Serverless code that runs when something happens — triggers and bindings, hosting plans, a real example, how to create, run and deploy your first function, and when not to use it.
✍️ Azure Trainings trainers⏱ 4 min read📅 Updated 11 October 2026
Azure Functions is Microsoft’s serverless compute service. You write a small function, choose what starts it — an HTTP request, a timer, a new file or a queue message — and Azure runs it for you. No servers to manage, it scales automatically, and on consumption-based plans you pay mainly for what you use.
TriggerRuns when…HTTPA URL is calledTimerA schedule (CRON expression) is reachedBlob StorageA file is added or changedQueue / Service BusA message arrivesEvent Hubs / Event GridStreaming or system events happenCosmos DBDocuments change
⚡ Short answer
Each function has exactly one trigger. Bindings connect it to other services for input or output — e.g. write the result straight to a queue or Cosmos DB without connection code.
Use cases
Common use cases
🔌
Serverless APIs
Lightweight REST endpoints and webhooks.
🧹
Data processing
Clean or transform files as soon as they land in storage.
⏰
Scheduled jobs
Nightly clean-ups, reports or backups.
📡
Event processing
React to Event Hubs, Service Bus or IoT messages.
🤖
Automation
Notifications, record updates, system integration.
🔄
Data pipelines
Custom logic called from Data Factory or Logic Apps.
Real example
Example: automatic image thumbnails
1
Upload
A product photo lands in the uploads container.
2
Blob trigger
The upload starts the function.
3
Resize
The function creates a thumbnail.
4
Output binding
The thumbnail is saved to the thumbnails container.
No server runs between uploads, and the function scales automatically in busy periods.
🧭 Want to build and deploy your first serverless app? Our trainers guide you in live labs.
VS Code with the Azure Functions extension (or Visual Studio).
Step 2
New project
Pick a language and an HTTP trigger template.
Step 3
Run locally
Test in your browser; use Azurite for storage.
Step 4
Deploy & monitor
Create a function app, deploy and check Application Insights.
For automated releases, deploy with Azure Pipelines or GitHub Actions — see Azure CI/CD pipeline.
Hosting
Hosting plans and function keys
↔️ Swipe the table sideways
PlanBest forFlex ConsumptionEvent-driven scaling with pay-per-useConsumptionSmall, occasional workloadsPremiumPre-warmed instances, VNet support, no cold startsDedicated (App Service plan)Steady workloads on existing App Service capacityAzure Container AppsFunctions as containers alongside microservices
🔑 Function keys
Function key — one functionHost key — all functionsMaster key — admin, never share
🛡️ Good practice
• Keep keys secret and rotate them
• For user-facing APIs prefer Entra ID or API Management
You can learn What is Azure Functions in our live classroom batches near JNTU/KPHB or in live online batches with Azure Trainings. Book a free demo class to see how we teach before you join.
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