How Vibra Code works: architecture overview

Vibra Code connects three distinct environments — your phone, a Next.js backend, and E2B cloud sandboxes — through a real-time pipeline. This page explains how those pieces fit together and what happens at each stage when you describe an app.

System diagram

  Phone                     Server                        Cloud
┌──────────┐   API    ┌──────────────┐   Queue    ┌──────────────┐
│  Expo    │ ──────── │   Next.js    │ ────────── │  E2B Sandbox │
│  iOS App │          │   + Convex   │   Inngest  │  + AI Agent  │
└────┬─────┘          └──────┬───────┘            └──────┬───────┘
     │                       │                           │
     └───── real-time sync ──┴─── code generation ───────┘

The phone never talks to the sandbox directly. All communication flows through the backend and Convex, which decouples the mobile client from the long-running build process and lets the phone reconnect at any time without losing progress.

Data flow

User describes an app

The user types or speaks a description in VibraCreateAppScreen. The mobile app calls the backend API (POST /api/create-session) with the prompt, chosen template, and any attached images or audio.

Session created in Convex

The backend creates a sessions record in Convex with status IN_PROGRESS. The mobile app subscribes to this session via Convex’s real-time client — any future status change streams to the phone immediately.

Inngest queues sandbox creation

The backend triggers an Inngest event that queues the create-session function. Inngest handles retries, timeouts, and fan-out, so the Next.js request returns immediately without waiting for the sandbox to be ready.

E2B sandbox starts and clones the template

The create-session Inngest function spawns an E2B sandbox from the pre-built template image. Inside the sandbox, the Expo template repository is cloned, npm dependencies are installed, the Expo dev server is started, and a public tunnel URL is created. The session status in Convex advances through each phase:IN_PROGRESS → CLONING_REPO → INSTALLING_DEPENDENCIES → STARTING_DEV_SERVER → CREATING_TUNNEL → RUNNING

AI agent generates code

Once the sandbox is ready, Inngest runs the run-agent function. The AI agent (Claude Code, Cursor, or Gemini — configured by AGENT_TYPE) reads the user’s prompt and system prompt from lib/prompts.ts, then writes, edits, and runs files inside the sandbox. Every tool operation (file read, file edit, bash command) is written to the messages table in Convex as it happens.

Updates stream to the phone in real time

The mobile app’s Convex subscription receives each new messages record the moment it is written. The native chat UI (built with Texture + IGListKit) renders each message type in a different cell: blue for file reads, orange for file edits, green for bash commands, and Liquid Glass cards for todo task lists.

Phone previews the running app via tunnel URL

When the tunnel URL is available in the sessions record, the mobile app loads the live preview. For Expo React Native templates, the preview renders natively. For Next.js and other web templates, a WKWebView is used. The user can send follow-up messages to the same session — the agent resumes in the existing sandbox without re-cloning.

Backend stack

Component	Technology	Purpose
API server	Next.js 15 (App Router)	Handles client requests, webhooks, and server actions
Real-time database	Convex	Stores sessions, messages, and users; streams changes to clients
Background jobs	Inngest	Queues and runs `create-session`, `run-agent`, and `push-to-github`
Cloud sandboxes	E2B	Isolated environments for code generation and execution
AI agent	Claude Agent SDK / Cursor / Gemini CLI	Writes and edits project files inside the sandbox
Auth	Clerk	User identity for both backend and mobile app
Payments	Stripe (web) + RevenueCat (mobile)	Optional subscription billing

Mobile stack

Component	Technology	Purpose
Runtime	React Native / Expo SDK 54	Cross-platform native mobile foundation
Auth	Clerk	Shared with backend; same user identity
Real-time sync	Convex	Symlinked schema from backend; subscribes to sessions and messages
Chat UI	Texture (AsyncDisplayKit) + IGListKit	60 fps off-main-thread rendering
Navigation	React Navigation	Stack + bottom tab navigator (Home, Create, Profile)
In-app purchases	RevenueCat	Optional mobile subscription management

Convex schema overview

The Convex database is shared between the backend and mobile app. The mobile convex/ directory is a symlink to vibracode-backend/convex/.

`users` table

Stores Clerk user profiles alongside billing and credit state.

Field	Type	Description
`clerkId`	string	Primary identifier from Clerk
`subscriptionPlan`	string	`free`, `weekly_plus`, `pro`, `business`, `enterprise`
`billingMode`	`tokens` \| `credits`	Token mode for Cursor agent; credit mode for Claude agent
`creditsUSD`	number	Available credits (Claude agent, 2× multiplier of real cost)
`messagesRemaining`	number	Messages remaining this period (Cursor/token mode)
`agentType`	`claude` \| `cursor` \| `gemini`	Per-user agent override
`pushToken`	string	Expo push token for notifications

`sessions` table

Each build is one session. The session record tracks the full lifecycle from sandbox creation to completion.

Field	Type	Description
`name`	string	App name provided by the user
`templateId`	string	Which template was used (`expo`, `nextjs`, etc.)
`status`	union	Current phase — see session status lifecycle below
`tunnelUrl`	string	Public preview URL from the sandbox tunnel
`totalCostUSD`	number	Accumulated AI API cost for this session
`envs`	record	Environment variables injected into the sandbox
`githubRepository`	string	Populated after a GitHub push (`owner/repo`)

`messages` table

Every agent action and user message is stored as a messages record. The mobile chat UI reads these in real time.

Field	Type	Description
`sessionId`	ID	Reference to the parent session
`role`	`user` \| `assistant`	Who sent this message
`content`	string	Text content of the message
`edits`	object	File path, old string, new string (for edit operations)
`bash`	object	Command, output, and exit code (for bash operations)
`read`	object	File path (for file read operations)
`todos`	array	Task list items with status and priority
`costUSD`	number	API cost for this message
`modelUsed`	string	Model identifier (e.g., `claude-sonnet-4-20250514`)

Session status lifecycle

A session advances through the following statuses as the sandbox is created and the agent runs. All transitions are written to Convex and stream to the mobile app in real time.

IN_PROGRESS
    │
    ▼
CLONING_REPO
    │
    ▼
INSTALLING_DEPENDENCIES
    │
    ▼
STARTING_DEV_SERVER
    │
    ▼
CREATING_TUNNEL
    │
    ▼
RUNNING
    │
    ▼
CUSTOM  ← AI agent is actively working

The CUSTOM status is used when the agent sends a status message of its own (for example, “Building the authentication flow”). Additional statuses (CREATING_GITHUB_REPO, PUSHING_TO_GITHUB, PUSH_COMPLETE) are used during the optional GitHub push flow.

Project structure

vibra-code/
├── vibracode-backend/            # Next.js 15 + Convex + Inngest
│   ├── app/api/                  # API routes (create-session, run-agent, webhooks)
│   ├── convex/                   # Database schema & query/mutation functions
│   ├── lib/inngest/functions/    # Background jobs
│   ├── lib/e2b/                  # Sandbox configuration
│   ├── lib/prompts.ts            # AI system prompts
│   └── e2b-cursor-template/      # E2B Dockerfile for the sandbox image
│
├── vibracode-mobile/             # React Native / Expo
│   └── apps/expo-go/
│       ├── src/screens/          # Vibra Code screens (VibraCreateAppScreen, etc.)
│       ├── src/services/         # VibraSessionService, VibraNotificationService
│       └── ios/Client/Menu/      # Native chat UI (Texture + IGListKit)
│
└── expo-template/                # Sandbox app template (Git submodule)

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Plans & Billing

How Vibra Code works: architecture overview

System diagram

Data flow

Backend stack

Mobile stack

Convex schema overview

`users` table

`sessions` table

`messages` table

Session status lifecycle

Project structure

Build docs developers (and LLMs) love

Get Started

Using Vibra Code

Plans & Billing

​System diagram

​Data flow

​Backend stack

​Mobile stack

​Convex schema overview

​users table

​sessions table

​messages table

​Session status lifecycle

​Project structure

Build docs developers (and LLMs) love

System diagram

Data flow

Backend stack

Mobile stack

Convex schema overview

`users` table

`sessions` table

`messages` table

Session status lifecycle

Project structure