midnight-tooling:proof-server

Midnight Proof Server

The Midnight proof server generates zero-knowledge proofs for Midnight transactions. It can run locally as a Docker container or be accessed as a remote service on testnet/mainnet. The server exposes an HTTP API (default port 6300) that DApps use to request proof generation at runtime.

Local Development

For local development, use the devnet which manages a proof server alongside a node and indexer. Run /midnight-tooling:devnet start to start the full local network. See the devnet skill for details.

The rest of this skill covers working with proof servers directly — useful when connecting to testnet/mainnet or running a standalone instance.

Looking Up Environment Endpoints

Current proof server addresses for testnet and mainnet are published in the Midnight documentation. To look up the latest endpoints:

Use the Midnight MCP server's documentation search tools to search for the relnotes/overview page in the midnightntwrk/midnight-docs repository:

githubGetFileContent(
  owner: "midnightntwrk",
  repo: "midnight-docs",
  path: "docs/relnotes/overview.mdx",
  fullContent: true
)

This page contains the current network environment details including proof server URLs, node endpoints, and indexer endpoints for all active environments.

Terminology

Term	What It Is	How It Runs
Proof server	A service that generates zero-knowledge proofs for Midnight transactions	Docker container (midnightntwrk/proof-server) listening on port 6300
Docker Desktop	The container runtime required to run the proof server	System application, must be running before starting the proof server

The proof server is not the same as the Compact compiler. The compiler produces ZK circuits from Compact source code; the proof server uses those circuits to generate proofs at runtime. See the compact-cli skill for compiler installation, compilation commands, and output file details.

Prerequisites

Docker Desktop must be installed and running before the proof server can start.

Check	Command	Expected
Docker installed	docker --version	Version string
Docker daemon running	docker info	System info (no connection errors)

If Docker is not installed, download it from https://www.docker.com/products/docker-desktop/.

If Docker is installed but not running, start Docker Desktop and wait for it to be ready before proceeding.

Image Version & Tag Selection

The proof server image is published to Docker Hub as midnightntwrk/proof-server with semver-based tags.

Available Tag Types

Tag Pattern	Example	Type
X.Y.Z	7.0.2	Stable release
X.Y.Z-rc.N	8.0.0-rc.4	Release candidate (prerelease)
X.Y.Z-<suffix>	8.0.0-performance.1	Other prerelease
X.Y.Z-arm64 / X.Y.Z-amd64	7.0.2-arm64	Architecture-specific (ignore — Docker selects automatically)
latest	latest	Points to the most recent push (may be a prerelease)

Listing Available Versions

Fetch available tags from the Docker Hub registry API:

curl -s "https://registry.hub.docker.com/v2/repositories/midnightntwrk/proof-server/tags/?page_size=100&ordering=last_updated" \
  | grep -o '"name": *"[^"]*"' \
  | sed 's/"name": *"//;s/"$//'

Resolving the Latest Stable Version

Filter to tags matching strict semver (X.Y.Z only — no prerelease suffixes, no architecture suffixes), sort numerically, and select the highest:

curl -s "https://registry.hub.docker.com/v2/repositories/midnightntwrk/proof-server/tags/?page_size=100&ordering=last_updated" \
  | grep -o '"name": *"[^"]*"' \
  | sed 's/"name": *"//;s/"$//' \
  | grep -E '^[0-9]+\.[0-9]+\.[0-9]+$' \
  | sort -t. -k1,1n -k2,2n -k3,3n \
  | tail -1

The grep -E '^[0-9]+\.[0-9]+\.[0-9]+$' pattern excludes:

• Prerelease tags (8.0.0-rc.4, 8.0.0-performance.1)
• Architecture-specific tags (7.0.2-arm64, 7.0.2-amd64)
• Non-semver tags (latest)

Version Selection Defaults

Scenario	Tag Used
User specifies --version 8.0.0-rc.4	8.0.0-rc.4 (exact)
User specifies --version latest	latest
No version specified	Latest stable (X.Y.Z without prerelease suffix)
No stable versions found	Fall back to latest with a warning
Docker Hub API unreachable	Fall back to latest with a warning

Running the Proof Server

The proof server is memory-intensive. Ensure Docker has at least 4 GB RAM allocated. See references/docker-setup.md for resource configuration.

Start the proof server in detached mode so it runs in the background (replace <tag> with the resolved version):

docker run -d --name midnight-proof-server -p 6300:6300 midnightntwrk/proof-server:<tag> -- midnight-proof-server -v

For example, with version 7.0.0:

docker run -d --name midnight-proof-server -p 6300:6300 midnightntwrk/proof-server:7.0.0 -- midnight-proof-server -v

Flag / Argument	Purpose
-d	Run in detached (background) mode
--name midnight-proof-server	Assign a predictable container name for management
-p 6300:6300	Map host port 6300 to container port 6300
--	Separates Docker options from the container command
midnight-proof-server	The binary to run inside the container
-v	Enable verbose logging inside the proof server

Verifying the Server

After starting, verify the server is healthy:

# Check container is running
docker ps --filter "name=midnight-proof-server" --format "table {{.Names}}\t{{.Status}}\t{{.Ports}}"

# Health check — returns {"status":"ok","timestamp":"..."}
curl -sf http://localhost:6300/health

# Check server version
curl -sf http://localhost:6300/version

# Readiness check — returns {"status":"ok","jobsProcessing":N,"jobsPending":N,"jobCapacity":N,...}
curl -sf http://localhost:6300/ready

# View recent logs
docker logs --tail 20 midnight-proof-server

The server is ready when /health returns {"status":"ok",...} and /ready returns status "ok" with HTTP 200. If /ready returns HTTP 503 with status "busy", the server is running but its job queue is full.

Stopping the Proof Server

docker stop midnight-proof-server

To remove the stopped container (required before starting a new one with the same name):

docker rm midnight-proof-server

Restarting / Replacing the Proof Server

If a container named midnight-proof-server already exists (running or stopped), remove it before starting a new one:

docker rm -f midnight-proof-server 2>/dev/null
docker run -d --name midnight-proof-server -p 6300:6300 midnightntwrk/proof-server:<tag> -- midnight-proof-server -v

Common Issues

Symptom	Cause	Fix
docker: command not found	Docker not installed	Install Docker Desktop
Cannot connect to the Docker daemon	Docker Desktop not running	Start Docker Desktop, wait for it to be ready
port is already allocated on 6300	Another process using port 6300	Stop the conflicting process or use a different port mapping (e.g., -p 6301:6300)
Conflict. The container name "/midnight-proof-server" is already in use	Stopped container with same name exists	Run docker rm midnight-proof-server then retry
Container starts but exits immediately	Image issue or resource constraints	Check logs with docker logs midnight-proof-server
curl: (7) Failed to connect to localhost port 6300	Server not ready or not running	Wait a few seconds for startup; check docker ps for container status

API Endpoints

The proof server exposes the following HTTP endpoints on port 6300:

Endpoint	Method	Purpose	Response
/	GET	Health check (alias for /health)	{"status":"ok","timestamp":"..."}
/health	GET	Health check	{"status":"ok","timestamp":"..."}
/version	GET	Server version	Plain text, e.g. 8.0.0-rc.4
/ready	GET	Readiness and worker pool utilization	{"status":"ok","jobsProcessing":N,"jobsPending":N,"jobCapacity":N,"timestamp":"..."}
/proof-versions	GET	Supported proof versions	Plain text, e.g. ["V2"]

The /ready endpoint returns HTTP 200 when ready and HTTP 503 when the job queue is full (status "busy").

Reference Files

Reference	Content	When to Read
references/docker-setup.md	Standalone Docker proof server setup; cross-references the devnet skill's Docker guide for installation and troubleshooting	Running a proof server outside the devnet (e.g., testnet/mainnet)

For local development Docker setup (node, indexer, and proof server together), see the devnet skill and its references/docker-setup.md.