PayPester vs send21

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

PayPester compared with send21
Detail	PayPester	send21
What it does	Automated overdue invoice reminders that you approve before sending	Non-custodial crypto payment links and API for people and AI agents
Stage	MVP	Not given
Founded	Not given	Not given
Based in	Not given	Not given
Pricing model	Free	Paid
Pricing	Free while in beta	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.
Key features	Automatic detection of overdue invoices Three escalation levels at day 3, 14, and 30 Customizable reminder tones (Friendly, Firm, Direct) Manual approval required before sending Edit, skip, or stop reminders per invoice Read-only Stripe integration	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
What makes it different	Nothing sends until you manually approve it Reminders escalate in firmness automatically over time Secure read-only access to Stripe with no write permissions No action needed unless invoices are actually overdue	Not given
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)	Not checked yet no change since last check	6 +2 (up) since last check
Trust Flow (Majestic)	0	15
Citation Flow (Majestic)	0	28
Referring domains (Majestic)	0	35

4 details filled in for both companies.

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