MorningZero vs Superhuman vs Shortwave vs Spark vs Missive vs Gmail: what each costs and what its AI actually meters (checked August 2026)
Most comparisons of AI email clients are useless because they compare marketing pages. Everyone claims AI, so “has AI” tells you nothing. What actually separates these products in August 2026 is narrower and more boring: what you pay per seat, and which parts of the AI are rationed.
So this post does two things. It puts the real prices side by side — competitor figures read off each vendor’s own pricing page on 5 August 2026, and MorningZero‘s own updated on 19 August 2026 — and then says exactly what each tool meters, in the vendor’s own units.
Prices change. Every figure below has a link and a date. If you’re reading this months later, click through before deciding anything.
What each seat costs
| Product | Free plan? | Entry paid tier | Next tier | Source |
|---|---|---|---|---|
| MorningZero | No — 14-day trial, no card | Solo $19/mo — 5 mailboxes | Stack $29/mo — 15 mailboxes | MorningZero pricing |
| Superhuman | No | Starter $30/seat/mo ($25 annual)* | Business $40 ($33 annual)* | superhuman.com/mail/pricing |
| Shortwave | No — 14-day trial | Business $30/seat/mo | Premier $45, Max $120 | shortwave.com/pricing |
| Spark | Yes — Free, $0 | Plus $10/user/mo ($99/yr) | Pro $20/user/mo ($199/yr) | sparkmailapp.com/pricing |
| Missive | Yes — free plan, no card | Starter $18/user/mo ($14 annual) | Productive $30 ($24), Business $45 ($36) | missiveapp.com/pricing |
| Gmail | Yes — free for personal use | Gemini in Gmail requires a paid Workspace tier | — | Workspace pricing |
* Superhuman’s pricing page renders client-side, so it can’t be read from the raw HTML. We opened it in a browser on 4 September 2026 and read the figures directly from the page, which replaces the third-party tracker figures previously cited here. Treat them as indicative and confirm on Superhuman’s site.
Both pages open on annual billing rather than monthly, so the first figure either one shows you is the discounted one. Missive’s annual rate is 20% below the monthly prices above. Spark lists $120 and $240 a year and currently discounts them to $99 and $199, which is the $8.25 and $16.58 a month its page shows first.
One structural difference worth naming, because the table flattens it: Superhuman, Shortwave, Spark and Missive all price per seat, so a second mailbox generally means a second bill. MorningZero prices per mailbox allowance on a single subscription — 5 on Solo, 15 on Stack, extras at $3/month each with no cap — past 20 mailboxes the pricing page asks you to talk to us about a negotiated rate instead. Annual is $180 and $276, a 21% saving, which is about $15 and $23 a month.
That per-seat versus per-mailbox split is the single biggest driver of what you actually pay, so we priced it out properly: what one mailbox costs across 14 email apps at 1, 3, 5, 10 and 15 connected accounts, with the raw dataset attached.
What each one rations
This is the part that decides whether the AI is something you use freely or something you budget around. The units below are the vendors’ own.
| Product | What’s metered | Published limits (5 Aug 2026) |
|---|---|---|
| Shortwave | AI requests per day, threads per search, number of AI filters | Business: “roughly 150–300 Standard intelligence AI requests per day”, max 50 threads per AI search, 3 AI filters, 5 years AI search history. Premier: 2× usage, unlimited history, 100 threads, 10 filters. Max: 6× usage, 150 threads, 50 filters |
| Spark | AI credits, plus meeting notes counted separately | Plus: 40 AI meeting notes/month plus a monthly credit quota. Pro: unlimited meeting notes, monthly credit allowance. Free: limited preview of the AI assistant, no add-ons |
| Missive | AI credits, or bring your own key | ”Missive AI credits or BYOK”, multi-provider (Anthropic, OpenAI, Gemini). No per-request limits published on the pricing page |
| Superhuman | Not published per-request | The pricing page states no AI request limits |
| Gmail | Tier-gated rather than metered | Gemini features arrive with the paid Workspace tiers |
| MorningZero | Nothing | No credits, no request quotas, no message limits on either plan |
Shortwave deserves credit here. Publishing “150–300 requests per day” is more honest than the industry norm of saying nothing, and it tells you the shape of the product: the intelligence is the meter.
The honest read on each
Gmail is still the default for good reason — free, extremely reliable, and its spam filtering remains the benchmark. Its ceiling is structural: one account at a time. Multi-sign-in is switching, not merging, so there’s no single stream, no rule layer spanning accounts, and no cross-account view of what’s waiting on you.
Superhuman sells speed and delivers it. Keyboard-first, deliberate shortcuts, a genuinely fast feel. It’s the most expensive entry point here with no free tier, so it’s a decision you make on workflow rather than price. If sub-100ms interaction is the thing you optimise for, nothing else on this list beats it. If you’re specifically comparing against Superhuman, we went deeper here — how its per-account tabs hold up once you run three inboxes, and where MorningZero loses.
Shortwave is the most AI-forward of the group, strong at search, built Gmail-first. Because usage is quota-based, heavy days mean watching the meter — fine if your usage is bursty, irritating if it’s constant.
Spark has the most generous real free tier: Smart Inbox and unlimited email accounts at $0, with paid tiers starting at $10. It’s the friendliest on-ramp. The trade-off is configurability — bucketing rather than rules you author yourself.
Missive isn’t competing for the same job. It’s a team tool: shared inboxes, comments on threads, assignments. For a team triaging one address together it’s excellent, and BYOK is the most cost-transparent AI arrangement on this list. For one person drowning in their own mail, the collaboration machinery is weight you don’t need.
Where MorningZero is actually different
Two things, both checkable.
Nothing is metered. Every incoming message is classified, and no part of the AI draws on a quota — not the labeling, not Ask Zero, not summaries or drafting. That’s arithmetic rather than generosity: a small classification model costs a fraction of a cent per message, and the reasoning work is infrequent enough per user to absorb. The label breakdown across 2,866 classified messages shows what that model is actually sorting. Compare that with a model where the sorting draws on the same daily quota as the chat, so a heavy week spends the budget you wanted for thinking.
One login covers every account. Connect your mailboxes once — Gmail, Workspace, Outlook or Microsoft 365 — and they merge into a single stream, tagged per message, with one rule layer and one “what needs my reply” across all of them, on every device you sign into.
And the measured part, from our own production database on 5 August 2026: after we fixed our Gmail push pipeline, the three notifications that came through the push path landed 6, 8 and 6 seconds after the mail did. Two that fell back to polling took 27 and 110 seconds.
Where MorningZero loses
Publishing the section above without this one would be marketing, not comparison.
- No custom or self-hosted IMAP, and no Proton. Gmail, Workspace, Outlook and Microsoft 365 are fully supported, and hosted IMAP has since shipped for Fastmail, iCloud, Yahoo, AOL, GMX, Web.de, Zoho, Yandex and Mail.com using an app-specific password. What still isn’t supported is a custom or self-hosted IMAP server, and Proton requires Bridge running on your own machine.
- No free tier. Spark and Missive will let you run at $0 indefinitely; we won’t. There’s a 14-day trial that needs no card and holds nothing back across 2 mailboxes, and after that it’s $19.
- It’s young. Superhuman and Spark have years of polish; Missive has a decade of team-workflow depth.
- Our real-time pipeline broke and we didn’t notice for 11 days. Between 23 July and 4 August 2026, Gmail push ingestion failed on every message — 686 failed events — because one deleted message stalled our history cursor. Mail kept arriving through the 2-minute polling fallback, so nothing looked broken while notifications ran up to two minutes behind Gmail’s own. It’s fixed, and there have since been 45 consecutive successful push ingests. We wrote up exactly how one purged message stalled the cursor, because the failure mode is not in Google’s documentation. No comparison table would have caught that, and it’s worth weighing when any young product tells you it’s real-time.
- No team collaboration. If you need shared inboxes and thread assignment, that’s Missive, and we’re not pretending otherwise. Stack is a bigger mailbox allowance for one person, not a team plan.
Choosing without reading all of it
- Fastest keyboard-driven client, price not a factor → Superhuman
- AI-first Gmail and you’re fine with a daily AI quota → Shortwave
- Free, friendly, unlimited accounts on the free tier → Spark
- A team working one shared address → Missive
- One Google account, modest volume → stay on Gmail
- Several accounts in one stream, triage that isn’t metered, rules in plain English → MorningZero
Sources
Competitor figures checked 5 August 2026; MorningZero‘s own checked 19 August 2026:
- Shortwave pricing — plan prices, daily AI request ranges, per-search thread caps
- Spark pricing — free tier contents, Plus/Pro monthly and annual, meeting-note limits
- Missive pricing — per-user tiers, 20% annual discount, credits/BYOK
- Google Workspace pricing — which tiers include Gemini in Gmail
- MorningZero pricing — Solo and Stack, mailbox allowances, extra-mailbox rate
- Superhuman: pricing page (client-rendered; read in a browser on 4 September 2026)
Prices and quotas move. If you spot a stale number here, tell us and we’ll correct it with a fresh date.
Frequently asked
Which unified inbox has a genuinely free plan in August 2026?
Two of the six: Spark (Free, $0) and Missive (free plan, no card required). Gmail itself is free, but Gemini in Gmail needs a paid Workspace tier. Superhuman and Shortwave are paid-only — Shortwave offers a 14-day trial. MorningZero has no free plan either; it runs a 14-day trial that needs no card, with every feature on across 2 mailboxes, after which your mailboxes stay connected and readable and the AI stops.
Does Shortwave limit how much AI you can use?
Yes, and it publishes the numbers. As of 5 August 2026 its Business plan ($30/seat/month) lists roughly 150–300 Standard-intelligence AI requests per day, a maximum of 50 threads per AI search, and 3 AI-powered filters. Premier ($45) doubles the usage allowance and Max ($120) is 6× Business.
What does MorningZero meter?
Nothing. There are no AI credits, no request quotas and no message limits on either plan. Every incoming message is classified and every AI feature is included on both Solo and Stack; the only differences between them are how many mailboxes you can connect and priority support.
Is Superhuman's pricing published on its website?
Its pricing page renders client-side, so the figures can't be read from the raw page. We opened it in a browser on 4 September 2026 and read them directly: Starter is $30 per member a month billed monthly ($25 billed annually) and Business is $40 ($33 annually). The page opens on the annual view, so $25 and $33 are what it shows first.