Stacktower

Inspired by XKCD #2347, Stacktower renders dependency graphs as physical towers where blocks rest on what they depend on. Your application sits at the top, supported by libraries below—all the way down to that one critical package maintained by some dude in Nebraska_.

🚀 Try the Web App · 📖 Read the Story

Installation

Homebrew (recommended)

The Homebrew install includes everything out of the box — GitHub authentication, private repo access, and all CLI features work without extra configuration.

brew tap stacktower-io/homebrew-tap
brew install --cask stacktower

Alternative: build from source

⚠️ Important: Building from source (or go install) does not embed the GitHub App credentials needed for stacktower github login, stacktower github install, and stacktower parse github. These commands will fail unless you manually set STACKTOWERGITHUBAPPCLIENTID and STACKTOWERGITHUBAPP_SLUG. All other commands (parse, render, resolve, etc.) work fine without these.

Go install:

go install github.com/stacktower-io/stacktower/cmd/stacktower@latest

Clone & build:

git clone https://github.com/stacktower-io/stacktower.git
cd stacktower
make build

Quick Start

# Render the included Flask example (XKCD-style tower is the default)
stacktower render examples/real/flask.json -o flask.svg
Parse a package from a registry, then render it
stacktower parse python fastapi -o fastapi.json
stacktower render fastapi.json -o fastapi.svg
Or pipe parse straight into render
stacktower parse python flask | stacktower render - -o flask.svg

Want more? The CLI generates static SVGs locally. Stacktower Cloud adds interactive towers, dependency history tracking, automated PR diffs via the GitHub Action, AI-powered health grading, and team dashboards — all from the same parse output.

Global Options

These flags apply to all commands:

| Flag | Description | | ----------------- | ---------------------------------------------------------- | | -v, --verbose | Enable debug logging (search space info, timing details) | | -q, --quiet | Suppress non-essential output (success messages, stats) | | -h, --help | Show help for any command | | --version | Show version information |

stacktower parse

Parse dependency graphs from package registries or local manifest files.

stacktower parse <language> <package-or-file> [flags]
stacktower parse <manifest-file>                       # Auto-detect language from filename
stacktower parse github [owner/repo]                   # Parse from a GitHub repository

Supported languages: python, rust, javascript, ruby, php, java, go

Parse Options

| Flag | Description | | ----------------------- | ------------------------------------------------------------------------------------ | | -o, --output | Output file (if omitted: TTY shows summary/tree, piped stdout emits JSON) | | -n, --name | Project name for manifest parsing (auto-detected if not set) | | --max-depth N | Maximum dependency depth (default: 10, max: 100) | | --max-nodes N | Maximum packages to fetch (default: 5000, max: 50000) | | --workers N | Concurrent fetch workers (default: 20) | | --enrich | Enrich with GitHub metadata — stars, maintainers (default: true) | | --contributors | Fetch GitHub contributors for Nebraska rankings (slower API calls) | | --security-scan | Best-effort scan for known vulnerabilities via OSV.dev | | --dependency-scope | Dependency scope: prod_only (default) or all (includes dev dependencies) | | --include-prerelease | Include prerelease versions (alpha/beta/rc/dev) in resolution | | --runtime-version | Target runtime version for marker evaluation (e.g., 3.11 for Python) | | --no-cache | Disable caching |

From Package Registries

stacktower parse python fastapi -o fastapi.json                  # PyPI
stacktower parse rust serde -o serde.json                        # crates.io
stacktower parse javascript yargs -o yargs.json                  # npm
stacktower parse ruby rails -o rails.json                        # RubyGems
stacktower parse php monolog/monolog -o monolog.json             # Packagist
stacktower parse java com.google.guava:guava -o guava.json       # Maven Central
stacktower parse go github.com/gin-gonic/gin -o gin.json         # Go Module Proxy

Use package@version to pin a specific version. Without it, the latest version is resolved:

stacktower parse python fastapi@0.104.1 -o fastapi.json
stacktower parse rust serde@1.0.195 -o serde.json
stacktower parse javascript @angular/core@17.0.0 -o angular.json  # scoped packages work too

From Manifest Files

stacktower parse python poetry.lock -o deps.json
stacktower parse python requirements.txt -o deps.json
stacktower parse rust Cargo.toml -o deps.json
stacktower parse javascript package.json -o deps.json
stacktower parse ruby Gemfile -o deps.json
stacktower parse php composer.json -o deps.json
stacktower parse java pom.xml -o deps.json
stacktower parse go go.mod -o deps.json

When the argument exists on disk or matches a known manifest filename, Stacktower auto-detects the language from the filename so you can omit the language subcommand:

stacktower parse poetry.lock -o deps.json
stacktower parse package-lock.json -o deps.json
stacktower parse Cargo.lock -o deps.json

The project name (root node) is auto-detected from the manifest or a sibling file:

• Cargo.toml: [package].name
• go.mod: module directive
• package.json: name field
• composer.json: name field
• pom.xml: groupId:artifactId
• poetry.lock / requirements.txt: pyproject.toml (sibling)
• Gemfile: *.gemspec (sibling)

stacktower parse python requirements.txt --name="my-project" -o deps.json

Metadata Enrichment

By default, parse enriches packages with GitHub metadata (stars, maintainers, last commit) for richer visualizations. Set GITHUB_TOKEN for higher rate limits:

export GITHUBTOKEN=yourtoken
stacktower parse python fastapi -o fastapi.json
Skip enrichment if you don't need it
stacktower parse python fastapi --enrich=false -o fastapi.json

Vulnerability Scanning

Add the --security-scan flag to annotate every package with its highest vulnerability severity via OSV.dev:

stacktower parse python fastapi --security-scan -o fastapi.json
stacktower parse javascript package.json --security-scan -o deps.json

When --security-scan is enabled, Stacktower performs a best-effort query to OSV.dev in a single batch request and writes severity data (critical, high, medium, low) into each node's metadata when available. The scanned graph is cached separately from non-scanned graphs, so subsequent runs are instant.

During rendering, vulnerable packages are automatically colour-coded by severity. Use --show-vulns=false to suppress the colours while keeping the data in the graph:

stacktower render fastapi.json --show-vulns=false -o fastapi.svg

Parse from GitHub

Parse dependencies directly from a GitHub repository with interactive selection:

stacktower parse github                              # Full interactive flow
stacktower parse github owner/repo                   # Select ref + manifest
stacktower parse github owner/repo --ref v2.0.0      # Parse at specific tag
stacktower parse github owner/repo --ref main         # Explicit branch
stacktower parse github owner/repo --timeout 10m      # Custom timeout

| Flag | Description | | --------------- | --------------------------------------------------- | | --ref | Git ref (branch, tag, or commit SHA) | | --timeout | Timeout for GitHub operations (default: 5m) | | --public-only | Show only public repositories in interactive picker |

Private repos: Install the GitHub App with stacktower github install and grant access to the repos you need.

Piping

When parse detects that stdout is piped, it emits clean JSON with no chrome — making it composable with other tools:

# Pipe directly into render
stacktower parse python flask | stacktower render - -o flask.svg
Pipe into jq for analysis
stacktower parse python requests | jq '.nodes | length'
Combine with security scan
stacktower parse python django --security-scan | stacktower render - --show-vulns -o django.svg

Progress indicators and summary messages always go to stderr, so they never corrupt piped JSON.

Terminal Output

A typical parse run looks like this:

⠙ Resolving python/flask...  [42/5000]
  starlette  jinja2  markupsafe  click
✓ Resolved flask (python)   42 packages · 67 edges · depth 5 · fresh · 2.3s   → flask.json Render: stacktower render flask.json

stacktower resolve

Lightweight alternative to parse for quickly testing dependency resolution. Auto-detects the language from manifest filenames and prints a human-readable dependency tree.

stacktower resolve <manifest-file>
stacktower resolve <language> <package[@version]>

Resolve Options

| Flag | Description | | ---------------------- | ---------------------------------------------------------------------------- | | -o, --output | Write JSON to file (resolve tree still prints to stdout) | | -n, --name | Project name (for manifest parsing) | | --max-depth N | Maximum dependency depth (default: 10) | | --max-nodes N | Maximum packages to fetch (default: 5000) | | --enrich | Enrich with GitHub metadata (off by default, unlike parse) | | --dependency-scope | Dependency scope: prod_only (default) or all | | --include-prerelease | Include prerelease versions in resolution | | --runtime-version | Target runtime version for marker evaluation | | --no-cache | Disable caching |

Resolve Examples

# Auto-detect language from filename
stacktower resolve poetry.lock
stacktower resolve Cargo.lock
stacktower resolve package-lock.json
stacktower resolve go.mod
Resolve from registry
stacktower resolve python fastapi
stacktower resolve rust serde@1.0.195
Save resolution as JSON for rendering
stacktower resolve poetry.lock -o deps.json
stacktower render deps.json -o deps.svg

Output:

fastapi 0.104.1
  starlette 0.27.0
    anyio 4.0.0
      sniffio 1.3.0
  pydantic 2.5.2
    pydantic-core 2.14.5
    typing-extensions 4.8.0
Resolved 7 packages (max depth: 3, direct: 2)

resolve vs parse

| | resolve | parse | | --- | --- | --- | | Language detection | Auto-detected from filename | Auto-detected from filename (or explicit language subcommand) | | Default output | Human-readable tree | TTY: summary/tree, piped stdout: graph JSON | | Metadata enrichment | Off (opt-in with --enrich) | On by default (--enrich=false to skip) | | Best for | Local testing, inspecting deps | Rendering pipeline, CI |

stacktower list

List all available versions of a package from its registry. Requires a language subcommand:

stacktower list <language> <package> [flags]

List Options

| Flag | Description | | ---------------------- | --------------------------------------------------------------------- | | --all | Show all versions (default: newest 20) | | --limit N | Show the newest N versions (default: 20; ignored when --all is set) | | --runtime-version | Filter versions compatible with a specific runtime (e.g., 3.8) | | --supported-runtimes | Display runtime constraint for each version | | --no-cache | Bypass cached version data |

List Examples

stacktower list python fastapi
stacktower list rust serde
stacktower list javascript react
stacktower list go github.com/gin-gonic/gin
Show all versions
stacktower list python django --all
Filter by Python version compatibility
stacktower list python fastapi --runtime-version 3.8
Show runtime requirements for each version
stacktower list python fastapi --supported-runtimes

Output:

fastapi  python · 277 versions
  latest   0.129.2
0.129.1   0.129.0   0.128.8   0.128.7   0.128.6   0.128.5   0.128.4   0.128.3   0.128.2   0.128.1   0.128.0   0.127.1   0.127.0   0.126.0   0.125.0   0.124.4   0.124.3   0.124.2   0.124.1   0.124.0
… 256 older versions not shown (use --all to list all)

stacktower render

Generate visualizations from parsed JSON graphs. This is a shortcut that combines layout and visualize in one step.

stacktower render <graph.json|-> [flags]

Use - to read graph JSON from stdin.

Render Options

| Flag | Description | | ------------------ | ------------------------------------------------------------------------ | | -o, --output | Output file or base path for multiple formats | | -t, --type | Visualization type: tower (default), nodelink | | -f, --format | Output format(s): svg (default), json, pdf, png (comma-separated)| | --normalize | Apply graph normalization (default: true) | | --show-vulns | Show vulnerability severity colours (default: true) | | --show-licenses | Show license compliance indicators — copyleft/unknown borders (default: true) | | --flags-on-top | Render security flags on top of all blocks (default: true) | | --no-cache | Disable caching |

Tower-Specific Options

| Flag | Description | | --------------------------------- | --------------------------------------------------------------------- | | --width N | Frame width in pixels (default: 800) | | --height N | Frame height in pixels (default: 600) | | --style handdrawn\|simple | Visual style (default: handdrawn) | | --randomize | Vary block widths to visualize load-bearing structure (default: true) | | --merge | Merge subdivider blocks into continuous towers (default: true) | | --popups | Enable hover popups with package metadata (default: true) | | --nebraska | Show "Nebraska guy" maintainer ranking panel | | --edges | Show dependency edges as dashed lines | | --ordering optimal\|barycentric | Crossing minimization algorithm (default: optimal) | | --ordering-timeout N | Timeout for optimal search in seconds (default: 60) |

Render Examples

# Basic tower rendering (XKCD-style)
stacktower render flask.json -o flask.svg
Clean style without hand-drawn effects
stacktower render serde.json --style simple --randomize=false --popups=false -o serde.svg
Node-link diagram (uses Graphviz DOT layout)
stacktower render yargs.json -t nodelink -o yargs.svg
With Nebraska maintainer rankings
stacktower render flask.json --nebraska -o flask.svg
Multiple output formats
stacktower render flask.json -f svg,pdf,png -o flask
Large graph with faster ordering
stacktower render big-project.json --ordering barycentric -o big.svg
Custom dimensions
stacktower render flask.json --width 1200 --height 900 -o flask-large.svg
Show dependency edges
stacktower render flask.json --edges -o flask-edges.svg
Disable vulnerability colours
stacktower render scanned.json --show-vulns=false -o clean.svg

Output Formats

Output path behavior:

• No -o: Derives from input (input.json → input.<format>)
• Single format: Uses exact path (-o out.svg → out.svg)
• Multiple formats: Strips extension, adds format (-o out -f svg,json → out.svg, out.json)

Note: PDF and PNG output requires librsvg:

- macOS: brew install librsvg

- Linux: apt install librsvg2-bin

Two-Step Workflow

For more control, run layout and visualize separately:

stacktower layout flask.json -o flask.layout.json
stacktower visualize flask.layout.json -o flask.svg

stacktower layout

Compute visualization layout from a dependency graph. Outputs a layout JSON that can be rendered separately with visualize.

stacktower layout <graph.json> [flags]

Layout Options

| Flag | Description | | --------------------------------- | --------------------------------------------------------------------- | | -o, --output | Output file (default: <input>.layout.json) | | -t, --type | Visualization type: tower (default), nodelink | | --normalize | Apply graph normalization (default: true) | | --width N | Frame width in pixels (default: 800) | | --height N | Frame height in pixels (default: 600) | | --style | Visual style: handdrawn (default), simple | | --ordering | Ordering algorithm: optimal (default), barycentric | | --ordering-timeout N | Timeout for optimal search in seconds (default: 60) | | --randomize | Randomize block widths (tower, default: true) | | --merge | Merge subdivider blocks (tower, default: true) | | --nebraska | Show Nebraska maintainer ranking (tower) | | --show-vulns | Show vulnerability colours (default: true) | | --show-licenses | Show license indicators (default: true) | | --flags-on-top | Render security flags on top of all blocks (default: true) | | --no-cache | Disable caching |

stacktower visualize

Render visualization from a computed layout (produced by layout).

stacktower visualize <layout.json> [flags]

Visualize Options

| Flag | Description | | ------------------ | ------------------------------------------------------------------------ | | -o, --output | Output file or base path for multiple formats | | -f, --format | Output format(s): svg (default), json, pdf, png (comma-separated)| | --style | Visual style: handdrawn (default), simple | | --edges | Show dependency edges (tower) | | --popups | Show hover popups with metadata (default: true) | | --show-vulns | Show vulnerability colours (default: true) | | --show-licenses | Show license indicators (default: true) | | --flags-on-top | Render security flags on top of all blocks (default: true) | | --no-cache | Disable caching |

stacktower cache

Manage the local cache (~/.cache/stacktower/).

stacktower cache clear    # Delete all cached entries
stacktower cache path     # Print cache directory path
stacktower cache stats    # Show entry count, size, and age (alias: cache info)

# Check cache statistics
stacktower cache stats
Clear the cache before a fresh run
stacktower cache clear
stacktower parse python requests -o requests.json
Get cache path for scripting
CACHE_DIR=$(stacktower cache path)

stacktower why

Find all dependency paths from the root to a target package. Answers "why is this package in my dependency tree?"

stacktower why <graph.json|-> <package> [package...] [flags]

Why Options

| Flag | Description | | ---------------- | ---------------------------------------------------- | | -f, --format | Output format: text (default), json | | -o, --output | Output file (stdout if omitted) | | --max-paths N | Maximum paths to display per target (default: 10) | | --shortest | Show only the shortest path(s) |

Why Examples

stacktower why flask.json markupsafe
stacktower why flask.json markupsafe -f json
stacktower why flask.json markupsafe --shortest
Multiple targets
stacktower why flask.json markupsafe click jinja2
Piped from parse
stacktower parse python flask | stacktower why - markupsafe

Output:

markupsafe 3.0.3
flask → markupsafe   flask → jinja2 → markupsafe   flask → werkzeug → markupsafe
3 paths found (shortest: depth 1)

stacktower stats

Produce a dependency health report from a parsed graph. Answers "how healthy is my dependency tree?"

stacktower stats <graph.json|-> [flags]

Stats Options

| Flag | Description | | ---------------- | ----------------------------------- | | -f, --format | Output format: text (default), json | | -o, --output | Output file (stdout if omitted) |

Stats Examples

stacktower stats flask.json
stacktower stats flask.json -f json
Piped from parse (with security scan for vuln data)
stacktower parse python flask --security-scan | stacktower stats -

Go deeper with Triage AI: Stacktower Cloud can run an AI agent that clones your repo, analyzes how you actually use each dependency, and produces a prioritized health grade (A-F) with actionable recommendations.

Output:

flask 3.1.3  ·  python
Overview   8 packages · 9 edges · depth 2   6 direct · 1 transitive
Maintenance   3 single-maintainer packages (43%)   1 brittle packages: pycparser   Median last commit: 47 days ago
Licenses   7 permissive (MIT: 4, Apache-2.0: 2, BSD-3-Clause: 1)   1 unknown
Vulnerabilities   0 critical · 1 high · 2 medium · 0 low   Affected: werkzeug (high), jinja2 (medium)
Top load-bearing packages (most reverse dependencies)   1. markupsafe           — 3 dependents   2. typing-extensions    — 2 dependents

stacktower diff

Compare two dependency graphs and report what changed: added, removed, updated packages, and new vulnerabilities.

stacktower diff <before.json> <after.json|-> [flags]

Diff Options

| Flag | Description | | ------------------ | -------------------------------------------------- | | -f, --format | Output format: text (default), json | | -o, --output | Output file (stdout if omitted) | | --fail-on-vuln | Exit 3 if new vulnerabilities were introduced (CI) |

Diff Examples

# Compare two saved graphs
stacktower diff flask-old.json flask.json
stacktower diff flask-old.json flask.json -f json
Pipe the "new" graph from stdin
stacktower parse python flask | stacktower diff flask-old.json -
Fail in CI if new vulnerabilities appear
stacktower diff old.json new.json --fail-on-vuln

Automate this on every PR: The Stacktower GitHub Action runs diff automatically, posts before/after tower images as a PR comment, and can block merges on new vulnerabilities or license issues.

Output:

flask  2.0.0 → 3.1.3
1 added    - 0 removed    ~ 2 updated    = 5 unchanged

Added
  + blinker 1.9.0
Updated   ~ flask                2.0.0 → 3.1.3   ~ jinja2               3.1.2 → 3.1.6

stacktower sbom

Export the dependency graph as a standards-compliant Software Bill of Materials in CycloneDX or SPDX format.

stacktower sbom <graph.json|-> [flags]

SBOM Options

| Flag | Description | | ------------------ | -------------------------------------------------------- | | -f, --format | SBOM format: cyclonedx (default), spdx | | -o, --output | Output file (stdout if omitted) | | --encoding | Serialization: json (default), xml (CycloneDX only) | | --spec-version | Specification version (default: latest supported) |

SBOM Examples

# CycloneDX (default)
stacktower sbom flask.json -o flask.cdx.json
stacktower sbom flask.json -f cyclonedx --encoding xml -o flask.cdx.xml
SPDX
stacktower sbom flask.json -f spdx -o flask.spdx.json
Piped from parse (with security scan for vuln data in SBOM)
stacktower parse python flask --security-scan | stacktower sbom - -o flask.cdx.json

The generated SBOM includes package identifiers (purls), license data, dependency relationships, and vulnerability findings when the graph was parsed with --security-scan.

stacktower github

GitHub authentication and app installation commands.

stacktower github login       # Authenticate with GitHub (device flow)
stacktower github logout      # Remove stored credentials
stacktower github whoami      # Show current session and app installation status
stacktower github install     # Install/configure the GitHub App for repo access
stacktower github uninstall   # Uninstall the GitHub App (opens settings page)

# Login (opens browser for device authorization)
stacktower github login
Install the GitHub App to grant access to your repositories
stacktower github install
Verify session and check app installation
stacktower github whoami
Parse from GitHub (auto-prompts login if needed)
stacktower parse github owner/repo -o deps.json

Note: To access private repositories, install the Stacktower GitHub App

and grant it access to the specific repos you want to analyze.

stacktower info

Display version, supported languages, registries, and manifest filenames.

stacktower info

Output:

stacktower v1.0.0 (abc1234, 2024-01-15)
Commit abc1234
Built  2024-01-15
Supported Languages   python     registry: pypi.org     manifests: poetry.lock, pyproject.toml, requirements.txt, uv.lock   rust       registry: crates.io     manifests: Cargo.lock, Cargo.toml   javascript registry: registry.npmjs.org     manifests: package-lock.json, package.json   ...
Docs: https://app.stacktower.io/cli-docs

stacktower version

Show version and build information.

stacktower version

stacktower completion

Generate shell completion scripts.

stacktower completion bash
stacktower completion zsh
stacktower completion fish
stacktower completion powershell

Completion Setup

# Bash (Linux)
stacktower completion bash > /etc/bash_completion.d/stacktower
Bash (macOS with Homebrew)
stacktower completion bash > $(brew --prefix)/etc/bash_completion.d/stacktower
Zsh
stacktower completion zsh > "${fpath[1]}/_stacktower"
Fish
stacktower completion fish > ~/.config/fish/completions/stacktower.fish

Included Examples

The repository ships with pre-parsed graphs and manifest files so you can experiment immediately:

# Real packages with full metadata (XKCD-style by default)
stacktower render examples/real/flask.json -o flask.svg
stacktower render examples/real/serde.json -o serde.svg
stacktower render examples/real/yargs.json -o yargs.svg
With Nebraska guy maintainer ranking
stacktower render examples/real/flask.json --nebraska -o flask.svg
Synthetic test cases for layout algorithm testing
stacktower render examples/test/diamond.json -o diamond.svg
stacktower render examples/test/crossing.json -o crossing.svg

Note: For accurate Nebraska rankings, parse with --contributors to fetch maintainer data:

> stacktower parse python flask --contributors -o flask.json

Example Manifest & Lock Files

The examples/manifest/ directory contains sample manifest and lock files for every supported ecosystem, useful for testing resolve and parse locally:

| File | Language | Type | | --- | --- | --- | | poetry.lock | Python | Lock file | | uv.lock | Python | Lock file | | pyproject.toml | Python | Manifest | | requirements.txt | Python | Manifest | | package-lock.json | JavaScript | Lock file | | package.json | JavaScript | Manifest | | Cargo.lock | Rust | Lock file | | Cargo.toml | Rust | Manifest | | Gemfile.lock | Ruby | Lock file | | Gemfile | Ruby | Manifest | | composer.lock | PHP | Lock file | | composer.json | PHP | Manifest | | go.mod | Go | Manifest | | pom.xml | Java | Manifest |

stacktower resolve examples/manifest/poetry.lock
stacktower resolve examples/manifest/Cargo.lock
stacktower resolve examples/manifest/package-lock.json

JSON Format

The render layer accepts a simple JSON format, making it easy to visualize any directed graph—not just package dependencies. You can hand-craft graphs for component diagrams, callgraphs, or pipe output from other tools.

Minimal Example

{
  "nodes": [{ "id": "app" }, { "id": "lib-a" }, { "id": "lib-b" }],
  "edges": [
    { "from": "app", "to": "lib-a" },
    { "from": "lib-a", "to": "lib-b" }
  ]
}

Required Fields

| Field | Type | Description | | -------------- | ------ | ------------------------------------------- | | nodes[].id | string | Unique node identifier (displayed as label) | | edges[].from | string | Source node ID | | edges[].to | string | Target node ID |

Optional Fields

| Field | Type | Description | | ------------------------ | ------ | ------------------------------------------------------------------ | | nodes[].row | int | Pre-assigned layer (computed automatically if omitted) | | nodes[].kind | string | Internal use: "subdivider" or "auxiliary" | | nodes[].vuln_severity | string | Max vulnerability severity: critical, high, medium, or low | | nodes[].meta | object | Freeform metadata for display features |

Recognized meta Keys

These keys are read by specific render flags. All are optional—missing keys simply disable the corresponding feature.

| Key | Type | Used By | | ------------------- | ------------- | ------------------------------------------ | | repo_url | string | Clickable blocks, --popups, --nebraska | | repo_stars | int | --popups | | repo_owner | string | --nebraska | | repo_maintainers | []string | --nebraska | | repolastcommit | string (date) | --popups, brittle detection | | repolastrelease | string (date) | --popups | | repo_archived | bool | --popups, brittle detection | | summary | string | --popups (fallback: description) | | vuln_severity | string | --show-vulns (severity colour coding) |

Troubleshooting

| Symptom | Cause | Fix | | --- | --- | --- | | rate limited: too many requests | GitHub/PyPI API rate limit exceeded | Set GITHUB_TOKEN; use --no-cache sparingly | | librsvg / rsvg-convert errors | Missing system dependency for PDF/PNG | Install librsvg: brew install librsvg (macOS), apt install librsvg2-bin (Linux) | | Very slow for large graphs | Graph exceeds default limits | Lower --max-nodes or --max-depth; use --ordering barycentric for faster layout | | context deadline exceeded | Ordering search timeout | Increase --ordering-timeout or switch to --ordering barycentric | | No colours in output | Terminal doesn't support ANSI or NOCOLOR is set | Unset NOCOLOR; check terminal supports 256 colours |

Exit Codes

Stacktower uses stable exit codes for automation and CI:

| Code | Meaning | | --- | --- | | 0 | Success | | 1 | Runtime/system failure (network, registry/API, render/pipeline errors) | | 2 | Invalid usage or input (unsupported language, invalid package/manifest arguments) | | 3 | New vulnerabilities detected (diff --fail-on-vuln) | | 130 | Interrupted (Ctrl+C / termination signal) |

How It Works

• Parse — Fetch package metadata from registries or local manifest files
• Scan (optional) — Query OSV.dev for known vulnerabilities and annotate nodes by severity
• Analyze (optional) — Trace dependency paths (why), compute health stats (stats), diff graphs (diff), or export SBOM (sbom)
• Reduce — Remove transitive edges to show only direct dependencies
• Layer — Assign each package to a row based on its depth
• Order — Minimize edge crossings using branch-and-bound with PQ-tree pruning
• Layout — Compute block widths proportional to downstream dependents
• Render — Generate output in SVG, JSON, PDF, or PNG format, with vulnerability colours when available

Environment Variables

| Variable | Description | | --------------------- | ---------------------------------------------------------------- | | GITHUB_TOKEN | GitHub API token for metadata enrichment | | STACKTOWERGITHUBAPPCLIENTID | GitHub App client ID for device-flow auth; overrides embedded release metadata | | STACKTOWERGITHUBAPP_SLUG | GitHub App slug for install links; overrides embedded release metadata | | XDGCACHEHOME | Override default cache directory (~/.cache) | | NOCOLOR | Disable colour output (honored via termenv; see https://no-color.org) |

import (
    "github.com/stacktower-io/stacktower/pkg/core/dag"
    "github.com/stacktower-io/stacktower/pkg/core/dag/transform"
    "github.com/stacktower-io/stacktower/pkg/core/render/tower/layout"
    "github.com/stacktower-io/stacktower/pkg/core/render/tower/sink"
)
// Build a graph g := dag.New(nil) g.AddNode(dag.Node{ID: "app", Row: 0}) g.AddNode(dag.Node{ID: "lib", Row: 1}) g.AddEdge(dag.Edge{From: "app", To: "lib"})
// Normalize and render ,  = transform.Normalize(g) l := layout.Build(g, 800, 600) svg := sink.RenderSVG(l, sink.WithGraph(g), sink.WithPopups())

make install-tools  # Install required tools (golangci-lint, goimports, govulncheck)
make check          # Run local quality checks (fmt, lint, test, vuln)
make build          # Build binary to bin/stacktower