Advanced connection information

Connection URI

The driver supports connection to URIs of the form

<SCHEME>://<HOST>[:<PORT>[?policy=<POLICY-NAME>]]
  • <SCHEME> is one among neo4j, neo4j+s, neo4j+ssc, bolt, bolt+s, bolt+ssc.

  • <HOST> is the host name where the Neo4j server is located.

  • <PORT> is optional, and denotes the port the Bolt protocol is available at.

  • <POLICY-NAME> is an optional server policy name. Server policies need to be set up prior to usage.

Notice that the driver does not support connection to a nested path, such as example.com/neo4j/. The server must be reachable from the domain root.

Connection protocols and security

Communication between the driver and the server is mediated by Bolt. The scheme of the server URI determines whether the connection is encrypted and, if so, what type of certificates are accepted.

URL scheme Encryption Comment

neo4j

Default for local setups

neo4j+s

(only CA-signed certificates)

Default for Aura

neo4j+ssc

(CA- and self-signed certificates)

The driver receives a routing table from the server upon successful connection, regardless of whether the instance is a proper cluster environment or a single-machine environment. The driver’s routing behavior works in tandem with Neo4j’s clustering by directing read/write transactions to appropriate cluster members. If you want to target a specific machine, use a BoltDriver object and bolt, bolt+s, or bolt+ssc URI schemes instead.

The connection scheme to use is not your choice, but is rather determined by the server requirements. You must know the right server scheme upfront, as no metadata is exposed prior to connection. If you are unsure, ask the database administrator.

Authentication methods

Basic authentication (default)

The basic authentication scheme relies on traditional username and password. These can either be the credentials for your local installation, or the ones provided with an Aura instance.

from neo4j import GraphDatabase

driver = GraphDatabase.driver(URI, auth=(USERNAME, PASSWORD))

The basic authentication scheme can also be used to authenticate against an LDAP server (Enterprise Edition only).

Kerberos authentication

The Kerberos authentication scheme requires a base64-encoded ticket. It can only be used if the server has the Kerberos Add-on installed.

from neo4j import GraphDatabase, kerberos_auth

driver = GraphDatabase.driver(URI, auth=kerberos_auth(ticket))

Bearer authentication

The bearer authentication scheme requires a base64-encoded token provided by an Identity Provider through Neo4j’s Single Sign-On feature.

from neo4j import GraphDatabase, bearer_auth

driver = GraphDatabase.driver(URI, auth=bearer_auth(token))
The bearer authentication scheme requires configuring Single Sign-On on the server. Once configured, clients can discover Neo4j’s configuration through the Discovery API.

Custom authentication

Use the function custom_auth to log into a server having a custom authentication scheme.

No authentication

If authentication is disabled on the server, the authentication parameter can be omitted entirely.

Custom address resolver

When creating a Driver object, you can specify a resolver function to resolve any addresses the driver receives ahead of DNS resolution. Your resolver function is called with an Address object and should return an iterable of Address objects (or values that can be used to construct Address objects)

Connection to example.com on port 9999 is resolved to localhost on port 7687
import neo4j


def custom_resolver(socket_address):
    # assert isinstance(socket_address, neo4j.Address)
    if socket_address != ("example.com", 9999):
        raise OSError(f"Unexpected socket address {socket_address!r}")

    # You can return any neo4j.Address object
    yield neo4j.Address(("localhost", 7687))  # IPv4
    yield neo4j.Address(("::1", 7687, 0, 0))  # IPv6
    yield neo4j.Address.parse("localhost:7687")
    yield neo4j.Address.parse("[::1]:7687")

    # or any tuple that can be passed to neo4j.Address().
    # This will initially be interpreted as IPv4, but DNS resolution
    # will turn it into IPv6 if appropriate.
    yield "::1", 7687
    # This will be interpreted as IPv6 directly, but DNS resolution will
    # still happen.
    yield "::1", 7687, 0, 0
    yield "127.0.0.1", 7687


driver = neo4j.GraphDatabase.driver("neo4j://example.com:9999",
                                    auth=(USERNAME, PASSWORD),
                                    resolver=custom_resolver)

Further connection parameters

You can find all Driver configuration parameters in the API documentation.

Glossary

LTS

A Long Term Support release is one guaranteed to be supported for a number of years. Neo4j 4.4 is LTS, and Neo4j 5 will also have an LTS version.

Aura

Aura is Neo4j’s fully managed cloud service. It comes with both free and paid plans.

Cypher

Cypher is Neo4j’s graph query language that lets you retrieve data from the database. It is like SQL, but for graphs.

APOC

Awesome Procedures On Cypher (APOC) is a library of (many) functions that can not be easily expressed in Cypher itself.

Bolt

Bolt is the protocol used for interaction between Neo4j instances and drivers. It listens on port 7687 by default.

ACID

Atomicity, Consistency, Isolation, Durability (ACID) are properties guaranteeing that database transactions are processed reliably. An ACID-compliant DBMS ensures that the data in the database remains accurate and consistent despite failures.

eventual consistency

A database is eventually consistent if it provides the guarantee that all cluster members will, at some point in time, store the latest version of the data.

causal consistency

A database is causally consistent if read and write queries are seen by every member of the cluster in the same order. This is stronger than eventual consistency.

NULL

The null marker is not a type but a placeholder for absence of value. For more information, see Cypher Manual — Working with null.

transaction

A transaction is a unit of work that is either committed in its entirety or rolled back on failure. An example is a bank transfer: it involves multiple steps, but they must all succeed or be reverted, to avoid money being subtracted from one account but not added to the other.

backpressure

Backpressure is a force opposing the flow of data. It ensures that the client is not being overwhelmed by data faster than it can handle.

transaction function

A transaction function is a callback executed by an execute_read or execute_write call. The driver automatically re-executes the callback in case of server failure.

Driver

A Driver object holds the details required to establish connections with a Neo4j database.