Building an AI-First Mobile App: React Native + OpenAI + Real-Time Features

What We Built

A field-service mobile app for a utility company with 4,000 field engineers. Engineers inspect infrastructure, log issues, and escalate problems — previously using paper forms and WhatsApp photos. We rebuilt this as an AI-first mobile experience.

The Stack

• ▸Framework: React Native 0.74 (New Architecture enabled)
• ▸AI: OpenAI GPT-4o for vision + text, Whisper for voice transcription
• ▸Backend: FastAPI on AWS with WebSocket support for streaming
• ▸Offline: WatermelonDB for offline-first sync
• ▸State: Zustand + React Query

Key AI Features

1. Visual Defect Detection

Engineers photograph equipment → GPT-4o Vision analyzes the image, identifies defect type, severity, and recommended action within 2 seconds.

const analyzeDefect = async (imageUri: string): Promise<DefectAnalysis> => {
  const base64 = await FileSystem.readAsStringAsync(imageUri, {
    encoding: FileSystem.EncodingType.Base64,
  })

  const response = await openai.chat.completions.create({
    model: 'gpt-4o',
    messages: [{
      role: 'user',
      content: [
        { type: 'image_url', image_url: { url: `data:image/jpeg;base64,${base64}` }},
        { type: 'text', text: 'Analyze this utility infrastructure image. Return JSON with: defect_type, severity (1-5), description, recommended_action, safety_risk (boolean)' }
      ]
    }],
    response_format: { type: 'json_object' }
  })

  return JSON.parse(response.choices[0].message.content!)
}

2. Voice-to-Report

Engineer speaks their inspection notes → Whisper transcribes → GPT-4o structures into standardized report format with all required fields populated.

3. AI-Assisted Escalation

When an issue is flagged, the app drafts an escalation message to the supervisor with full context, attaches relevant photos, and pre-fills the work order form.

Offline-First Architecture

Field engineers work in areas with no connectivity. The app queues all AI requests when offline and processes them as a batch when connectivity resumes, using optimistic UI to keep engineers productive.

Performance

Results for the Client

• ▸Report completion time: 22 min → 7 min
• ▸Data quality score: 61% → 94% (structured fields fully populated)
• ▸Escalation response time: 4.2 hrs → 38 min
• ▸Paperwork eliminated: 100%