Aurinko is the quiet one in the unified mailbox API category, and it deserves more attention than it gets. It covers the same four data surfaces Horato covers and adds a CRM layer nobody else in the category offers, at the lowest entry price of any API vendor. What separates the two products is the bet each one makes past that overlap.
What Aurinko is and who it's for
Aurinko is a unified API over email, calendar, contacts, and tasks, with scheduling APIs, webhooks, and a direct pass-through API for the moments when a normalized layer gets in your way. Provider coverage goes past the usual pair: Google, Office 365, Exchange including EWS, Zoho, iCloud, and consumer Microsoft mailboxes.
The distinctive piece is CRM. BrightSync syncs email and calendar into CRM systems at $2 to $4 per user, and a virtualized CRM API gives you one interface over Salesforce, HubSpot, and others. If your product lives next to a CRM, that layer can replace a real chunk of integration work, and no other vendor in this comparison has an answer to it.
Where Aurinko shines
The strengths are concrete and easy to verify on its pricing page.
- The lowest per-account price among the API vendors. Plans start at $1 per account per month for accounts moving under 1GB of data.
- A tasks API, which most of the category still treats as an afterthought.
- CRM depth through BrightSync and the virtualized CRM API, with Salesforce, HubSpot, and other systems behind one interface.
- Coverage for Zoho, iCloud, and Exchange environments that still run EWS.
Where the two products actually differ
On the four core surfaces the products are close, so the differences live at the edges. Aurinko goes wider on providers and deeper on CRM. Horato stays with Google and Microsoft accounts and spends the effort elsewhere. Booking pages are white-label and run on your own domain. Webhooks are signed, with every delivery logged. Agent tools over MCP sit behind an approval gate, and every run is recorded for review.
Recording is the clearest gap. Aurinko has no meeting recording or transcription product. Horato sends a bot that carries your tenant's brand by default and delivers a post-call transcript and summary, with a live transcript in beta. If meetings are anywhere on your roadmap, this one difference can end the evaluation.
Two smaller gaps are worth knowing before you commit. Aurinko does not publish an uptime SLA or an official first-party SDK list, so plan on direct REST integration and ask the team about availability guarantees. Its scale claims are also more modest than the largest vendor in the category, which may or may not matter for your risk tolerance.
Pricing, in plain terms
Aurinko charges per account per month, tiered by data transfer: $1 under 1GB, $1.50 under 5GB, and $2 for unlimited. BrightSync adds $2 to $4 per user. That entry point is the lowest in the category, and for light mailboxes it stays low at any scale.
Horato starts free with 3 development accounts and no card. Pro is $10 per month with 10 active accounts and 10 shared recording hours included. Additional accounts are $1 each, or $0.75 each above 1,000, and provider connections never raise the billable count. Recording past the pool is $0.70 per hour managed or $0.30 per hour with your own transcription key, and recordings are kept 30 days by default, configurable from 1 to 365.
For light-transfer accounts the two run neck and neck: both work out to about $1 per account per month, and above 1,000 accounts Horato drops to $0.75 while Aurinko stays at its transfer-tiered rates. Heavy mailboxes change it: Aurinko's unlimited tier is $2 per account, while Horato's account price does not vary with data transfer. The honest summary is that neither product will win or lose your deal on account price. The decision is the surrounding surface.
How to choose
Choose Aurinko when CRM sync is on your roadmap, when your users bring Zoho, iCloud, or EWS accounts, or when a pass-through API to the raw provider matters to your architecture. The CRM layer in particular has no equivalent here, and pretending otherwise would waste your time.
Choose Horato when you need meeting recording under your own brand, booking pages on your own domain, signed webhooks with a delivery log you can audit, or agent tools that a human approves before they run. You give up provider breadth past Google and Microsoft, and you gain surfaces Aurinko does not sell at any price.
About these numbers
The Aurinko details above come from its public pages as checked in August 2026, and the Horato side comes from our published pricing on the same date. Packaging changes and tiers move, so this page will lag reality eventually. Verify the current numbers with Aurinko directly before you budget, and rerun the per-account math against your own mailbox sizes.