Source: https://daphnislabs.com/services/nodejs-development

# Node.js Development

Node.js APIs, integration services and realtime backends, with clear boundaries for asynchronous work and failure recovery.

[Discuss your project](https://daphnislabs.com/contact?service=nodejs-development) [Try the example](https://daphnislabs.com/services/nodejs-development#worked-example)

**Event loop**

Receive Dispatch Respond

**Background workers** evt-104 evt-105 evt-104 Repeated event, one effect

## Tools & technologies

-   Node.js
-   TypeScript
-   SQL database
-   Job queue

## Process a repeated payment webhook

Capability Example

A provider sends the same successful payment event twice.

### Verify

### Deduplicate

### Publish

Illustrative data. Nothing is sent to an external system.

Example workspace 1 / 3

### Verified webhook

```
event_id: evt-104
Signature checked
Event type: payment succeeded
```

Check the webhook signature and expected event shape.

### Duplicate event

```
evt-104 already recorded
Payment state unchanged
Repeated receipt acknowledged
```

Record the provider event ID before applying the state change.

### Persisted notification

```
Downstream event stored
Worker publishes status
Processing trace retained
```

Notify downstream services from a persisted event record.

One payment-state transition and a traceable delivery record for follow-up processing.

Follow the record through the next step

## APIs and event-driven work that can recover.

### Product APIs

Connect browser and mobile clients to validated application operations.

### Integration services

Receive webhooks, reconcile external records and manage retries.

### Realtime features

Deliver live updates without making socket connections the source of truth.

## Services with useful failure behavior.

-   **Typed Node.js service**
-   **API and event contracts**

-   **Load and retry tests**
-   **Deployment and monitoring configuration**

## Keep blocking work away from the request loop.

### Concurrency

Measure long tasks and move unsuitable CPU-heavy work outside the request loop.

### Provider behavior

Retries, event ordering and rate limits differ across external APIs.

## Questions before we start.

### Can Node.js work with our database?

Usually. Driver support, transaction behavior and connection limits are checked against the actual database and deployment environment.

### Can you support an existing JavaScript backend?

Yes. Improvements can be staged around tests, service boundaries and selected TypeScript adoption.

[Full Stack Development](https://daphnislabs.com/services/full-stack-development) [React & Next.js Development](https://daphnislabs.com/services/react-development) [MEAN Stack Development](https://daphnislabs.com/services/mean-stack-development) [Multiplayer Backend Development](https://daphnislabs.com/services/multiplayer-backend)

## Bring your starting point.

Share API consumers, expected traffic and examples of external events the service must handle.

[Discuss your project](https://daphnislabs.com/contact?service=nodejs-development) [Explore related services](https://daphnislabs.com/services/full-stack-development)