HelixDB Python SDK

The Python SDK pairs an idiomatic query-builder DSL with synchronous and asynchronous clients for sending HelixDB queries to POST /v2/query or executing them against an embedded database. The async client uses HTTPX; the sync API remains unchanged.

from helixdb import Client, Predicate, g, read_batch

query = (
    read_batch()
    .var_as(
        "users",
        g()
        .n_with_label("User")
        .where(Predicate.eq("status", "active"))
        .limit(25)
        .value_map(["$id", "name", "status"]),
    )
    .returning(["users"])
)

request = query.to_query_request()
result = Client("http://localhost:6969").query(request)

Async Client

Reuse one AsyncClient so its HTTPX connection pool can serve many requests. There is no timeout unless you configure one on the client or request.

import asyncio

import httpx

from helixdb import AsyncClient

async def main():
    limits = httpx.Limits(max_connections=20, max_keepalive_connections=10)
    async with AsyncClient(timeout=10.0, limits=limits) as client:
        first, second = await asyncio.gather(
            client.query(request),
            client.execute(request, writer_only=True, timeout=2.0),
        )
        return first, second

results = asyncio.run(main())

AsyncClient, AsyncQueryBuilder, and AsyncQueryExecutionRequest are also exported from the compatibility import path helix_db. Builder methods preserve the synchronous writer, warm, durability, authorization, and response contracts.

HTTP cancellation propagates as asyncio.CancelledError; the response stream is closed and the client remains reusable. For embedded operations, use asyncio.timeout(...) when a cancellation boundary is required. HTTPX AsyncBaseTransport instances can be injected for custom networking or tests; the client owns and closes an injected transport. Calling await client.close() more than once is safe.

Warm a read with client.execute(request, warm_only=True). Helix Cloud fans the ordinary read out to every eligible backend, discards the results, and returns an empty successful response after at least one target succeeds. Pass writer_only=True as well to warm only the authoritative writer. Warm writes return an error before backend execution. A standalone local warm read can return its normal query payload instead.

The DSL emits the same query JSON AST as the Rust, TypeScript, and Go SDKs. Python methods use snake_case; compatibility aliases such as nWithLabel and valueMap are also available for users translating TypeScript examples directly.

Query Parameters

from helixdb import Predicate, define_params, g, param, read_batch

params = define_params({
    "tenant_id": param.string(),
    "limit": param.i64(),
})

query = (
    read_batch()
    .var_as(
        "users",
        g()
        .n_with_label("User")
        .where(Predicate.eq("tenantId", params.tenant_id))
        .limit(params.limit)
        .value_map(["$id", "name", "tenantId"]),
    )
    .returning(["users"])
)

body = query.to_query_json(
    params,
    {"tenant_id": "acme", "limit": 10},
    query_name="find_users",
)

Row Bindings

Use bind(...) when a multi-hop traversal needs to keep earlier elements correlated with later results. project_distinct_bindings(...) emits one row per projected tuple.

from helixdb import BindingProjection, g, read_batch, sub

query = (
    read_batch()
    .var_as(
        "workloads",
        g()
        .n_with_label("Service")
        .bind("service")
        .optional(sub().in_("CREATES").bind("deployment"))
        .union([sub().in_("MANAGES").bind("owner"), sub().out("ROUTES_TO").bind("workload")])
        .project_distinct_bindings([
            BindingProjection.binding("service", "$id", "service_id"),
            BindingProjection.coalesce(
                [
                    BindingProjection.binding_ref("deployment", "$id"),
                    BindingProjection.binding_ref("owner", "$id"),
                    BindingProjection.binding_ref("workload", "$id"),
                ],
                "workload_id",
            ),
        ]),
    )
    .returning(["workloads"])
)

Embedded Client

Install the SDK and matching native runtime:

python -m pip install helix-db helix-db-embedded

from helixdb import Client, InMemory

client = Client.embedded(InMemory("app"))
try:
    response = client.query(request)
finally:
    client.close()

Cache profiles are fixed when the handle opens. Vector-memory-only mode disables SlateDB and object-store caches, not canonical persistence.

from helixdb import EmbeddedCacheConfig, VectorMemoryOnly

client = Client.embedded(
    InMemory("app"),
    cache=EmbeddedCacheConfig(256 * 1024 * 1024, VectorMemoryOnly()),
)

Client.embedded_reader(...) opens an existing disk or object-storage database read-only. Stored routes and query bundles are not supported.

The async client awaits native UniFFI operations directly and supports the same writer, reader, memory, disk, object-storage, and cache configurations.

from helixdb import AsyncClient, Disk, InMemory

async def embedded_query(request):
    writer = await AsyncClient.embedded(InMemory("app"))
    async with writer:
        return await writer.query(request)

async def read_checkpoint(request):
    reader = await AsyncClient.embedded_reader(Disk("./data", "app"))
    async with reader:
        return await reader.query(request)

Concurrent asyncio.gather(...) calls are passed to the native runtime without a synchronous wrapper. Native graph loading remains available only on Client.

Native graph algorithms

from helixdb import Client, SourcePredicate, g
from helixdb.graph import BetweennessOptions, GraphSelection

client = Client()
selection = GraphSelection(
    node_traversal=g().n_where(SourcePredicate.has_key("$id")),
    edge_traversal=g().e_where(SourcePredicate.has_key("$id")),
    direction="directed",
    allow_full_scan=True,
)
graph = client.graph(selection)
scores = graph.betweenness_centrality(BetweennessOptions.graphify_default())

The returned object retains the immutable Rust topology. Every accessor and algorithm runs locally without another Helix read. Native wheels are required for this graph API and embedded mode; server clients do not require the native runtime.

Run the SDK tests from the repository root:

python -m pip install -e './sdks/python[dev]'
python -c 'import doctest, helixdb.async_client as module; raise SystemExit(doctest.testmod(module).failed)'
python -m unittest discover -s sdks/python/tests