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Sandboxes expose an internal metadata API at http://169.254.169.254 that lets code inside the VM scale memory up or down on the fly. CPU scales proportionally to memory. This is useful for workloads with variable resource needs — scale up before a heavy compilation or ML inference, then scale back down to save resources.
The elasticity endpoint is only accessible from inside the sandbox. It is not exposed through the control plane API or SDKs.

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Scale Memory

Send a POST to /v1/scale with the desired memory in MB: 
curl -s -X POST http://169.254.169.254/v1/scale \
  -H "Content-Type: application/json" \
  -d '{"memoryMB": 4096}'
CPU is adjusted proportionally — you only need to specify memory. The permissible sizes are:
MemoryvCPU
1GB1 (best-effort)
4GB1
8GB2
16GB4
32GB8
64GB16

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Check Current Limits

curl -s http://169.254.169.254/v1/limits

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Example: Rust Compilation

Rust builds are memory-hungry. You can alias cargo to scale up before compilation and scale back down after: 
alias cargo='_cargo_scaled'
_cargo_scaled() {
  # Scale up to 16GB / 4 vCPU before build
  curl -sf -X POST http://169.254.169.254/v1/scale \
    -H "Content-Type: application/json" -d '{"memoryMB": 16384}'

  # Run the actual cargo command
  command cargo "$@"
  local exit_code=$?

  # Scale back down to 4GB / 1 vCPU
  curl -sf -X POST http://169.254.169.254/v1/scale \
    -H "Content-Type: application/json" -d '{"memoryMB": 4096}'

  return $exit_code
}
Add this to your sandbox’s ~/.bashrc or inject it via sandbox.exec.run so every cargo build, cargo test, etc. automatically gets the extra resources.

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Example: Auto-Scaling Script

A simple shell script that monitors memory pressure and scales automatically: 
#!/bin/sh
SCALE_API="http://169.254.169.254/v1/scale"
MIN_MB=1024
MAX_MB=8192
SCALE_UP_THRESHOLD=80
SCALE_DOWN_THRESHOLD=30
COOLDOWN=30
last_scale=0

while true; do
  mem_total=$(awk '/MemTotal/{print $2}' /proc/meminfo)
  mem_avail=$(awk '/MemAvailable/{print $2}' /proc/meminfo)
  usage_pct=$(( (mem_total - mem_avail) * 100 / mem_total ))
  total_mb=$((mem_total / 1024))
  now=$(date +%s)
  elapsed=$((now - last_scale))

  if [ $usage_pct -gt $SCALE_UP_THRESHOLD ] && [ $elapsed -gt $COOLDOWN ]; then
    new_mb=$((total_mb * 2))
    [ $new_mb -gt $MAX_MB ] && new_mb=$MAX_MB
    if [ $new_mb -gt $total_mb ]; then
      echo "usage=$usage_pct% -> scaling UP to ${new_mb}MB"
      curl -sf -X POST "$SCALE_API" \
        -H "Content-Type: application/json" \
        -d "{\"memoryMB\":$new_mb}"
      last_scale=$now
    fi
  elif [ $usage_pct -lt $SCALE_DOWN_THRESHOLD ] && [ $total_mb -gt $MIN_MB ] && [ $elapsed -gt $COOLDOWN ]; then
    new_mb=$((total_mb / 2))
    [ $new_mb -lt $MIN_MB ] && new_mb=$MIN_MB
    if [ $new_mb -lt $total_mb ]; then
      echo "usage=$usage_pct% -> scaling DOWN to ${new_mb}MB"
      curl -sf -X POST "$SCALE_API" \
        -H "Content-Type: application/json" \
        -d "{\"memoryMB\":$new_mb}"
      last_scale=$now
    fi
  fi

  sleep 5
done