# Google Cloud Pub/Sub

> Managed messaging with push and pull delivery on Google Cloud

Google Cloud Pub/Sub is an asynchronous, scalable messaging service that decouples producers from consumers, offering push and pull subscriptions, configurable exactly-once delivery, and roughly 100-millisecond latency.

Website: https://cloud.google.com/pubsub

## Use it when

- You are on Google Cloud and want messaging with zero capacity management; throughput is a bill, not a setting.
- Consumers are serverless or intermittent; push subscriptions POST to webhooks, so nothing needs to run continuously.
- The stream should land in BigQuery, Bigtable, or Cloud Storage without consumer code; direct subscriptions write there natively.
- You need per-message parallelism at scale more than partition semantics, with exactly-once delivery configurable where it matters.

## Think twice when

- Strict per-key ordering is central to the design; Pub/Sub is a messaging service, not a partitioned log, and its ordering contract differs from Kafka's.
- Long, repeated replay of history is routine; retention tops out at 31 days and seek-based replay is not the primary access pattern.
- Portability matters; it is Google's API, evaluated and used almost entirely inside Google Cloud.

## How it runs

Fully managed and serverless over gRPC and REST, with automatic scaling and a global namespace (storage stays regional across three zones). Pull and push subscriptions, dead-letter topics, retry policies, and per-topic Single Message Transforms with JavaScript UDFs. Billing is per TiB of throughput plus storage and egress.

## Details

### General

| Attribute | Value |
| --- | --- |
| License | Commercial |
| Deployment | Managed, Serverless |
| Workload | Streaming |
| Operational complexity | Low |
| Pricing | Free, Subscription |
| Documentation | https://docs.cloud.google.com/pubsub/docs/overview |

### Event Streaming

| Attribute | Value |
| --- | --- |
| Protocol | Own API over gRPC and REST |
| Consumption model | Acknowledged messaging, pull or push; replay by seek |
| Storage | Managed; retention up to 31 days |
| What you run | Nothing: no capacity to provision at all |
| Scaling | Automatic; throughput is a bill, not a setting |
| Multi-region | Global namespace, but storage stays in one region across three zones |
| Delivery guarantee | At-least-once; Exactly-once configurable |
| Connectors | Import topics from Kafka, Kinesis and GCS; direct subscriptions to BigQuery and Bigtable |
| Transformations | Single Message Transforms, including JavaScript UDFs, per topic or subscription |
| Billing unit | Message throughput by the TiB, plus storage and egress |

## Capabilities

- [Event Streaming](https://matca.io/capabilities/event-streaming)

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Source: https://matca.io/google-cloud-pubsub
Last updated: 2026-08-31T11:40:49.405Z