> ## Documentation Index
> Fetch the complete documentation index at: https://sequinstream.com/docs/llms.txt
> Use this file to discover all available pages before exploring further.
# Get started with Redis Strings
> `SET` and `DEL` Postgres changes to Redis key/values in minutes. Build a real-time Redis cache from your Postgres data with change data capture (CDC).
In this quickstart, you'll create a real-time data pipeline that streams changes from a Postgres database to a Redis database. You'll:
* Boot Sequin
* Connect to a sample playground database
* Configure Redis to receive database changes
* See your changes flow in real-time
By the end, you'll have hands-on experience setting up Postgres change data capture (CDC) with Sequin and Redis Strings.
This is the quickstart for streaming Postgres to Redis Strings. See the [how-to guide](/how-to/stream-postgres-to-redis-string) for an explanation of how to use the Redis String sink or the [reference](/reference/sinks/redis-string) for details on all configuration options.
This guide is for Redis Strings which use `SET` and `DEL` to maintain a cache. If you want to use Redis Streams, see our [Redis Streams quickstart](/quickstart/redis-stream).
If you don't already have Redis running, start Redis with Docker:
```bash theme={null}
docker run --name redis -p 6379:6379 -d redis:latest
```
Test your Redis connection with:
```bash theme={null}
redis-cli ping
```
You should see "PONG" in response.
The easiest way to get started with Sequin is with our [Docker Compose file](https://github.com/sequinstream/sequin/blob/main/docker/docker-compose.yaml). This file starts a Postgres database, Redis instance, and Sequin server.
1. Download [sequin-docker-compose.zip](https://github.com/sequinstream/sequin/releases/latest/download/sequin-docker-compose.zip).
2. Unzip the file.
3. Navigate to the unzipped directory and start the services:
```bash theme={null}
cd sequin-docker-compose && docker compose up -d
```
```bash theme={null}
curl -L https://github.com/sequinstream/sequin/releases/latest/download/sequin-docker-compose.zip -o sequin-docker-compose.zip \
&& unzip sequin-docker-compose.zip && rm sequin-docker-compose.zip
cd sequin-docker-compose && docker compose up -d
```
```bash theme={null}
git clone git@github.com:sequinstream/sequin.git
cd sequin/docker
docker compose up -d
```
Check that Sequin is running using `docker ps`:
```bash theme={null}
docker ps
```
You should see output like the following:
```
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
bd5c458cabde sequin/sequin:latest "/scripts/start_comm…" 11 seconds ago Up 9 seconds 4000/tcp, 0.0.0.0:7376->7376/tcp sequin-sequin-1
3bacd89765e7 grafana/grafana "/run.sh" 11 seconds ago Up 11 seconds 0.0.0.0:3000->3000/tcp sequin-sequin_grafana-1
3ad41319a66c postgres:16 "docker-entrypoint.s…" 11 seconds ago Up 11 seconds (healthy) 0.0.0.0:7377->5432/tcp sequin-sequin_postgres-1
6139a5fc4e80 redis:7 "docker-entrypoint.s…" 11 seconds ago Up 11 seconds 0.0.0.0:7378->6379/tcp sequin-sequin_redis-1
7e07a5b052de prom/prometheus "/bin/prometheus --c…" 11 seconds ago Up 11 seconds 0.0.0.0:9090->9090/tcp sequin-sequin_prometheus-1
```
Sequin, Postgres, Redis, Prometheus, and Grafana should be up and running (status: `Up`).
The Docker Compose file automatically configures Sequin with an admin user and a playground database.
Let's log in to the Sequin web console:
After starting the Docker Compose services, open the Sequin web console at [http://localhost:7376](http://localhost:7376):
Use the following default credentials to login:
* Email:
```
admin@sequinstream.com
```
* Password:
```
sequinpassword!
```
To get you started quickly, Sequin's Docker Compose file creates a logical database called `sequin_playground` with a sample dataset in the `public.products` table.
Let's take a look:
In the Sequin web console, click **Databases** in the sidebar.
Click on the pre-configured `sequin-playground` database:
The database "Health" should be green.
Let's get a sense of what's in the `products` table. Run the following command:
```bash theme={null}
docker exec -i sequin-sequin_postgres-1 \
psql -U postgres -d sequin_playground -c \
"select id, name, price from products;"
```
This command connects to the running Postgres container and runs a `psql` command.
You should see a list of the rows in the `products` table:
```
id | name | price
----+-----------------------+-------
1 | Avocados (3 pack) | 5.99
2 | Flank Steak (1 lb) | 8.99
3 | Salmon Fillet (12 oz) | 14.99
4 | Baby Spinach (16 oz) | 4.99
5 | Sourdough Bread | 6.99
6 | Blueberries (6 oz) | 3.99
(6 rows)
```
We'll make modifications to this table in a bit.
With the playground database connected, you can create a [sink](/reference/sinks/overview). This sink will maintain a Redis cache that mirrors your Postgres `products` table:
Click "Sinks" in the sidebar navigation, then click "Create Sink".
Select "Redis String" as the sink type and click "Continue".
In the "Source" card, note that the `sequin-playground` database is selected and all schemas and tables are included. Leave these defaults:
Open the **Transform** card, click **+ Create new transform** and use the following Elixir function in a [Transform function](/reference/transforms#function-transform):
```elixir theme={null}
def transform(action, record, changes, metadata) do
record
end
```
Name the transform `record-only` and click **Create function**.
Navigate back to the **Sinks** tab and select the transform function you just created.
If you don't see the transform function you just created, click the refresh button.
In the `Inital backfill` card, select the `public.products` table to initate a backfill when the sink is created.
In the "Redis Configuration" card, enter your Redis connection details.
* Host: If running locally with Docker, use `host.docker.internal`
* Port: The port Redis is listening on (default: 6379)
Leave the rest of the fields with their default values.
At the bottom of the form, click the "Test Connection" button. With the above configuration, it should succeed.
Sequin can connect to your Redis instance.
As configured, Sequin will:
1. Backfill all current rows into Redis as key/value pairs
2. Set up real-time replication so any changes to the `products` table will be reflected in Redis immediately
3. Use primary keys from Postgres to form Redis keys (e.g., `sequin:products:1`, `sequin:products:2`)
Click "Create Sink" to finish setting up your Redis String sink.
On the new sink's overview page, you should see the "Health" status turn green, indicating data is flowing to your Redis cache.
Let's confirm the cache is working:
Click the "Messages" tab. You'll see a list of the recently delivered messages:
Sequin indicates it backfilled the `products` table to your Redis cache.
Connect to your Redis instance using the Redis CLI:
```bash theme={null}
redis-cli
```
Then list the products in your Redis cache:
```bash theme={null}
KEYS sequin:products:*
```
You should see a list of keys corresponding to products from your Postgres table.
Now, let's look at the actual data for one product:
```bash theme={null}
GET sequin:products:1
```
You should see a JSON representation of the product data.
Data from Postgres is now cached in Redis as strings.
Let's make some changes to the `products` table and see them reflected in your Redis cache.
In your terminal, run the following command to insert a new row into the `products` table:
```bash theme={null}
docker exec -i sequin-sequin_postgres-1 \
psql -U postgres -d sequin_playground -c \
"insert into products (name, price) values ('Organic Honey (16 oz)', 12.99);"
```
In Redis CLI, check if the new product was added to the cache:
```bash theme={null}
KEYS sequin:products:*
```
You should see a new key for the product you just added. View its contents:
```bash theme={null}
GET sequin:products:[new-id]
```
Replace `[new-id]` with the ID of the newly inserted product.
Feel free to try other changes:
```bash theme={null}
docker exec -i sequin-sequin_postgres-1 \
psql -U postgres -d sequin_playground -c \
"update products set price = 7.99 where name = 'Avocados (3 pack)';"
```
Then check the updated value in Redis:
```bash theme={null}
# Find the product ID first
redis-cli --raw KEYS "sequin:products:*" | xargs -I {} redis-cli --raw GET {} | grep "Avocados (3 pack)"
# Then get the specific product (replace ID with the one you found)
GET sequin:products:[id]
```
```bash theme={null}
docker exec -i sequin-sequin_postgres-1 \
psql -U postgres -d sequin_playground -c \
"update products set name = 'Organic Avocados (3 pack)' where name = 'Avocados (3 pack)';"
```
Verify the change in Redis:
```bash theme={null}
# Use the same product ID from the previous example
GET sequin:products:[id]
```
```bash theme={null}
docker exec -i sequin-sequin_postgres-1 \
psql -U postgres -d sequin_playground -c \
"delete from products where name = 'Blueberries (6 oz)';"
```
Check that the key was removed from Redis:
```bash theme={null}
# Find the product ID first (if you don't already know it)
redis-cli --raw KEYS "sequin:products:*" | xargs -I {} redis-cli --raw GET {} | grep "Blueberries"
```
This should return an empty list, indicating the key was removed.
Each change to your Postgres database will be automatically reflected in your Redis cache within a few seconds.
Great work!
You've successfully:
* Set up a complete Postgres to Redis cache synchronization pipeline
* Loaded existing data through a backfill
* Made changes to the `products` table
* Verified Redis cache updates automatically with your database changes
## Applications of Redis Strings Sink
Redis Strings are incredibly versatile and can be used for various caching scenarios:
* **Fast lookups**: Redis can serve product details much faster than a database query
* **Multi-region caching**: Use Sequin to sync records from your primary database to Redis in multiple regions
* **Cache invalidation**: Configure your Redis cache with infinite retention and rely on Sequin to SET and DEL keys as records are updated or deleted
## Ready to stream
Now you're ready to connect your own database to Sequin and start streaming changes:
Connect your Postgres database to Sequin.
Set up a Redis sink to sync your database with Redis.
Learn more about the Redis String sink.