The one requirement that matters: your gmail.com pool must actually sell for instagram.com. Not "in stock" — sellable.

I have already tested hero-sms, Qeex, EmailTicking and SMSBower. All four publish a gmail count for instagram.com and then refuse the purchase — hero listed 97 and declined 2,459 consecutive orders. Meanwhile all four sell gmail instantly for Discord, Reddit, Telegram and Threads. If your backend is the Kopeechka/Firstmail upstream, you have the same problem and we will both waste time.

So before anything else, please post:

• your current gmail.com stock specifically for instagram.com
• whether you will do a live test order on it

What I need:

• API: list domains with stock, buy an inbox bound to a site, poll for the code, cancel. JSON.
• gmail.com specifically (not Workspace, not your own domains, not .edu — I check)
• 30+ activations/day sustained, on Instagram
• refund or no charge when no mail arrives

Price: up to $0.04 per activation.

Private supplier is fine. Useful to state up front: own pool or reselling, and if reselling, whose.

Process: I fund a small balance, run a live Instagram test the same day, and scale immediately if it works. Crypto fine.

Not looking for: SMS/phone numbers, accounts sold outright, temp-mail on your own domains, or Outlook/GMX.

Contact: Telegram — t.me/Gr33nHorse