send21 vs Ringup

A side-by-side comparison built from both listings. Blank cells mean the company has not given that detail; we never guess.

send21 compared with Ringup
Detail	send21	Ringup
What it does	Non-custodial crypto payment links and API for people and AI agents	Identity and payments layer for AI voice agents
Stage	Not given	Not given
Founded	Not given	Not given
Based in	Not given	US
Pricing model	Paid	Contact for pricing
Pricing	One fee per payment: 0.49% on $0-$10, 0.39% on $10-$50, 0.29% on $50-$100, 0.19% on $100-$500, 0.14% on $500-$2,000, 0.09% on $2,000-$10,000, 0.04% on $10,000-$50,000, 0.02% on $50,000-$100,000, 0.01% above $100,000. Minimum $0.01, maximum $100. No subscription, setup fee or monthly minimum.	Not given
Key features	REST API with scoped keys and batch drafts up to 25 per call Support for Bitcoin PSBT and batching wallets like Safe No KYC required, encrypted email storage only Idempotency keys for safe retries Shopify connection with custom app and setup help Fee collected separately on Ethereum and EVM chains via Safe batching	Caller recognition by phone number with saved context Integration with 144+ payment processors Support for multiple voice platforms PCI Level 1 compliant card vault storage Carrier-verified SIM swap detection for security Direct settlement to merchant's processor REST API for custom voice stacks No card numbers read aloud on calls
What makes it different	Not given	Phone number as payment identity eliminates card recitation Works with every merchant's existing processor without creating new accounts Funds never held or reconciled by Ringup
Free plan	Not given	Not given
Open source	Not given	Not given
Platforms	Not given	Not given
Public API	Not given	Not given
Community votes	0	0
DR (Domain Rating by Ahrefs)	10 +4 (up) since last check	6 no change since last check
Trust Flow (Majestic)	15	0
Citation Flow (Majestic)	28	24
Referring domains (Majestic)	35	36

3 details filled in for both companies.

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