What is a Stage in Snowflake?

A stage in Snowflake is a temporary or permanent storage location for data files before they are loaded into Snowflake tables or after they are unloaded. Think of it as a data landing zone or buffer area.

Stages can store various file types such as:

• CSV
• JSON
• Parquet
• Avro or ORC

Types of Stages in Snowflake

Snowflake provides three main types of stages:

Stage Type	Category	Description	Example
User Stage	Internal	Automatically created for each user. Accessible only by that user.	@~
Table Stage	Internal	Automatically created for each table. Used to load/unload data specific to that table.	@%my_table
Named Stage	Internal / External	Explicitly created by users. Can point to internal Snowflake storage or external cloud storage.	@my_stage

Internal vs External Stages

Stages can also be categorized as internal (managed by Snowflake) or external (pointing to cloud storage like AWS S3, Azure Blob, or Google Cloud Storage).

Stage Type	Storage Location	Example
Internal Stage	Data stored in Snowflake’s cloud-managed storage. Encrypted and managed automatically.	CREATE STAGE my_internal_stage;
External Stage	Metadata and credentials in Snowflake; actual files remain in your cloud storage.	CREATE STAGE my_ext_stage URL='s3://my-bucket/data/';

How to Create a Stage in Snowflake

Below are example SQL commands to create different types of stages. (Replace paths, credentials, and object names with your own.)

-- Create an internal named stage
CREATE STAGE my_internal_stage
FILE_FORMAT = (TYPE = 'CSV' FIELD_DELIMITER = ',' SKIP_HEADER = 1);

-- Create an external stage (S3 example)
CREATE STAGE my_s3_stage
URL = 's3://my-bucket/data/'
STORAGE_INTEGRATION = my_s3_integration;

-- Example with credentials inline (use cautiously)
CREATE STAGE my_ext_stage_with_creds
URL = 's3://my-bucket/logs/'
CREDENTIALS = (AWS_KEY_ID='XXX' AWS_SECRET_KEY='YYY');

These commands are adapted from Snowflake’s documentation on stages. For further details, see the official Snowflake CREATE STAGE documentation.

Why Do We Need a Stage?

1. Files Need a Landing Zone

Tables store structured data, while raw files like CSV, JSON, or Parquet are unstructured. Stages act as the buffer layer for processing.

2. Separation of Storage and Ingestion

Upload data once into a stage and reuse it across multiple loads or pipelines, saving bandwidth and avoiding repetition.

3. Security and Access Control

Stages allow you to manage access without exposing credentials directly to users.

4. Performance and Reliability

Snowflake parallelizes data loads from stages, tracks load history, and handles retries gracefully.

5. External Data Integration

External stages let Snowflake read from existing object stores without copying data.

6. Data Quality and Auditing

You can LIST, VALIDATE, or PREVIEW files in stages before loading to ensure pipeline integrity.

Is a Stage a Table?

Feature	Stage	Table
Stores	Raw data files (CSV, JSON, Parquet)	Structured rows & columns
Purpose	Temporary landing zone	Permanent queryable store
Query Support	No (must load into table first)	Yes (SQL queries allowed)

Quick Recap

• Stage = buffer zone for raw files before loading to tables.
• Internal stages store files inside Snowflake-managed storage.
• External stages reference cloud object stores.
• You can CREATE stages, LIST files, COPY INTO tables from stages.
• Stages enhance ETL performance, manageability, and security.