Green API vs UltraMsg vs WaHttp: Session API Comparison

Green API, UltraMsg and WaHttp are the same category of product: a QR-linked, unofficial WhatsApp connection with a REST layer on top, no Meta approval, no templates, no 24-hour window. None of them is the architectural outlier here. What separates them is entirely the business model behind the API call, specifically how each one prices a connected number, and that number moves more than you'd expect across the three.

How each one actually prices a connection

Green API runs a free Developer plan limited to 3 chats, 100 WhatsApp-availability checks a month, and 10 status posts, enough to test an integration but not to run one. Production use requires the Business plan at $12 a month, billed per instance, with unlimited chats and 30,000 availability checks a month. Want five numbers connected? That's five separate $12 instances, $60 a month total.

UltraMsg publishes no pricing on its own site that I could verify directly; Capterra lists its price as "contact vendor" with no public rate card. A third-party comparison citing current rates puts it at $39 a month for one number and $195 for five, which works out to the same $39-per-instance rate scaled linearly. I'm flagging this clearly as a single third-party source rather than the vendor's own published figure, since I couldn't confirm it against UltraMsg's site directly; treat it as indicative and verify the current number before budgeting against it.

WaHttp prices in bundles rather than strictly per instance: $5 a month for one session, $12 for three, $22 for six, $35 for ten, with unlimited messages on every tier and no per-method request caps.

The cost gap at real scale

At one number, Green API already costs more than twice WaHttp's rate, and UltraMsg nearly eight times. The gap widens as you add numbers, because Green API and UltraMsg both charge linearly per instance while WaHttp's bundle pricing gets cheaper per session as the count goes up. For an agency or a business running several client numbers, that difference compounds into real money every month, not a rounding error.

To be fair to both: per-instance pricing isn't unreasonable as a model, and it's the more common approach across this category generally. It's simplest to understand, and if you genuinely only need one number and never plan to add more, the per-instance rate and a bundle rate converge. The gap only opens up once you're running more than a couple of numbers, which is exactly the use case, agencies and multi-number operations, that session-based APIs tend to attract in the first place.

What you get for the money, beyond the number itself

Feature-wise, all three sit close together: QR pairing, REST sending, webhook delivery for inbound events, media support. Green API's free Developer tier is a genuine advantage for evaluation, since it lets you build and test an integration before paying anything, something neither UltraMsg nor WaHttp offers in quite the same shape, WaHttp instead giving a 7-day trial capped at 100 messages a day rather than an indefinitely free limited tier.

Request-level caps are worth checking regardless of which you pick. Green API limits certain API methods like WhatsApp-availability checks even on its paid Business plan (30,000 a month), rather than capping messages themselves. If your integration leans heavily on that specific method at high volume, confirm the cap fits your usage before committing. WaHttp carries no comparable per-method request limit on any plan.

Choosing

Choose Green API if you want a genuinely free tier to build and test against before paying anything, you're running one or two numbers where the per-instance rate stays reasonable, and you don't mind the availability-check request cap on your usage pattern.

Choose UltraMsg if its specific feature set or support experience is what you need; verify the current price directly with the vendor first, since the figures here come from a third party rather than UltraMsg's own published rate card, and confirm it's still competitive before committing at the per-instance rate.

Choose WaHttp if you're running more than a couple of numbers and the per-instance pricing model elsewhere in this category is the actual pain point, since the bundle structure is built specifically to stay cheap as the session count grows.

Side by side

What neither one changes

All three connect as a linked device through WhatsApp's web protocol, outside Meta's official Business Platform, so the same terms-of-service exposure applies regardless of which one's dashboard you're looking at. Pricing model doesn't change ban risk; sending behavior and volume do. Our Green API alternative post and UltraMsg alternative post each go deeper into the specific trade-offs of those two platforms individually, and our full provider comparison covers the wider field if none of these three turns out to be the right fit.

Migration notes

All three expose a broadly similar REST shape, sessions, send endpoints, webhook delivery, so moving between them is mostly a matter of remapping field names and re-pairing each number by QR code rather than a structural rewrite. Confirm each platform's webhook payload format before cutting over, since delivery-receipt and inbound-message shapes differ in naming even where the underlying events are the same, and double-check any method-level request caps against your actual call volume before you commit to a new provider's limits.