render-env-vars

Environment Variables on Render

Before inspecting or changing environment variables, secrets, secret files, or environment groups, read references/environment-variables.md for the current documentation, source-of-truth, safety, and mutation workflow.

Blueprint wiring examples and language-specific application notes live under references/.

When to Use This Skill

Use this skill when users want to:

• Add, change, or remove environment variables or secrets
• Understand Dashboard vs Blueprint vs API/MCP flows
• Use environment groups for shared configuration
• Wire fromDatabase, fromService, fromGroup, sync: false, or generateValue in Blueprints
• Debug missing vars, secret files, precedence, or platform-injected names

For full Blueprint authoring, pair with render-blueprints. For first-time deploys, render-deploy. For web service behavior and ports, render-web-services.

Blueprint Wiring (Summary)

After reading references/environment-variables.md, use references/wiring-reference.md for task-specific fromDatabase, fromService, and fromGroup examples. Consult render-blueprints for the complete Blueprint workflow.

Platform-Injected Variables

Use the current default-variable reference fetched through references/environment-variables.md instead of relying on a fixed catalog. Language-specific application notes remain in references/platform-variables.md.

Runtime-Specific Defaults

Always bind HTTP servers to 0.0.0.0 and PORT (or the stack’s documented port env) unless using a static site or custom Docker entrypoint.

• When diagnosing a port-binding failure, first establish whether the service uses a native runtime or Docker and inspect its actual start command; the applicable defaults differ.
• For a web service, PORT defaults to 10000. Prefer reading $PORT in the start command rather than hardcoding that number or setting PORT merely to match an arbitrary hardcoded port.
• Native Python services currently receive GUNICORN_CMD_ARGS with a default bind to 0.0.0.0:10000. A custom Gunicorn start command should bind to 0.0.0.0:$PORT so the process and Render's health checks use the same port.

Common Issues

WEB_CONCURRENCY defaults differ for some older and newer services. When debugging worker counts, compare service creation date and explicit overrides, then confirm current behavior using references/environment-variables.md and references/platform-variables.md.

References

• references/environment-variables.md — Current configuration docs, secret handling, groups, platform variables, and mutation safety
• references/wiring-reference.md — Blueprint cross-resource wiring examples and workspace edge cases
• references/platform-variables.md — Concurrency, native-runtime versus Docker behavior, and application parsing notes

Related Skills

• render-blueprints — Full Blueprint authoring, validation, multi-service layouts
• render-deploy — First deploy, repo requirements, MCP vs YAML
• render-web-services — Ports, health checks, scaling behavior tied to env-driven servers

Current documentation retrieval

Whenever this skill directs you to consult current Render documentation:

1. Retrieve the linked Markdown document directly with an available URL-fetching tool or HTTP client, such as curl. Do not substitute web-search summaries for the document.
2. Confirm that retrieval succeeded and returned the expected document, then read its contents. Saving a file or printing its path is not sufficient.
3. If the request fails or your tool cannot read the Markdown response, open and read the linked HTML version instead.
4. If neither version can be retrieved, disclose that the current reference is unavailable and follow any topic-specific fallback in the skill. Use bundled guidance only for stable constraints, and do not guess at changeable platform details.

When a task requires multiple references, apply this workflow to each one and distinguish the documents you verified from those that remain unavailable.