approach did not deliver the operational reliability required for enterprise customers. We therefore shifted to a more predictable and controllable model. 

Polling Architecture: A Controlled and Scalable Foundation 

Alert Plus uses a polling based architecture, enhanced with modern SharePoint APIs to maximize efficiency while minimizing throttling risk. 

Baseline Polling Model 

In a polling approach: 

• Lists and libraries are queried on a defined schedule 
• Changes are processed and evaluated against alert criteria 
• Notifications are generated and delivered 

While straightforward, naïve polling can quickly run into throttling limits at scale. 

Key Optimizations for Enterprise Scale 

To make polling viable at high volumes, Alert Plus incorporates several critical optimizations. 

1. Batch Requests 

Alert Plus uses SharePoint batch requests, where multiple API calls are grouped into a single request. 

• SharePoint treats a batch as one request, reducing throttling risk 
• Maximum supported batch size: 20 requests per batch 
• Enables efficient processing of multiple alerts against the same list 

2. Delta Queries 

We leverage delta queries to retrieve only items that have changed since the previous execution. 

Benefits: 

• Significantly reduced payload sizes 
• Faster processing 
• Lower API consumption 

Tradeoffs: 

• Filters are not supported in delta queries 
• Alert specific conditions must be applied as postprocessing filters 

This tradeoff is intentional: postprocessing in Azure is far more scalable than additional SharePoint queries. 

Scheduling Complexity and Alert Timing 

Enterprise alerting introduces a unique challenge: alerts do not all run at the same time. 

• Some alerts run ASAP (15-minute intervals) 
• Others run daily, weekly, or on custom schedules 

An optimization under consideration is querying a list once and triggering all relevant alerts. However, this introduces complexity: 

• Delta queries may need to run using the oldest last run timestamp across alerts 
• This can reduce the effectiveness of delta queries by increasing result sets 

Today, Alert Plus prioritizes correctness and reliability over aggressive consolidation, ensuring alerts run accurately on their defined schedules. 

Azure Functions: The Backbone of Horizontal Scale 

Alert Plus is built on Azure Functions, enabling true horizontal scalability. 

Why Azure Functions 

• Stateless, independently scalable execution 
• Native Azure integration and monitoring 
• Cost efficient scaling based on workload 

Parallel Processing Model 

• Each Azure Function processes a batch of alerts 
• Within a function: 
• Batch requests retrieve SharePoint data 
• Parallel threads evaluate alert logic 

Managing SharePoint Limits 

• Each function processes up to 20 alerts (aligned with batch limits) 
• Multiple functions run concurrently 
• Each function uses a distinct Azure AD app registration (identity) 

This identity isolation allows Alert Plus to: 

• Increase parallelism safely 
• Reduce throttling impact per identity 
• Scale to tens of thousands of alerts across tenants 

Email Delivery at Scale 

At enterprise volumes, email delivery becomes a first-class scalability concern. Alert Plus supports multiple outbound email strategies to align with customer security, compliance, and operational preferences. 

Option A: SendGrid (Bamboo-Managed High-Throughput Delivery) 

Alert Plus can use SendGrid for outbound notifications: 

• High-throughput delivery designed for parallel sends 
• Consistent performance under bursty workloads 
• Clear capacity planning via plan-based limits 

SendGrid is an excellent fit when customers want a predictable scale with minimal dependency on internal mail infrastructure. 

Option B: Customer-Managed SMTP (Enterprise-Controlled Delivery) 

Alert Plus can also deliver alerts through a customer’s SMTP server (for example, an Exchange relay, an internal mail gateway, or a third-party SMTP service managed by the customer). 

This can be an attractive enterprise direction because it: 

• Keeps mail routing, retention, and compliance controls within the customer’s environment 
• Aligns with internal governance (DLP, journaling, archiving, approved outbound gateways) 
• Allows customers to apply their own capacity and policy controls 

Will it scale like SendGrid? 

It can scale well—but the answer depends on how the customer’s SMTP environment is designed: 

• Well-architected SMTP relay/gateway (dedicated relay, load-balanced gateways, proper queueing, rate limits configured for bulk service traffic): can scale to very high throughput. 
• Single mailbox / single connector / default limits (typical line-of-business SMTP usage): will throttle quickly under large alert volumes. 

In other words, SMTP is absolutely viable at enterprise scale when it is treated as a service endpoint (relay/gateway) rather than a single sender identity. 

Practical guidance we apply: 

• Prefer SMTP relay/gateway configurations over mailbox-based sending 
• Support controlled rate limiting and queueing to avoid sudden bursts overwhelming the mail system 
• Ensure customers can provide multiple outbound identities/connectors if needed for throughput and resiliency 

Flexible Deployment Models 

Alert Plus Azure services can run in one of two enterprise-ready deployment models: 

1) Bamboo Shared Azure Environment (Bamboo-Managed) 

• Fastest time to value 
• Bamboo manages infrastructure scaling, monitoring, and operational tuning 
• Ideal for customers who want a fully managed SaaS-style experience 

2) Customer Azure Environment (Customer-Managed Installation) 

• Deployed into the customer’s Azure subscription and network boundary 
• Ideal for customers requiring strict data residency, custom networking, private endpoints, or enhanced governance 
• Enables customers to align identity, monitoring, and outbound email controls with internal standards 

Both models leverage the same core scaling design principles described in this paper; the difference is who owns the operational boundary. 

Throttling and Failure Handling Philosophy 

Traditional Retry Challenges 

In earlier architectures, throttling was handled using exponential retries. At scale—especially with batch and delta queries—this quickly becomes complex and error prone. 

Alert Plus Approach 

• If an alert execution is throttled: 
• It fails gracefully for the current cycle 
• It is prioritized to run first in the next cycle 

Key Outcomes: 

• No data loss 
• Predictable system behavior 
• Slight delivery delay instead of cascading failures 

This design favors system stability over aggressive retry logic. 

Design Philosophy: Pragmatic Enterprise Engineering 

Alert Plus intentionally favors: 

• Simplicity over theoretical perfection 
• Predictable scaling over fragile optimizations 
• Operational transparency over hidden complexity 

As the platform matures and load testing continues, we will: 

• Further optimize batching strategies 
• Reevaluate event driven models as SharePoint APIs evolve 
• Introduce additional intelligent scheduling optimizations 

Our architecture is designed to evolve—without compromising existing customer workloads. 

What This Means for You 

For enterprise customers, architecture decisions are not academic—they directly impact reliability, scalability, and trust. Alert Plus is designed with those realities in mind. 

For IT Leaders and Architects 

• Proven scalability: The platform is engineered to support 100,000+ active alerts using horizontal scaling patterns native to Azure. 
• Predictable performance: Throttling is managed intentionally, ensuring system stability even under heavy load. 
• No data loss: Alerts may be delayed under extreme conditions, but changes are never missed. 
• Cloud-native and future-ready: Built on Azure Functions with a design that can evolve as Microsoft enhances SharePoint APIs. 

For Security and Compliance Teams 

• Identity isolation: Azure AD app registrations are segmented to reduce blast radius and improve control. 
• Microsoft 365 aligned: Fully compatible with SharePoint Online governance and tenant security policies. 
• Auditable and observable: Azure-native logging and monitoring support enterprise operational requirements. 

For Business Users 

• Reliable notifications at scale—even in large, complex tenants 
• Flexible scheduling without sacrificing backend performance 
• Enterprise-grade delivery through a dedicated email infrastructure 

In short, Alert Plus delivers the scale enterprises need without introducing fragile complexity. 

Frequently Asked Questions (FAQ) 

How many alerts can Alert Plus support? 

Alert Plus is architected to scale beyond 100,000 active alerts per tenant through horizontal scaling in Azure. Capacity grows by adding Azure Functions and identities, not by stressing out a single service. 

Why doesn’t Alert Plus use real-time webhooks? 

While event-driven architectures are ideal in theory, SharePoint webhooks currently do not return sufficient item-level detail and introduce significant operational overhead at scale. Our polling-based approach delivers greater reliability and transparency for enterprise workloads. 

Will alerts be delayed if throttling occurs? 

In rare throttling scenarios, alerts may be delayed to the next execution cycle. However, no data is lost, and affected alerts are prioritized in the subsequent run. 

How does Alert Plus prevent SharePoint throttling? 

We mitigate throttling through: 

• Batch requests (up to 20 per batch) 
• Delta queries to limit returned data 
• Distributed Azure Function execution 
• Identity isolation using multiple app registrations 

How are large volumes of emails handled? 

Alert Plus uses SendGrid for email delivery, allowing high-throughput, parallel email sending without relying on a single mailbox or SMTP endpoint. 

Can this architecture evolve in the future? 

Yes. Alert Plus is intentionally designed to evolve. As SharePoint APIs mature, we may reintroduce event-driven models or additional optimizations without disrupting existing customers. 

Conclusion 

Alert Plus is not a lightweight replacement for legacy SharePoint Alerts—it is a purpose built, enterprise grade alerting platform. 

By combining: 

• Azure Functions for horizontal scale 
• Batch requests and delta queries for SharePoint efficiency 
• Identity isolation for throttling control 
• SendGrid for high volume notifications 

Bamboo Solutions delivers a backend architecture capable of supporting 100,000+ alerts with reliability, security, and confidence. 

This is the foundation enterprises expect—and the scale their business demands.