Type-safe, coroutine-first SDK and Worker gateway enabling publishable-key access to D1, KV, R2, and realtime APIs; includes Result monad, D1 table API, KV JSON helpers, and Worker template.
Kotlin Multiplatform SDK and Worker gateway for Cloudflare — a type-safe, coroutine-first client for D1, KV, R2, and realtime-style app backends.
Cloudflare gives you powerful backend primitives, but not a mobile-safe anonKey model like Supabase. Cloudflare KMP adds that missing application layer:
KMP app -> Cloudflare KMP SDK -> your Worker gateway -> D1 / KV / R2 / Durable Objects
Apps receive only a Worker URL and publishable key. Cloudflare account tokens, D1/KV/R2 bindings, and secrets stay server-side in your Worker.
This is an alpha scaffold. The SDK modules compile, the Kotlin/JS Worker dry-runs with Wrangler, and the Worker template implements D1 and KV routes.
Production gaps are explicit: R2 signing and Durable Object realtime are API-shaped but not fully implemented yet.
Add the dependencies you need to your build.gradle.kts.
// Version catalog (gradle/libs.versions.toml)
[versions]
cloudflare-kmp = "0.1.0-alpha01"
[libraries]
cloudflare-core = { module = "io.github.androidpoet:cloudflare-core", version.ref = "cloudflare-kmp" }
cloudflare-client = { module = "io.github.androidpoet:cloudflare-client", version.ref = "cloudflare-kmp" }
cloudflare-d1 = { module = "io.github.androidpoet:cloudflare-d1", version.ref = "cloudflare-kmp" }
cloudflare-kv = { module = , version.ref = }
cloudflare-r2 = { module = , version.ref = }
cloudflare-realtime = { module = , version.ref = }
// build.gradle.kts
kotlin {
sourceSets {
commonMain.dependencies {
implementation(libs.cloudflare.client) // includes cloudflare-core
implementation(libs.cloudflare.d1) // optional
implementation(libs.cloudflare.kv) // optional
implementation(libs.cloudflare.r2) // optional
implementation(libs.cloudflare.realtime) // optional
}
}
}
Until the first Maven Central release is visible, use publishToMavenLocal or a GitHub Packages/maven repository from your fork.
val cloudflare = createCloudflareClient(
workerUrl = "https://api.example.workers.dev",
publishableKey = "cfpub_live_xxx",
)
With user auth:
val cloudflare = createCloudflareClient(
workerUrl = "https://api.example.workers.dev",
publishableKey = "cfpub_live_xxx",
accessTokenProvider = { sessionStore.currentAccessToken },
)
Every request sends:
x-cloudflare-publishable-key: cfpub_live_xxx
Authorization: Bearer optional-user-token
@Serializable
data class Todo(
val id: String,
val title: String,
val done: Boolean,
)
val todos: CloudflareResult<List<Todo>> = cloudflare
.d1()
.from("todos")
.select<Todo> {
eq(, )
order(, descending = )
limit()
}
todos.onSuccess { items ->
println()
}.onFailure { error ->
println()
}
Insert:
cloudflare
.d1()
.from("todos")
.insert(Todo(id = "todo_1", title = "Ship Cloudflare KMP", done = false))
Update:
cloudflare
.d1()
.from("todos")
.update(Todo(id = "todo_1", title = "Ship Cloudflare KMP", done = true)) {
eq("id", "todo_1")
}
Delete:
cloudflare
.d1()
.from("todos")
.delete {
eq("id", "todo_1")
}
val kv = cloudflare.kv()
kv.putText("APP_KV", "settings/theme", "dark")
kv.get("APP_KV", "settings/theme").onSuccess { theme ->
println(theme)
}
Typed JSON:
@Serializable
data class UserProfile(val name: String)
kv.putJson("APP_KV", "users/$userId/profile", UserProfile(name = "Ranbir"))
kv.getJson<UserProfile>("APP_KV", "users/$userId/profile")
cloudflare
.r2()
.createUploadUrl(
bucket = "avatars",
path = "users/$userId/avatar.png",
contentType = "image/png",
)
.onSuccess { signedUrl ->
println("Upload with ${signedUrl.method}: ${signedUrl.url}")
}
The SDK API is present. The MVP Worker returns 501 for R2 routes until Worker-side SigV4 signing is implemented.
val realtime = createRealtimeClient(
workerUrl = "https://api.example.workers.dev",
publishableKey = "cfpub_live_xxx",
)
realtime.connect()
val subscription = realtime.subscribe("room:lobby") { event ->
println("Event: $event")
}
Realtime is currently an API surface. The planned transport is Worker WebSockets backed by Durable Objects.
The Worker template validates the publishable key and talks to Cloudflare bindings:
GET /health
GET /d1/{table}?eq.id=123&limit=1
POST /d1/{table}
PATCH /d1/{table}?eq.id=123
DELETE /d1/{table}?eq.id=123
GET /kv/{namespace}/{key}
POST /kv/{namespace}/{key}
DELETE /kv/{namespace}/{key}
Dry-run the Worker:
./gradlew :worker-template:jsProductionExecutableCompileSync
cd worker-template
wrangler deploy --dry-run --outdir dist
Deploy after replacing the D1/KV IDs in worker-template/wrangler.toml:
cd worker-template
npm install
npm run build
wrangler deploy
./gradlew :cloudflare-core:jvmTest \
:cloudflare-client:compileKotlinJvm \
:cloudflare-d1:compileKotlinJvm \
:cloudflare-kv:compileKotlinJvm \
:cloudflare-r2:compileKotlinJvm \
:cloudflare-realtime:compileKotlinJvm \
:worker-template:jsProductionExecutableCompileSync
Contributions are welcome! If you've found a bug, have an idea for an improvement, or want to contribute new features, please open an issue or submit a pull request.
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MIT License. See LICENSE.
workerUrl + publishableKey, never Cloudflare account API tokens in the appCloudflareResult<T> with map, flatMap, recover, onSuccess, and onFailurefrom("todos").select<Todo>(), insert, update, and delete/realtime endpoint, subscribe/broadcast over a wss:// socket with auto-reconnect and backoffCloudflareApiClient for https://api.cloudflare.com/client/v4 (D1 database + query, KV namespaces/values/bulk, R2 buckets) with the standard {success, errors, messages, result, result_info} envelope, for server-side/admin use| Module | Purpose |
|---|
cloudflare-core | Shared config, headers, CloudflareResult, errors |
cloudflare-client | Ktor HTTP transport and client factory |
cloudflare-d1 | D1 table API |
cloudflare-kv | KV text and JSON helpers |
cloudflare-r2 | R2 signed URL API shape |
cloudflare-realtime | Realtime channel API surface |
worker-template | Kotlin/JS Worker gateway |
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