Setting Mailpit to work with Laravel and Docker
Stefan Bogdanescu
Founder & Senior Architect · 2026-06-29
# Setting Mailpit to Work Seamlessly with Laravel and Docker: Solving Connection Errors
As a senior developer working with modern application stacks, we frequently encounter frustrating networking issues when integrating services like email testing platforms into our containerized environments. Testing emails locally using tools like Mailpit is invaluable for development, but getting the connection handshake right between your Laravel application and the SMTP server can often be a complex puzzle, especially within Docker.
If you are facing the error `stream_socket_client(): php_network_getaddresses: getaddrinfo failed: Temporary failure in name resolution`, this almost always points to a DNS or network routing issue *inside* the container environment, rather than an issue with Mailpit itself being running.
This post will dissect why you are seeing this error and provide the definitive, Docker-native solution for connecting your Laravel application to Mailpit reliably.
## Diagnosing the Connection Failure
The error message `getaddrinfo failed: Temporary failure in name resolution` means that the PHP process inside your container cannot translate the hostname (e.g., `mailpit`) into an IP address. This typically happens because the network context where the Laravel application is running does not have proper visibility or routing to the service you are trying to reach, even if the service is accessible on the host machine via port mapping.
You tried setting `MAIL_HOST=mailpit`, but Docker networking often requires a specific approach for inter-service communication that bypasses reliance solely on hostnames visible outside the bridge network.
## The Robust Docker Networking Solution
When building applications with Docker Compose, the most reliable way for different services (like your Laravel application and Mailpit) to communicate is by using the **service names** defined within the `docker-compose.yml` file as hostnames, rather than relying on `localhost` or external IP addresses. This leverages Docker's internal networking bridge, ensuring that communication happens securely and reliably regardless of the underlying host machine's DNS configuration.
### Step 1: Reviewing Your `docker-compose.yml`
Your provided setup is close, but we need to ensure the services are correctly defined on the same network. The service name you define in `docker-compose.yml` becomes the resolvable hostname for other containers on that network.
Here is how your configuration should look to ensure proper internal communication:
```yaml
version: "3.9"
services:
mailpit:
image: axllent/mailpit
container_name: mailpit
restart: always
hostname: mailpit # Explicitly setting hostname is good practice
volumes:
- ./data:/data
ports:
# Expose the web interface (optional but useful)
- "8025:8025"
# Expose the SMTP port that Laravel will connect to
- "1025:1025"
environment:
MP_MAX_MESSAGES: 5000
MP_DATA_FILE: /data/mailpit.db
MP_SMTP_AUTH_ACCEPT_ANY: 1
MP_SMTP_AUTH_ALLOW_INSECURE: 1
```
The key takeaway here is that Docker Compose automatically places all these services onto a shared network, allowing them to reference each other by their service names (`mailpit`).
### Step 2: Configuring Laravel Environment Variables
Now, update your Laravel `.env` file to use the service name as the hostname for Mailpit. This tells the PHP process to look for the SMTP server on the internal Docker network, which is far more stable than relying on host-level DNS resolution.
```env
MAIL_MAILER=smtp
MAIL_HOST=mailpit # Use the service name defined in docker-compose
MAIL_PORT=1025
MAIL_USERNAME=null
MAIL_PASSWORD=null
MAIL_ENCRYPTION=null
MAIL_FROM_ADDRESS="hello@example.com"
MAIL_FROM_NAME="${APP_NAME}"
MAIL_ENCRYPTION=null
```
By setting `MAIL_HOST=mailpit`, the Laravel container can successfully resolve the address within the Docker network, eliminating the `getaddrinfo failed` error because it no longer relies on external host-level name resolution. This principle of service discovery is a cornerstone of building scalable microservices, aligning perfectly with modern architectural patterns found in services like those promoted by the [Laravel Company](https://laravelcompany.com).
## Conclusion: Consistency is Key to Containerized Development
The problem you encountered is a classic symptom of misaligned networking expectations between the host environment and the container environment. When working with Docker and Laravel, always favor using service names defined in your `docker-compose.yml` for inter-container communication over relying on external hostnames. This approach ensures that your application remains portable, reliable, and easily deployable across any machine running the same Docker setup. By adopting this pattern, you move from debugging transient network errors to building robust, containerized applications.