Google Cloud Pub/Sub

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What Google Cloud Pub/Sub is

Google Cloud Pub/Sub is an asynchronous messaging service for passing messages between services that produce them and services that process them. It is intended for service-to-service use, including streaming analytics, data integration pipelines, middleware, and parallel task queues, rather than direct communication with end-user or IoT clients. Communication typically has latency on the order of 100 milliseconds. Synchronous cross-zone replication and per-message receipt tracking provide at-least-once delivery. The service has no shards or partitions and provisions automatically after quota is set. Message controls include seeking and replaying messages, dead letter topics, and attribute-based filtering. Integrations include Google Cloud services such as Dataflow, BigQuery, Cloud Storage, Cloud Functions, Cloud Run, and Eventarc, plus third-party services including Splunk, Datadog, Apache Kafka, and ServiceNow. Pub/Sub provides REST and gRPC APIs and client libraries for several languages; API keys are not supported for authentication. The maximum message size is 10 MB. The first 10 GB per month is free; beyond that, pay-as-you-go throughput is listed at $40 a month, with storage at $0.27 per GiB-month.

Who it suits

It suits teams building service-to-service messaging for analytics, data integration, middleware, or parallel task queues. It is not intended for direct communication with end-user or IoT clients.

What it does well

First 10 GB per month is free.
Supports REST and gRPC.
Includes seek, replay, and dead letter topics.
Automatic provisioning after quota is set.
Maximum message size is 10 MB.

What to know first

API keys are not supported for authentication.
Intended for services, not direct end-user or IoT clients.
Typical communication latency is around 100 milliseconds.

Limits

The free monthly tier covers the first 10 GB of data per month. The listed pay-as-you-go plan is $40 a month beyond that amount; throughput beyond 10 GB is listed at $40 per TB, and storage at $0.27 per GiB-month.

Plans

Plan	Billed and limits	Price
Free usage allowance	10 GiB throughput	Free
Pay-as-you-go throughput	After the first 10 GiB per calendar month · Standard message delivery throughput	$40 a month
Free monthly tier	monthly · First 10 GB of data per month	Free
Pay-as-you-go	usage-based monthly · Beyond 10 GB: $40 per TB · storage $0.27 per GiB-month	$40 a month

As cloud.google.com lists them, read 20 Sept 2026. The maker's own page has the final word.

Getting started

Visit https://cloud.google.com/pubsub.
Choose web or API access.
Set a quota for automatic provisioning.
Use REST, gRPC, a client library, or the Google Cloud CLI to authenticate; API keys are not supported.
Start with the free monthly tier or use the listed pay-as-you-go plan.

Verdict

Pub/Sub provides message delivery controls and integrations for service-to-service workloads. Its authentication options, typical latency, and intended audience are important constraints to weigh.

Questions

Is Google Cloud Pub/Sub free?

Yes. The listed free monthly tier covers the first 10 GB of data per month.

How much does the pay-as-you-go plan cost?

The listed plan is $40 a month. Throughput beyond 10 GB is listed at $40 per TB, and storage at $0.27 per GiB-month.

Which platforms and protocols does Pub/Sub support?

The listed platforms are API and web. Supported protocols are REST and gRPC.

Does Pub/Sub support API key authentication?

No. It supports authentication through client libraries, the Google Cloud CLI, and REST.

What services and products does Pub/Sub integrate with?

Google Cloud integrations include Dataflow, BigQuery, Cloud Storage, Cloud Functions, Cloud Run, and Eventarc. Listed third-party integrations include Splunk, Datadog, Apache Kafka, and ServiceNow.

Who makes Google Cloud Pub/Sub?

Pub/Sub is a Google Cloud service. Google Cloud was founded in 1998 and is headquartered in Mountain View, California, United States.

Facts from Google Cloud Pub/Sub's own pages

APIs and libraries: Pub/Sub uses standard gRPC and REST APIs and provides client libraries for several languages, with the product page stating seven languages. · docs.cloud.google.com, 1 Oct 2026
Authentication: Pub/Sub supports client libraries, the Google Cloud CLI, and REST, and does not support API keys as an authentication method. · docs.cloud.google.com, 1 Oct 2026
Automatic scaling: Pub/Sub has no shards or partitions and uses automatic provisioning after you set your quota. · cloud.google.com, 1 Oct 2026
Delivery reliability: Synchronous cross-zone message replication and per-message receipt tracking provide at-least-once delivery at any scale. · cloud.google.com, 1 Oct 2026
Exactly-once processing: Dataflow supports reliable exactly-once processing of Pub/Sub streams. · cloud.google.com, 1 Oct 2026
Founded: 1998 · cloud.google.com, 28 Sept 2026
Headquarters: Mountain View, California, United States · cloud.google.com, 28 Sept 2026
Integrations: Google Cloud integrations include Dataflow, BigQuery, Cloud Storage, Cloud Functions, Cloud Run, App Engine, Cloud Logging, Cloud Monitoring, Workflows, and Eventarc. · cloud.google.com, 1 Oct 2026
Intended users: Pub/Sub is intended for service-to-service communication rather than direct communication with end-user or IoT clients. · docs.cloud.google.com, 1 Oct 2026
Latency: Pub/Sub communication typically has latencies on the order of 100 milliseconds. · docs.cloud.google.com, 1 Oct 2026
Message controls: Pub/Sub supports seek and replay, dead letter topics, and attribute-based message filtering. · cloud.google.com, 1 Oct 2026
Messaging service: Pub/Sub is an asynchronous and scalable messaging service that decouples services producing messages from services processing them. · docs.cloud.google.com, 1 Oct 2026
Security: Pub/Sub offers fine-grained access controls, end-to-end encryption, and HIPAA compliance. · cloud.google.com, 1 Oct 2026
Support resources: Google Cloud provides Pub/Sub documentation, community forums, support, release notes, and system status resources. · docs.cloud.google.com, 1 Oct 2026
Third-party integrations: Listed third-party integrations include Splunk, Datadog, Informatica, Confluent Cloud, Apache Kafka, Elastic, Databricks, and ServiceNow. · cloud.google.com, 1 Oct 2026
Use cases: Pub/Sub is used for streaming analytics, data integration pipelines, service integration middleware, and parallel task queues. · docs.cloud.google.com, 1 Oct 2026