Convex KMP

Kotlin Multiplatform SDK for Convex — type-safe, coroutine-first, modular backend client for every platform Kotlin runs on.

Features

• Multiplatform — Android, iOS, JVM Desktop, and WasmJs from a single codebase
• Type-safe functions — Call Convex queries, mutations, and actions with compile-time safety
• Result monad — ConvexResult<T> with map, flatMap, recover — no exceptions leak to callers
• Args DSL — Build function arguments with a clean Kotlin DSL instead of raw JSON
• Modular architecture — Pick only the modules you need: core, client, storage, realtime
• Koin DI — First-class dependency injection modules for every component
• File storage — Three-step upload flow, download URLs, and deletion out of the box
• Reactive subscriptions — Observe query results as Kotlin Flows with automatic polling
• Dual auth modes — Bearer tokens (end-user JWT) and admin auth (deploy keys)
• Value-class IDs — DocumentId, StorageId, FunctionReference prevent mixups at compile time

Setup

Add the dependencies you need to your build.gradle.kts:

// Version catalog (gradle/libs.versions.toml)
[versions]
convex = "0.1.0"

[libraries]
convex-core = { module = "io.github.androidpoet:convex-core", version.ref = "convex" }
convex-client = { module = "io.github.androidpoet:convex-client", version.ref = "convex" }
convex-storage = { module = "io.github.androidpoet:convex-storage", version.ref = "convex" }
convex-realtime = { module = "io.github.androidpoet:convex-realtime", version.ref = "convex" }

// build.gradle.kts
kotlin {
    sourceSets {
        commonMain.dependencies {
            implementation(libs.convex.client)   // includes convex-core
            implementation(libs.convex.storage)  // optional
            implementation(libs.convex.realtime) // optional
        }
    }
}

Usage

Create a Client

// Direct instantiation
val convex = Convex.create("https://your-app.convex.cloud") {
    logging = true
}

// Or with Koin DI
startKoin {
    modules(
        convexModule(ConvexConfig(DeploymentUrl("https://your-app.convex.cloud"))),
        storageModule,
        realtimeModule,
    )
}
val convex: ConvexClient by inject()

Authentication

// End-user JWT (from Clerk, Auth0, etc.)
convex.setAuth("eyJhbG...")

// Admin access with deploy key
convex.setAdminAuth("prod:deploy-key-abc123")

// Clear auth
convex.clearAuth()

Queries, Mutations & Actions

// Query with args DSL
val messages = convex.query("messages:list", args {
    "channel" to "#general"
    "limit" to 50
})

messages.onSuccess { data ->
    println("Got messages: $data")
}.onFailure { error ->
    println("Error: ${error.message}")
}

// Mutation
val id = convex.mutation("messages:send", args {
    "body" to "Hello from Kotlin!"
    "channel" to "#general"
})

// Action (external API calls)
val result = convex.action("actions:sendEmail", args {
    "to" to "user@example.com"
    "subject" to "Welcome"
})

Typed Results

@Serializable
data class Message(
    val _id: String,
    val body: String,
    val channel: String,
    val _creationTime: Double,
)

val messages: ConvexResult<List<Message>> = convex.queryTyped("messages:list")

Pagination

val page = convex.queryPaginated(
    path = "messages:list",
    args = args { "channel" to "#general" },
    paginationOpts = PaginationOpts(numItems = 25, cursor = null),
)

page.onSuccess { result ->
    println("Page: ${result.page}")
    println("Has more: ${!result.isDone}")
    println("Next cursor: ${result.continueCursor}")
}

File Storage

val storage: StorageClient by inject()

// One-step upload (generates URL + uploads)
val storageId = storage.uploadFile(
    data = imageBytes,
    contentType = "image/png",
)

// Get download URL
val url = storage.getUrl(storageId = StorageId("storage_abc123"))

// Delete
storage.deleteFile(storageId = StorageId("storage_abc123"))

Realtime Subscriptions

val realtime: RealtimeClient by inject()

realtime.subscribe("messages:list", args {
    "channel" to "#general"
}).collect { result ->
    result.onSuccess { messages ->
        // UI updates automatically
    }
}

Architecture

┌─────────────────────────────────────────────────────────┐
│                      Your App                           │
├──────────┬──────────────┬──────────────┬────────────────┤
│ convex-  │   convex-    │   convex-    │    convex-     │
│ realtime │   storage    │   client     │    core        │
│          │              │              │                │
│ Polling  │ Upload Flow  │ ConvexClient │ ConvexResult   │
│ Flow     │ Download URL │ HttpTransport│ Args DSL       │
│ Subscribe│ Delete       │ Auth State   │ Value IDs      │
│          │              │ Koin Module  │ Models         │
├──────────┴──────────────┼──────────────┤ Serialization  │
│                         │   Ktor       │                │
│                         │   OkHttp     │                │
│                         │   Darwin     │                │
│                         │   Js         │                │
└─────────────────────────┴──────────────┴────────────────┘

Modules

Module	Artifact	Description
convex-core	io.github.androidpoet:convex-core	Value types, result monad, args DSL, serialization models
convex-client	io.github.androidpoet:convex-client	HTTP transport, query/mutation/action execution, auth, Koin DI
convex-storage	io.github.androidpoet:convex-storage	File upload (3-step flow), download URLs, deletion
convex-realtime	io.github.androidpoet:convex-realtime	Reactive query subscriptions as Kotlin Flows

Targets

Platform	Target	Ktor Engine
Android	androidTarget()	OkHttp
iOS	iosX64() iosArm64() iosSimulatorArm64()	Darwin
Desktop	jvm()	OkHttp
Web	wasmJs()	Js

Tech Stack

Layer	Library
Language	Kotlin 2.1.10
Networking	Ktor 3.1.1
Serialization	kotlinx.serialization 1.8.0
Coroutines	kotlinx.coroutines 1.10.1
Date/Time	kotlinx-datetime 0.6.2
DI	Koin 4.0.2
Publishing	vanniktech maven-publish 0.30.0

Build

# Compile all targets
./gradlew compileKotlinJvm

# Run tests
./gradlew jvmTest

# Publish to Maven Central (CI only)
./gradlew publishAllPublicationsToMavenCentral --no-configuration-cache

License

MIT License

Copyright (c) 2026 Ranbir Singh

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.