CLI

@millionsend/cli moves an email account to MepMail — Cloud or your own instance. It reads the source provider, diffs it against the target, applies the difference and writes a report. Only Resend is a source today.

Install

Node 18 or newer, no dependencies. Run it without installing:

npx @millionsend/cli migrate --from resend

Or install it once:

npm install -g @millionsend/cli
millionsend --version

Commands

millionsend migrate --from resend                          # connect, choose resources, plan, confirm, apply, summary
millionsend migrate plan --from resend [--out plan.json]   # read-only; exit 0 nothing to do, 2 changes, 1 error
millionsend migrate apply [plan.json] [--yes]              # apply a saved plan, or plan and apply in one go
millionsend migrate status                                 # what the last run created and what is left
millionsend migrate rollback [--yes]                       # delete only what this tool created
millionsend --help | --version

• migrate is the interactive path: it asks for what it is missing (keys, target URL), lets you pick resources with a checkbox list (all checked by default except sent broadcasts), shows the plan, asks for confirmation, applies it and prints the summary.
• migrate plan reads both sides and prints what would change without writing anything to the target. --out plan.json saves it. Before any write, the plan checks the target's GET /usage — plan, limits, cloud flag — and says precisely what does not fit ("7 domains to create; the Free plan allows 3"), plus an estimate: "~2,140 requests · about 4 min at 8 req/s".
• migrate apply applies a saved plan, or plans and applies in one go. Conflicts are resolved the same way on every run: contacts are upserted by email; topics, segments, properties, webhooks, templates and domains are matched by name, key, endpoint or alias and updated when their fields differ, left unchanged when they match.
• migrate status prints what the last run created and what is left on the checklist. Needs no credentials.
• migrate rollback deletes only the ids the tool created — never rows it merely updated — in reverse dependency order, after printing the list and asking for confirmation (--yes skips it). Deleting contacts is one request per contact; the prompt shows the time estimate.

Flags

Resource names for --only and --skip, in apply order: domains, properties, topics, segments, contacts, broadcasts, templates, webhooks, suppressions, enrichment, api-keys.

Environment

Each key is resolved in this order: environment variable, then the -stdin flag, then the argument flag, then — in a terminal — a masked prompt. The target URL comes from MILLIONSEND_BASE_URL or --to-url; with neither set, a terminal offers a choice between MepMail Cloud and a self-hosted URL, and a non-interactive run targets MepMail Cloud, like the SDKs.

Files

Written next to where you run the tool, mode 0600, never containing a key:

.millionsend/ is appended to .gitignore when one exists in the current directory; the tool says so once.

Security model

• Read-only against the source. Every request to Resend is a GET to a documented endpoint, sent with the User-Agent millionsend-cli/<version>. Writes go to your MepMail API only.
• Keys stay in memory. They are never written to any file and are redacted from every log line (re_…, ms_…, whsec_… and Authorization headers).
• Two hosts, no third party. The tool contacts api.resend.com and the MepMail API URL you named. No telemetry, no update check.
• 401 or 403 from either side stops the run. No retry, no workaround.
• Rate limits are respected. 429s wait for retry-after; 5xx and network errors back off exponentially, 5 attempts. Every retry is logged.
• Opt-outs are preserved. unsubscribed and topic opt-outs are carried over as they are; the tool never re-subscribes anyone. Suppressions keep their origin (bounce, complaint, manual).

Exit codes

Non-interactive and CI

When stdin is not a terminal — or with --non-interactive or --json — the tool never prompts: a missing input exits 1 with the env var or flag to set. Pass keys through the environment or stdin, never as arguments:

export RESEND_API_KEY=re_...
export MILLIONSEND_API_KEY=ms_...
export MILLIONSEND_BASE_URL=https://api-mepmail.je4ndev.com   # or your instance's URL

millionsend migrate plan --from resend --out plan.json
# exit 2 when there is something to apply
millionsend migrate apply plan.json --yes

Or on stdin, first line source, second line target:

printf '%s\n%s\n' "$RESEND_KEY" "$MS_KEY" | millionsend migrate plan --from resend --from-key-stdin --to-key-stdin --to-url https://api.your-instance

Progress is printed one line per step (✓, ✗, ⟳ with n/N counters), appended when piped, rewritten in place in a terminal.

--json

With --json, stdout carries only JSON — the plan for migrate plan, the report for migrate apply — and progress goes to stderr, so the output can be piped into jq or saved as an artifact. --json implies --non-interactive.

millionsend migrate plan --from resend --json | jq '.counts'

Resend is a registered trademark of Plus Five Five, Inc. MepMail is not affiliated with or endorsed by Resend.