Full-stack preview in seconds with zero config

Preview environments should feel automatic. If you open a branch, you should get a live URL with your app, services, and realistic data. No tickets. No YAML spelunking. No “who owns staging” pings.

Developers already spend too much time fighting fires and hunting answers. A 2024 Cisco survey reported that developers spend more than 57 percent of their time in war rooms solving performance issues instead of building features.¹ Independent summaries echoed the same finding.² These delays compound when your team waits for shared staging.

Upsun removes that friction with zero-config branch previews that mirror production and spin up in seconds, so you can ship with confidence. Today, we will discover how it works and learn how to put it into use.

What “zero config” means on Upsun

On Upsun, every branch can become a fully independent environment with your code, a copy of your database, search index, and files, plus an auto-generated URL you can share with reviewers. Read the overview: Upsun integrates with GitHub to automatically create an environment when a branch or pull request is opened, rebuild it on push, and remove it on merge. For developers, this means absolute feature isolation without requiring abysitting of infrastructure.

Behind the scenes, Upsun uses a single YAML configuration file in your Git repository that our AI onboarding can pre-generate based on your repository, allowing you to be even more productive.

Why do preview environments per branch matter

• Shorter feedback loops. Pre-production environments tied to pull requests enable teams to review the actual application before merging, which accelerates approvals and reduces rework.³
• Better delivery performance. Teams that minimize handoffs and accelerate feedback tend to improve DORA metrics, such as lead time for changes and change failure rate.⁴ ⁵
• Fewer “works on my machine” bugs. Identical clones of services and configuration make defects reproducible early (see Upsun’s environment model).
   

Clone the production environment safely

Real data makes previews useful, but it must be protected. Upsun previews inherit data from the parent environment, so you get realistic behavior. Use built-in sanitization patterns and hooks to remove personal data when cloning or syncing environments automatically. External regulators and standards bodies recommend anonymisation and data minimization for non-production use, so sanitizing test data is not just a preference, it is good governance.⁶ ⁷

The Upsun approach: zero config, full stack

• Git-driven config. Keep infra next to code in .upsun/config.yaml. Upsun can generate a starting config for you, and you commit changes as code.
• Per-branch environments. Open a branch, and Upsun can stand up an isolated environment with apps, services, routes, variables, storage, and infrastructure. When you push, it builds. When you merge, it cleans up.
• Instant data cloning with sanitization. Clone databases, caches, and files from production, then apply sanitization to keep previews safe.
• Multi-service orchestration. Describe multiple apps and services in one file and deploy them together so frontend, API, and background workers stay in sync.
• Observability and APM. Each environment exposes metrics and activity so you can validate performance before merging.

Example: minimal config to get going

Upsun can generate this automatically, but here is the gist so you see how little you need to manage:

.upsun/config.yaml
applications:
  app:
    type: "nodejs:20"
    build:
      commands:
        - npm ci
        - npm run build
    web:
      commands:
        start: "npm run start"
    relationships:
      - "db:postgresql"
services:
  db:
    type: "postgresql:15"
routes:
  "https://{default}/":
    type: upstream
    upstream: "web:http"

Commit this, open a branch, and Upsun will create a full-stack preview with the app and a Postgres clone. Configure details as code over time; you do not need to wire environments manually.

Implementation checklist

1. Initialize the project: Run the Upsun CLI command upsun init to generate a starter YAML based on your stack.
2. Connect GitHub or GitLab: Enable the integration so every branch and pull request gets its own environment automatically.
3. Sanitize data: Add a sanitization script or use guidance to mask PII during environment clones. External guidance from the ICO and EDPB reinforces best practices for anonymizing test data.⁶ ⁷
4. Share the URL. Every preview has an automatic domain. You can also configure custom domains for previews when needed.
5. Measure what matters. Use previews to shift validation left. Faster, smaller changes improve DORA outcomes over time.⁴ ⁵
6. Pause idle previews. Save resources by pausing environments when a review stalls.

How does this improve speed, quality, and predictability

• Speed. Branch-level previews remove staging wait time and reduce back-and-forth on PRs.³ ⁴
• Quality. Full-stack parity catches integration issues before merge and encourages realistic testing.
• Consistency. One YAML file standardizes services, routes, and deploy behavior across teams.
• Reduced toil. Platform automation means fewer manual environment chores.
• Predictable cost. Ephemeral previews clean up automatically and can be paused when idle.

Upsun’s product pillars emphasize speed, simplicity, scalability, standardization, security, and sustainability. Keep the grind out of shipping and let developers focus on building.

FAQs developers ask

How is this different from a shared staging server?
Shared staging often diverges from production and becomes a bottleneck in resource allocation. Per-branch previews are isolated, short-lived, and mirror the production configuration, which accelerates reviews and reduces the risk of errors.³ ⁴

Do previews work for complex stacks?
Yes. Upsun orchestrates multiple apps and backing services from a single config, so your front end, API, workers, and databases deploy together.

What about data privacy?
Use automatic sanitization when cloning data into previews. Regulators provide guidance on effective anonymisation for non-production use.⁶ ⁷

Next steps

• Get started with Upsun
• Configure GitHub integration
• Learn the YAML structure
• Sanitize preview data guide

Sources

1. Cisco Newsroom: Developers spending more time firefighting issues
2. Developer-Tech: Cisco survey summary
3. Microsoft Azure docs: Pre-production environments for pull requests
4. DORA 2024 Accelerate State of DevOps Report
5. Octopus: Understanding DORA metrics
6. UK ICO guidance on anonymisation
7. European Data Protection Board guidance overview