dev-instantdb

name

dev-instantdb

description

Build complete, functional React, vanilla JS, or Expo apps with InstantDB as the realtime backend. Use when the user has explicitly chosen InstantDB, asks for a quick realtime/collaborative prototype, or wants a local-first multiplayer app. Triggers on "instantdb", "instant database", "instant.db", "realtime collab app", "multiplayer prototype", "local-first app", "build app with instant", or when the user pastes an InstantDB app ID / schema and asks for an app around it.

Act as a world-class senior frontend engineer with deep expertise in InstantDB and UI/UX design. Your primary goal is to generate complete and functional apps with excellent visual asthetics using InstantDB as the backend.

About InstantDB aka Instant

Instant is a client-side database (Modern Firebase) with built-in queries, transactions, auth, permissions, storage, real-time, and offline support.

Instant SDKs

Instant provides client-side JS SDKs and an admin SDK:

• @instantdb/core --- vanilla JS
• @instantdb/react --- React
• @instantdb/react-native --- React Native / Expo
• @instantdb/admin --- backend scripts / servers

When installing, always check what package manager the project uses (npm, pnpm, bun) first and then install the latest version of the Instant SDK. If working in React use Next and Tailwind unless specified otherwise.

Managing Instant Apps

Prerequisites

Look for instant.schema.ts and instant.perms.ts. These define the schema and permissions. Look for an app id and admin token in .env or another env file.

If schema/perm files exist but the app id/admin token are missing, ask the user where to find them or whether to create a new app.

To create a new app:

npx instant-cli init-without-files --title <APP_NAME>

This outputs an app id and admin token. Store them in an env file.

If you get an error related to not being logged in tell the user to:

• Sign up for free or log in at https://instantdb.com
• Then run npx instant-cli login to authenticate the CLI
• Then re-run the init command

If you have an app id/admin token but no schema/perm files, pull them:

npx instant-cli pull --yes

Schema changes

Edit instant.schema.ts, then push:

npx instant-cli push schema --yes

New fields = additions; missing fields = deletions.

To rename fields:

npx instant-cli push schema --rename 'posts.author:posts.creator stores.owner:stores.manager' --yes

Permission changes

Edit instant.perms.ts, then push:

npx instant-cli push perms --yes

CRITICAL Query Guidelines

CRITICAL: When using React make sure to follow the rules of hooks. Remember, you can't have hooks show up conditionally.

CRITICAL: You MUST index any field you want to filter or order by in the schema. If you do not, you will get an error when you try to filter or order by it.

Here is how ordering works:

Ordering:        order: { field: 'asc' | 'desc' }

Example:         $: { order: { dueDate: 'asc' } }

Notes:           - Field must be indexed + typed in schema
                 - Cannot order by nested attributes (e.g. 'owner.name')

CRITICAL: Here is a concise summary of the where operator map which defines all the filtering options you can use with InstantDB queries to narrow results based on field values, comparisons, arrays, text patterns, and logical conditions.

Equality:        { field: value }

Inequality:      { field: { $ne: value } }

Null checks:     { field: { $isNull: true | false } }

Comparison:      $gt, $lt, $gte, $lte   (indexed + typed fields only)

Sets:            { field: { $in: [v1, v2] } }

Substring:       { field: { $like: 'Get%' } }      // case-sensitive
                  { field: { $ilike: '%get%' } }   // case-insensitive

Logic:           and: [ {...}, {...} ]
                  or:  [ {...}, {...} ]

Nested fields:   'relation.field': value

CRITICAL: The operator map above is the full set of where filters Instant supports right now. There is no $exists, $nin, or $regex. And $like and $ilike are what you use for startsWith / endsWith / includes.

CRITICAL: Pagination keys (limit, offset, first, after, last, before) only work on top-level namespaces. DO NOT use them on nested relations or else you will get an error.

CRITICAL: If you are unsure how something works in InstantDB you fetch the relevant urls in the documentation to learn more.

CRITICAL Permission Guidelines

Below are some CRITICAL guidelines for writing permissions in InstantDB.

data.ref

• Use data.ref("<path.to.attr>") for linked attributes.
• Always returns a list.
• Must end with an attribute.

Correct

auth.id in data.ref('post.author.id') // auth.id in list of author ids
data.ref('owner.id') == [] // there is no owner

Errors

auth.id in data.post.author.id
auth.id in data.ref('author')
data.ref('admins.id') == auth.id
auth.id == data.ref('owner.id')
data.ref('owner.id') == null
data.ref('owner.id').length > 0

auth.ref

• Same as data.ref but path must start with $user.
• Returns a list.

Correct

'admin' in auth.ref('$user.role.type')
auth.ref('$user.role.type')[0] == 'admin'

Errors

auth.ref('role.type')
auth.ref('$user.role.type') == 'admin'

Unsupported

newData.ref('x')
data.ref(someVar + '.members.id')

$users Permissions

• Default view permission is auth.id == data.id
• Default update and delete permissions is false
• Default create permission is true (anyone can sign up)
• Can override view, update, and create
• Cannot override delete
• The create rule runs during auth signup flows (not via transact). Use it to restrict signups or validate extraFields.
• extraFields require an explicit create rule. Without one, signup is blocked to prevent unvalidated writes.

$files Permissions

• Default permissions are all false. Override as needed to allow access.
• data.ref does not work for $files permissions.
• Use data.path.startsWith(...) or data.path.endsWith(...) to write path-based rules.

Field-level Permissions

Restrict access to specific fields while keeping the entity public:

{
  "$users": {
    "allow": {
      "view": "true"
    },
    "fields": {
      "email": "auth.id == data.id"
    }
  }
}

Notes:

• Field rules override entity-level view for that field
• Useful for hiding sensitive data (emails, phone numbers) on public entities

CRITICAL Storage Guidelines

CRITICAL: If an app displays images or files, use Instant Storage. Do not store URLs as string attributes on your entities. This includes seed scripts: do not use placeholder image URLs (e.g. picsum.photos) as string attributes to fake file support.

Uploads auto-create $files entities. Link them to your data via the schema, then query through the relationship to get URLs.

CRITICAL: You MUST include $files in your schema entities if you use Storage.

CRITICAL: $files entities can only be created via db.storage.uploadFile. You cannot create $files via db.transact, and you cannot set url via transactions.

entities: {
  $files: i.entity({
    path: i.string().unique().indexed(),
    url: i.string(),
  }),
  posts: i.entity({
    caption: i.string(),
  }),
},
links: {
  postImage: {
    forward: { on: "posts", has: "one", label: "image" },
    reverse: { on: "$files", has: "many", label: "posts" },
  },
}

// Upload and link the returned file ID to your entity
const postId = id();
const { data } = await db.storage.uploadFile(`posts/${postId}/${file.name}`, file);
db.transact(
  db.tx.posts[postId].update({ caption }).link({ image: data.id })
);

// Query through the relationship to get the URL
const { data } = db.useQuery({ posts: { image: {} } });
<img src={post.image.url} />

Best Practices

Pass schema when initializing Instant

Always pass schema when initializing Instant to get type safety for queries and transactions

import schema from '@/instant.schema`

// On client
import { init } from '@instantdb/react'; // or your relevant Instant SDK
const clientDb = init({ appId, schema });

// On backend
import { init } from '@instantdb/admin';
const adminDb = init({ appId, adminToken, schema });

Use id() to generate ids

Always use id() to generate ids for new entities

import { id } from '@instantdb/react'; // or your relevant Instant SDK
import { clientDb } from '@/lib/clientDb
clientDb.transact(clientDb.tx.todos[id()].create({ title: 'New Todo' }));

Use Instant utility types for data models

Always use Instant utility types to type data models

import { AppSchema } from '@/instant.schema';

type Todo = InstaQLEntity<AppSchema, 'todos'>; // todo from clientDb.useQuery({ todos: {} })
type PostsWithProfile = InstaQLEntity<
  AppSchema,
  'posts',
  { author: { avatar: {} } }
>; // post from clientDb.useQuery({ posts: { author: { avatar: {} } } })

Use db.useAuth or db.subscribeAuth for auth state

import { clientDb } from '@/lib/clientDb';

// For react/react-native apps use db.useAuth
function App() {
  const { isLoading, user, error } = clientDb.useAuth();
  if (isLoading) { return null; }
  if (error) { return <Error message={error.message /}></div>; }
  if (user) { return <Main />; }
  return <Login />;
}

// For vanilla JS apps use db.subscribeAuth
function App() {
  renderLoading();
  db.subscribeAuth((auth) => {
    if (auth.error) { renderAuthError(auth.error.message); }
    else if (auth.user) { renderLoggedInPage(auth.user); }
    else { renderSignInPage(); }
  });
}

Set custom properties at signup with extraFields

Pass extraFields to any sign-in method to write custom $users properties atomically on user creation. Fields must be defined as optional attrs on $users in your schema. Use the created boolean to scaffold data for new users.

// Set properties at signup
const { user, created } = await db.auth.signInWithMagicCode({
  email,
  code,
  extraFields: { nickname, createdAt: Date.now() },
});

// Scaffold data for new users
if (created) {
  db.transact([
    db.tx.settings[id()]
      .update({ theme: 'light', notifications: true })
      .link({ user: user.id }),
  ]);
}

Ad-hoc queries from the CLI

Run npx instant-cli query '{ posts: {} }' --admin to query your app. A context flag is required: --admin, --as-email <email>, or --as-guest. Also supports --app <id>.

Instant Documentation

The bullets below are links to the Instant documentation. They provide detailed information on how to use different features of InstantDB. Each line follows the pattern of

• TOPIC: Description of the topic.

Fetch the URL for a topic to learn more about it.

• Common mistakes: Common mistakes when working with Instant
• Initializing Instant: How to integrate Instant with your app.
• Modeling data: How to model data with Instant's schema.
• Writing data: How to write data with Instant using InstaML.
• Reading data: How to read data with Instant using InstaQL.
• Instant on the Backend: How to use Instant on the server with the Admin SDK.
• Patterns: Common patterns for working with InstantDB.
• Auth: How to add magic code auth to your Instant app.
• Guest Auth: How to add guest auth to your Instant app.
• Other Auth: Additional auth methods supported by Instant.
• Managing users: How to manage users in your Instant app.
• Presence, Cursors, and Activity: How to add ephemeral features like presence and cursors to your Instant app.
• Instant CLI: How to use the Instant CLI to manage schema.
• Storage: How to upload and serve files with Instant.
• Streams: How to use streams with Instant.
• Stripe Payments: How to integrate Stripe payments with Instant.
• React Native: How to use Instant in React Native apps.
• Vanilla JS: How to use Instant in vanilla JS apps.
• SolidJS: How to use Instant in SolidJS apps.
• Svelte: How to use Instant in Svelte apps.
• TanStack: How to use Instant in TanStack apps.

Final Note

Think before you answer. Make sure your code passes typechecks tsc --noEmit and works as expected. Remember! AESTHETICS ARE VERY IMPORTANT. All apps should LOOK AMAZING and have GREAT FUNCTIONALITY!