Dropletshigh

• API surface is DigitalOcean’s proprietary REST/CLI/Terraform tooling rather than OpenStack Nova/Neutron/Glance APIs (Droplets are managed via DigitalOcean UI/CLI/API/Terraform).
• Billing is usage-based with per-second billing (60-second minimum and monthly cap) rather than the typical per-hour, quota-based charge model users often see in OpenStack-based clouds.
• Droplets include a bundled outbound transfer allowance with each plan (starting at 500 GiB/month) rather than a separate bandwidth quota/metering model users often encounter in OpenStack deployments.
• Droplets are described as Linux-based VMs on virtualized hardware with local SSD storage, whereas OpenStack deployments commonly expose distinct block storage (Cinder) and image services (Glance) and may not bundle bandwidth/monitoring/firewalls into the instance offering.

Volumeshigh

• Uses proprietary /v2/volumes API instead of OpenStack Cinder /v3/{project_id}/volumes; actions like attach/detach/resize via undocumented POST /volumes/{id}/actions rather than /os-volume-attach etc.
• Enforces single-instance attachment only (one Droplet at a time); OpenStack supports multi-attach volumes.
• Volume names must be globally unique per region; OpenStack uses IDs primarily with optional display names.
• Size specified in GiB (binary) with 1 GiB to 16 TiB range; OpenStack typically GiB but flexible.

VPC (VPC Network)high

• Region-scoped: a VPC network is created in a specific datacenter region and resources must be in that same region to be attached, whereas OpenStack Neutron networks/subnets are generally available across all AZs in a region and attachments are controlled by network reachability rather than an explicit region slug ().
• Resource migration is limited: Droplets require snapshot/recreate to move between VPCs and some resources (Kubernetes clusters, load balancers, NAT gateways) cannot be migrated between VPCs, whereas in OpenStack you typically can attach/detach ports or move router interfaces without recreating servers (behavior depends on deployment, but Neutron’s object model supports it) ().
• NAT is a managed NAT Gateway with tiered capacity (1–16 increments; each increment gives 25 Mbps symmetrical bandwidth and 100 GiB outbound transfer/month) and can be set as the default gateway for the VPC, whereas OpenStack commonly expresses egress via Neutron routers with SNAT and does not use this specific ‘size tier’ model ().
• Security-policy coupling differs: DigitalOcean notes Cloud Firewall rules affect both public and VPC traffic and rules must specify whether they apply to the public or private IP range, whereas in OpenStack security groups are generally applied to ports and are not framed as “public vs private IP range” rule modes ().