Most roundups in this category list ten products, give each two sentences, and never explain the thing that actually determines whether a tool will work for you: these products are built on fundamentally different mechanics, and picking the wrong kind matters far more than picking the wrong brand.
So this guide starts there, then names the tools — including the free method most people are actually using, which none of the other roundups will mention.
The five kinds of tool
1. Doing it yourself
A separate Gmail account, subscribed to each competitor, with one filter per brand routing its mail to its own label. Free, permanent, and the option most marketers are actually using instead of buying software. Use a fresh account rather than a plus-address — a good number of signup forms reject the plus sign in an email address, so you+brand@gmail.com fails partway down your list.
Good for: one or two competitors, browsing for inspiration, starting an archive tonight at no cost. Breaks down when: you pass three or four brands and the label becomes a pile you stop opening; when you need to count rather than find, because Gmail can’t tell you how anyone’s send frequency changed; and quietly, over months, because Gmail’s promotions and spam filtering is personalised to engagement — a monitoring account never opens anything, so mail drifts out of the inbox and the archive develops holes nothing warns you about.
2. Public archives
Someone subscribes their own addresses to thousands of brands and publishes what arrives. Milled is the best known and it's free. You search a brand, you read their recent campaigns.
Good for: browsing, inspiration, checking what a big consumer brand did last Black Friday. Breaks down when: the brand you care about isn't there, you want alerts, or you need anything private.
3. Curated indexes
MailCharts defined this category — roughly 2,500 hand-picked brands captured continuously, with benchmarks and lifecycle journeys ready on day one. It's genuinely the best experience in this space if your competitor is in the index.
Worth knowing before you go looking: Validity acquired Litmus in April 2025, MailCharts followed, and the self-serve plans were retired in late 2025. It's Litmus Enterprise now. We wrote up what happened and what it means separately.
Good for: ecommerce and retail benchmarking, instant history. Breaks down when: your competitors are B2B, niche, regional, or simply not on the list — there's no mechanism to add them.
4. Tracking address tools
You get a dedicated email address, subscribe it to whichever companies you choose, and their campaigns land in a searchable workspace. Owletter, SendView, Newsletrix, Reyo and CompetitorTrack all work this way.
Good for: watching a specific list of named rivals, any industry, any size. Breaks down when: you need history you don't have — your archive starts the day you subscribe, and no amount of money buys back last year.
5. Enterprise competitive intelligence platforms
Crayon and Klue monitor competitors across websites, pricing, job posts, reviews and news, and feed battlecards to sales teams. Email is a small part of a much larger product, and pricing assumes a competitive intelligence function exists at your company.
Good for: enablement teams at companies with a dedicated CI budget. Overkill when: what you actually wanted was to see what four competitors emailed this week.
The tools
We describe how each tool charges rather than quoting a figure. Prices in this category move, and several comparison articles circulating right now carry numbers wrong by a factor of three. Each name links to its own pricing page for the current figure.
A second Gmail account — free
Covered above, and worth repeating here because it belongs on any honest list: for one or two competitors it is genuinely sufficient, and it costs nothing to start this evening. Everything below exists to fix one of the ways it breaks down.
Milled — free
Public archive, large consumer brand coverage, no account needed. Start here before paying anyone if browsing is what you want.
Newsletrix — free tier, then priced by analysis volume
Charges by analyses per week rather than by competitor, which makes it hard to compare directly with anything else here — work out your actual weekly send volume first. AI analysis on each email: subject line scoring, CTA breakdown, ESP detection. Generous for occasional senders, tight if your competitors mail daily.
Owletter — flat tiers by number of sites
Long-running and deliberately narrow: capture, store, and report on send frequency changes. Tiers are generous on volume, with an unlimited plan at the top, which makes it the cheapest option in this category once you're past a handful of competitors. Free trial.
SendView — flat tiers by number of companies
Tiers scale by how many companies you track, with seats included higher up and a managed option where their team does the analysis for you. Priced above Owletter for comparable volume. The closest in shape to what MailCharts self-serve used to be. Free trial.
Panoramata — flat monthly tiers
Broadest of the mid-market options: email alongside ads, SMS, landing pages and social. Priced above the email-only tools, for correspondingly more coverage. The right answer if email is one of several channels you're monitoring rather than the whole job.
Reyo — lower end of the range
AI-summarised archive. Similar mechanics to the above with the emphasis on digesting what arrived rather than presenting it raw.
CompetitorTrack — first competitor free, then $10/month each
Ours, so weigh it accordingly. A tracking address per competitor, a shared inbox your team can annotate, and remote images blocked by default so opening a competitor's campaign doesn't fire their tracking pixel back at you.
The per-competitor model makes it the cheapest option on this page for the first few, and free at one. Past a handful, Owletter's flat tiers are better value, and we'd rather say so here than have you discover it on your second invoice.
How to choose
- Browsing for inspiration? Milled, free, first.
- A few named competitors? Per-competitor pricing is cheapest, and free at one.
- Ten or more? Owletter's flat tiers, comfortably.
- Competitors are B2B, niche or regional? Tracking address, necessarily — the curated indexes won't cover them.
- Need ads and social too? Panoramata.
- Have a CI budget and a sales team to arm? Crayon or Klue.
If you're here because your MailCharts plan went away, we've written a dedicated replacement guide that works through the switch in more detail.
One thing that applies whichever you pick: every tracking-address tool starts your archive on the day you subscribe. The cost of deferring the decision isn't the subscription fee, it's the campaigns that go out in the meantime and are gone for good.
What tracking actually tells you
Collecting competitor emails is easy. Getting something useful out of them comes down to a handful of signals worth watching deliberately rather than reading everything as it lands:
Cadence changes. A competitor going from two sends a week to five is usually the leading indicator of a launch or a quarter they're behind on. It shows up before the announcement does.
Discount depth over time. Not whether they discount, but whether 15% has quietly become 30% over six weeks. That's margin pressure you can read from the outside.
Offer scope. Sitewide versus a single category tells you whether they're clearing inventory or running a considered promotion.
The shift in what they're asking for. For B2B, a sequence moving from "read this guide" to "book a demo" says the pipeline needs filling. That's the SaaS equivalent of a discount getting deeper.
Send timing. Day of week and hour, over a quarter. Useful less for copying than for knowing which inbox you're competing with on a given morning.
Staying on the right side of it
Tracking competitor marketing email is ordinary competitive research — you're subscribing to a public mailing list the same as any customer. A few lines worth not crossing anyway:
Don't copy. Insight, not reproduction. Lifting a competitor's copy is both a legal problem and a strategic one, since you end up a slower version of them.
Don't pursue non-public information. We've seen people pose as prospective buyers of a business to get inside numbers. That's well past research.
Read the terms before creating accounts. If your competitor is a SaaS company, signing up for a trial to see their onboarding sequence is tempting, and most terms of service explicitly prohibit creating an account for competitive purposes. Subscribing to a newsletter is not the same thing as registering for a product.
Use a dedicated address, not a personal one. Partly to keep your own inbox clean, partly because a tracking address is easier to be straightforward about than a colleague's personal account.