Depot Has a Free API — Here's How to Build Docker Images 40x Faster

#depot #docker #cicd #devops

A team lead told me: 'Our Docker builds took 18 minutes in GitHub Actions. Developers lost focus waiting. We switched to Depot — same Dockerfile, 28 seconds.' That's not a typo. 18 minutes → 28 seconds.

What Depot Offers for Free

Depot free tier:

100 build minutes/month
Shared cache — persistent build cache between runs
Native multi-platform — build arm64 + amd64 simultaneously
Drop-in replacement — works with existing Dockerfiles
CI/CD integration — GitHub Actions, GitLab CI, CircleCI
No emulation — native arm64 builders (not QEMU)

Quick Start

# Install CLI
curl -L https://depot.dev/install-cli.sh | sh

# Login
depot login

# Build (drop-in docker build replacement)
depot build -t myapp:latest .

# Multi-platform build
depot build --platform linux/amd64,linux/arm64 -t myapp:latest .

# Push to registry
depot build -t ghcr.io/myorg/myapp:latest --push .

GitHub Actions

name: Build and Push
on: [push]

jobs:
  build:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: depot/setup-action@v1
      - uses: depot/build-push-action@v1
        with:
          context: .
          push: true
          tags: ghcr.io/myorg/myapp:${{ github.sha }}
          platforms: linux/amd64,linux/arm64

Why It's Fast

Traditional Docker build in CI:
1. Start fresh VM (no cache)          → 0:00
2. Pull base image                     → 0:30
3. Install apt packages                → 3:00
4. Install npm dependencies            → 5:00
5. Build application                   → 8:00
6. Build arm64 via QEMU (emulated)     → 18:00
Total: 18 minutes

Depot:
1. Use persistent builder (warmed up)  → 0:00
2. Cache hit: base image layers        → 0:02
3. Cache hit: apt + npm layers         → 0:05
4. Build only changed layers           → 0:20
5. Native arm64 builder (no QEMU)      → 0:28
Total: 28 seconds

REST API

# List projects
curl 'https://depot.dev/api/v1/projects' \
  -H 'Authorization: Bearer YOUR_API_TOKEN'

# List builds
curl 'https://depot.dev/api/v1/projects/PROJECT_ID/builds' \
  -H 'Authorization: Bearer YOUR_API_TOKEN'

# Get build details
curl 'https://depot.dev/api/v1/builds/BUILD_ID' \
  -H 'Authorization: Bearer YOUR_API_TOKEN'

Depot vs GitHub Actions Docker Build

Depot	GitHub Actions
Persistent cache	Cache lost each run
Native arm64	QEMU emulation (10x slower)
Dedicated builders	Shared runners
28s average	18min average
$0 (free tier)	Free but slow