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Alex Spinov
Alex Spinov

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Dapr Has a Free API — Heres How to Build Microservices Without the Complexity

#microservices #distributed #opensource #tutorial

Dapr (Distributed Application Runtime) gives microservices superpowers — service discovery, pub/sub, state management, and secrets — through simple HTTP/gRPC APIs. No SDKs needed.

Why Dapr?

  • Sidecar pattern: Runs alongside your app, any language
  • Building blocks: State, pub/sub, service invocation, bindings
  • Pluggable: Swap Redis for Postgres without code changes
  • No SDK needed: Just HTTP calls
  • Kubernetes-native: First-class K8s support
  • Local development: Run without K8s

Install 

# CLI
curl -fsSL https://raw.githubusercontent.com/dapr/cli/master/install/install.sh | bash

# Initialize (local Docker)
dapr init
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Run Your App with Dapr 

dapr run --app-id myapp --app-port 3000 -- node app.js
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Dapr starts a sidecar on port 3500 next to your app.

State Management 

# Save state
curl -X POST http://localhost:3500/v1.0/state/statestore \
  -H 'Content-Type: application/json' \
  -d '[{"key": "user:1", "value": {"name": "Alice", "email": "alice@example.com"}}]'

# Get state
curl http://localhost:3500/v1.0/state/statestore/user:1

# Delete state
curl -X DELETE http://localhost:3500/v1.0/state/statestore/user:1
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Swap Redis for PostgreSQL by changing config — zero code changes.

Pub/Sub 

# Publish event
curl -X POST http://localhost:3500/v1.0/publish/pubsub/orders \
  -H 'Content-Type: application/json' \
  -d '{"orderId": "123", "amount": 49.99}'
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// Subscribe in your app
app.post('/orders', (req, res) => {
  console.log('Order received:', req.body.data);
  res.json({ status: 'SUCCESS' });
});
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Service-to-Service Calls 

# Call another service (Dapr handles discovery)
curl http://localhost:3500/v1.0/invoke/payment-service/method/charge \
  -H 'Content-Type: application/json' \
  -d '{"orderId": "123", "amount": 49.99}'
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No service URLs, no load balancers — Dapr finds the service by name.

Secrets 

curl http://localhost:3500/v1.0/secrets/my-secret-store/DB_PASSWORD
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Works with Kubernetes secrets, HashiCorp Vault, AWS Secrets Manager, Azure Key Vault.

Input/Output Bindings 

# Trigger on Kafka message (input binding)
# Your app receives POST /kafka-input with message data

# Send to external system (output binding)
curl -X POST http://localhost:3500/v1.0/bindings/email \
  -d '{"operation": "create", "data": {"to": "user@example.com", "subject": "Hello"}}'
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Real-World Use Case

A team had 8 microservices with custom service discovery, retry logic, and message queue code in each. After adding Dapr, they deleted 3,000 lines of infrastructure code. Each service just calls localhost:3500 — Dapr handles routing, retries, and message delivery.

Need to automate data collection? Check out my Apify actors for ready-made scrapers, or email spinov001@gmail.com for custom solutions.

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