Deploy Phoenix App on Seenode | Phoenix Hosting & Deployment Guide

This guide explains how to deploy your existing Phoenix application on seenode.

Prerequisites

Before you begin, ensure you have:

• A seenode account at cloud.seenode.com
• Git configured on your machine
• Existing Phoenix project ready to deploy

Configure for seenode Deployment

Production Configuration

Your service must listen on the same port that you configure in the Port field for the web service. Choose a port (for example, 80 or 8080) and use it both in your Phoenix config and in the dashboard.

For a framework-agnostic explanation of how ports work on seenode, see Configuring Your Application’s Port.

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import Config
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config :hello,
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  generators: [timestamp_type: :utc_datetime]
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# Configures the endpoint
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config :hello, HelloWeb.Endpoint,
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  url: [host: System.get_env("PHX_HOST") || "localhost", port: 80],
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  adapter: Bandit.PhoenixAdapter,
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  render_errors: [
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    formats: [html: HelloWeb.ErrorHTML, json: HelloWeb.ErrorJSON],
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    layout: false
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  ],
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  pubsub_server: Hello.PubSub,
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  live_view: [signing_salt: "Kute9Cn2"],
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  http: [port: 80],
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  server: true

Build Script

Create a build.sh script to streamline deployments:

#!/usr/bin/env bash
# exit on error
set -o errexit

# Initial setup
mix local.hex --force
mix local.rebar --force

# Install dependencies
mix deps.get --only prod

# Compile and build assets
MIX_ENV=prod mix compile
MIX_ENV=prod mix assets.build
MIX_ENV=prod mix assets.deploy

Make the script executable: chmod +x build.sh

Deploy on seenode

::::tip[Troubleshooting] If your deployment fails, the first place to check is the Logs tab in your seenode service dashboard. Build and runtime logs often contain valuable information for diagnosing issues.

Port configuration mismatch

• On seenode, there is no default container port. Ensure your application listens on the port you configured in the Port field.
• Adjust in framework config if needed (for example, in config/prod.exs, update http: [port: 80] to match the Port field value).
• Seeing a 502 Bad Gateway? Your app may not be listening on the expected port.

Common Issues:

OTP Version Problem (Linux-specific)

• Error: Your system’s Erlang/OTP was too old and missing functions Phoenix needed (:public_key.cacerts_get/0).
• Fix: Install a newer OTP (via asdf or manual build) so Phoenix and esbuild can work.

Wrong Build Process

• Error: You were building Phoenix but not doing it in a way that works for seenode’s deploy (wrong script, missing prod build steps).
• Fix: Adjusted build command to properly compile dependencies, assets, and release for production.

Missing SECRET_KEY_BASE

• Error: Phoenix needs a secret key for signing and encryption. It wasn’t set in the deployment environment.
• Fix: Generate one (mix phx.gen.secret) and set it as an environment variable in seenode before starting the app. ::::

Starting from Scratch?

If you don’t have a Phoenix project yet:

Option 1: Use our Template (Recommended)

Option 2: Create from Phoenix Docs + seenode Setup

Follow the official Phoenix documentation to create a new project, then return here for seenode-specific deployment steps.

seenode-Specific Setup Steps:

1. Install Phoenix: mix archive.install hex phx_new
2. Create project: mix phx.new your_project
3. Configure production settings
4. Create build script

Next Steps

Now that your Phoenix app is deployed, here are some recommended next steps: