Resend CLI

The official CLI for Resend.

Built for humans, AI agents, and CI/CD pipelines.

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Install

cURL

curl -fsSL https://resend.com/install.sh | bash

Node.js

npm install -g resend-cli

Homebrew (macOS / Linux)

brew install resend/cli/resend

PowerShell (Windows)

irm https://resend.com/install.ps1 | iex

Or download the .exe directly from the GitHub releases page.

Local development

Use this when you want to change the CLI and run your build locally.

Prerequisites

• Node.js 20+

Setup

1. Clone the repo

   git clone https://github.com/resend/resend-cli.git
   cd resend-cli

2. Install dependencies

   pnpm install

3. Build locally

   pnpm build

   Output: ./dist/cli.cjs

Running the CLI locally

Use the dev script:

pnpm dev -- --version

Or run the built JS bundle:

node dist/cli.cjs --version

Making changes

After editing source files, rebuild:

pnpm build

Building native binaries

To build a standalone native binary:

pnpm build:bin

Output: ./dist/resend

Quick start

# Authenticate
resend login

# Send an email
resend emails send \
  --from "[email protected]" \
  --to [email protected] \
  --subject "Hello from Resend CLI" \
  --text "Sent from my terminal."

# Check your environment
resend doctor

Authentication

The CLI resolves your API key using the following priority chain:

| Priority | Source | How to set | |----------|--------|------------| | 1 (highest) | --api-key flag | resend --api-key re_xxx emails send ... | | 2 | RESEND_API_KEY env var | export RESEND_API_KEY=re_xxx | | 3 (lowest) | Config file | resend login |

If no key is found from any source, the CLI errors with code auth_error.

Commands

resend login

Authenticate by storing your API key locally. The key is validated against the Resend API before being saved.

resend login

Interactive mode (default in terminals)

When run in a terminal, the command checks for an existing key:

• No key found — Offers to open the Resend API keys dashboard in your browser so you can create one, then prompts for the key.
• Existing key found — Shows the key source (env, config) and prompts for a new key to replace it.

The key is entered via a masked password input and must start with re_.

Non-interactive mode (CI, pipes, scripts)

When stdin is not a TTY, the --key flag is required:

resend login --key re_xxxxxxxxxxxxx

Omitting --key in non-interactive mode exits with error code missing_key.

Options

| Flag | Description | |------|-------------| | --key <key> | API key to store (required in non-interactive mode) |

Output

On success, credentials are saved to ~/.config/resend/credentials.json with 0600 permissions (owner read/write only). The config directory is created with 0700 permissions.

# JSON output
resend login --key re_xxx --json
# => {"success":true,"config_path":"/Users/you/.config/resend/credentials.json"}

Error codes

| Code | Cause | |------|-------| | missing_key | No --key provided in non-interactive mode | | invalid_key_format | Key does not start with re_ | | validation_failed | Resend API rejected the key |

Switch between teams and accounts

If you work across multiple Resend teams or accounts, the CLI handles that too.

Switch between profiles without logging in and out:

resend auth switch

You can also use the global --profile (or -p) flag on any command to run it with a specific profile.

resend domains list --profile production

resend emails send

Send an email via the Resend API. Provide all options via flags for scripting, or let the CLI prompt interactively for missing fields.

resend emails send \
  --from "Name <[email protected]>" \
  --to [email protected] \
  --subject "Subject line" \
  --text "Plain text body"

Options

| Flag | Required | Description | |------|----------|-------------| | --from <address> | Yes | Sender email address (must be from a verified domain) | | --to <addresses...> | Yes | One or more recipient email addresses (space-separated) | | --subject <subject> | Yes | Email subject line | | --text <text> | One of text/html/html-file | Plain text body | | --html <html> | One of text/html/html-file | HTML body as a string | | --html-file <path> | One of text/html/html-file | Path to an HTML file to use as body | | --cc <addresses...> | No | CC recipients (space-separated) | | --bcc <addresses...> | No | BCC recipients (space-separated) | | --reply-to <address> | No | Reply-to email address |

Interactive mode

When run in a terminal without all required flags, the CLI prompts for missing fields:

# prompts for from, to, subject, and body
resend emails send

# prompts only for missing fields
resend emails send --from "[email protected]"

Non-interactive mode

When piped or run in CI, all required flags must be provided. Missing flags cause an error listing what's needed:

echo "" | resend emails send --from "[email protected]"
# Error: Missing required flags: --to, --subject

A body (--text, --html, or --html-file) is also required — omitting all three exits with code missing_body.

Examples

Multiple recipients:

resend emails send \
  --from "[email protected]" \
  --to [email protected] [email protected] \
  --subject "Team update" \
  --text "Hello everyone"

HTML from a file:

resend emails send \
  --from "[email protected]" \
  --to [email protected] \
  --subject "Newsletter" \
  --html-file ./newsletter.html

With CC, BCC, and reply-to:

resend emails send \
  --from "[email protected]" \
  --to [email protected] \
  --subject "Meeting notes" \
  --text "See attached." \
  --cc [email protected] \
  --bcc [email protected] \
  --reply-to [email protected]

Overriding the API key for one send:

resend --api-key re_other_key emails send \
  --from "[email protected]" \
  --to [email protected] \
  --subject "Test" \
  --text "Using a different key"

Output

Returns the email ID on success:

{ "id": "49a3999c-0ce1-4ea6-ab68-afcd6dc2e794" }

Error codes

| Code | Cause | |------|-------| | auth_error | No API key found or client creation failed | | missing_body | No --text, --html, or --html-file provided | | file_read_error | Could not read the file passed to --html-file | | send_error | Resend API returned an error |

resend doctor

Run environment diagnostics. Verifies your CLI version, API key, domains, and detects AI agent integrations.

resend doctor

Checks performed

| Check | Pass | Warn | Fail | |-------|------|------|------| | CLI Version | Running latest | Update available or registry unreachable | — | | API Key | Key found (shows masked key + source) | — | No key found | | Domains | Verified domains exist | No domains or all pending verification | API key invalid | | AI Agents | Lists detected agents (or none) | — | — |

The API key is always masked in output (e.g. re_...xxxx).

Interactive mode

In a terminal, shows animated spinners for each check with colored status icons:

  Resend Doctor

  ✔ CLI Version: v0.1.0 (latest)
  ✔ API Key: re_...xxxx (source: env)
  ✔ Domains: 2 verified, 0 pending
  ✔ AI Agents: Detected: Cursor, Claude Desktop

JSON mode

resend doctor --json

{
  "ok": true,
  "checks": [
    { "name": "CLI Version", "status": "pass", "message": "v0.1.0 (latest)" },
    { "name": "API Key", "status": "pass", "message": "re_...xxxx (source: env)" },
    { "name": "Domains", "status": "pass", "message": "2 verified, 0 pending" },
    { "name": "AI Agents", "status": "pass", "message": "Detected: Cursor" }
  ]
}

Each check has a status of pass, warn, or fail. The top-level ok is false if any check is fail.

Detected AI agents

| Agent | Detection method | |-------|-----------------| | OpenClaw | ~/clawd/skills directory exists | | Cursor | ~/.cursor directory exists | | Claude Desktop | Platform-specific config file exists | | VS Code | .vscode/mcp.json in current directory |

Exit code

Exits 0 when all checks pass or warn. Exits 1 if any check fails.

Global options

These flags work on every command and are passed before the subcommand:

resend [global options] <command> [command options]

| Flag | Description | |------|-------------| | --api-key <key> | Override API key for this invocation (takes highest priority) | | -p, --profile <name> | Profile to use (overrides RESEND_PROFILE env var) | | --json | Force JSON output even in interactive terminals | | -q, --quiet | Suppress spinners and status output (implies --json) | | --version | Print version and exit | | --help | Show help text |

Output behavior

The CLI has two output modes:

| Mode | When | Stdout | Stderr | |------|------|--------|--------| | Interactive | Terminal (TTY) | Formatted text | Spinners, prompts | | Machine | Piped, CI, or --json | JSON | Nothing |

Switching is automatic — pipe to another command and JSON output activates:

resend doctor | jq '.checks[].name'
resend emails send --from ... --to ... --subject ... --text ... | jq '.id'

Error output

Errors always exit with code 1 and output structured JSON to stdout:

{ "error": { "message": "No API key found", "code": "auth_error" } }

Agent & CI/CD usage

CI/CD

Set RESEND_API_KEY as an environment variable — no resend login needed:

# GitHub Actions
env:
  RESEND_API_KEY: ${{ secrets.RESEND_API_KEY }}
steps:
  - run: |
      resend emails send \
        --from "[email protected]" \
        --to "[email protected]" \
        --subject "Deploy complete" \
        --text "Version ${{ github.sha }} deployed."

AI agents

Agents calling the CLI as a subprocess automatically get JSON output (non-TTY detection). The contract:

• Input: All required flags must be provided (no interactive prompts)
• Output: JSON to stdout, nothing to stderr
• Exit code: 0 success, 1 error
• Errors: Always include message and code fields

Configuration

| Item | Path | Notes | |------|------|-------| | Config directory | ~/.config/resend/ | Respects $XDG_CONFIG_HOME on Linux, %APPDATA% on Windows | | Credentials | ~/.config/resend/credentials.json | 0600 permissions (owner read/write) | | Install directory | ~/.resend/bin/ | Respects $RESEND_INSTALL |

License

MIT