SMTP
SMTP scores 56/100 on xpay's Agent-Ready Index v2: partial pricing visibility; self-serve checkout is available; a public API exists with documentation.
SMTP pricing
Essential
$25/mo
flatStarter
$80/mo
flatGrowth
$300/mo
flatBusiness
$500/mo
flatHigh Volume Senders
Contact sales
How SMTP scores on the agent-ready dimensions
Public pricing visibility
15 / 15
Self-serve checkout
15 / 15
Public API + docs
14 / 20
Usage-based / metered pricing
0 / 20
Free entry path
0 / 7
No sales call required
7 / 7
Card / wallet / x402 payment
5 / 6
Machine-readable bonus (MCP / OpenAPI)
0 / 10
Total
56 / 100
What it actually costs at typical scale
50,000 emails per month (Essential plan)
$25/mo
Can an autonomous agent transact here?
Can create account
Can enter payment method
Can upgrade plan
Can buy more usage
Can cancel online
Payment methods
Human approval recommended
Pricing transparency
full
Purchase motion
self_serve
Demo required
Quote required
Annual commit required
Auto-renewal mentioned
Cancellation policy visible
Refund policy visible
Invoice payment available
Purchase orders supported
MSA required
DPA available
Security review required
Trial
Available
API & developer surface
API-first product
Unknown
Public API docs
Sandbox present
Webhooks
MCP mentioned
Positioning & ecosystem
“Affordable SMTP and email relay API services”
Buyer persona
Six-step check: can an agent actually buy from SMTP?
Discover price
Select a plan
Pay per task
Avoid a sales call
API docs without auth
Estimate cost upfront
Pros and cons for AI agents
Observational summary written by xpay from the signals captured on 2026-05-06. Not a review of the product — only of its current pricing posture for agent buyers.- Pricing is publicly visible on an indexable page — agents can read tiers without scraping past auth.
- Every advertised tier is self-serve; no tier requires scheduling a call.
- No per-unit price was advertised, so an agent has no way to estimate the cost of a single task.
- API documentation is gated or absent; an agent cannot inspect the integration surface without authentication.
- PPU requires account creation and an issued API key; a fully unauthenticated agent purchase is not yet supported.
- No /.well-known/ai-pricing.json or equivalent machine-readable pricing manifest is published — agents must rely on HTML scraping.
How SMTP could lift its score
Add a per-unit price (e.g. $X / 1K calls) to the pricing page so an agent can compute its own cost before committing.
| pricing_visible | true |
| headline_phrasing | at $25.0. Offers Custom plan. |
| tier_count | 2 |
| lowest_paid_entry_usd | 25 |
| free_tier | false |
| free_tier_terms | null |
| per_unit_price | null |
| annual_required | false |
| self_serve_paid_tiers | 1 |
| sales_only_tiers | 0 |
| public_api_docs_url | null |
| api_docs_auth_walled | null |
| ai_pricing_json_present | false |
| agents_txt_present | false |
| anonymous_purchase_path | false |
| agent_friendly | {"ai_pricing_json":false,"agents_txt":false,"llms_txt":false,"sitemap_xml":false,"mcp_server_card":false,"agent_skills_index":false,"x402_supported":false} |
Claim this scorecard & lift your score.
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See agent-ready picksSMTP
56
/ 100 (rubric v2.0)Transactional Email
at $25.0. Offers Custom plan.
2
No
$25/mo
1 / 0
Auth-walled
No
Not published
2026-05-09
Tier-based subscription
SMTP pricing starts at $25/mo for the Essential plan; paid plans up to $500/mo. Billed monthly.
Essential plan ($25)
Discovery files and protocols
Side-channel signals — informational, not part of the score. Each protocol is independent; adoption signals the publisher is thinking about agent buyers.ai-pricing.json
agents.txt
llms.txt
sitemap.xml
MCP Server Card
Agent Skills
x402 / MPP
Compare SMTP with peers
Highest-scoring companies in the same category that an AI agent might evaluate as an alternative.Mailgun
87
Amazon SES
85
Mailchimp Transactional Email
85
Postmark
82
UniOne
77
AhaSend
77
Zoho ZeptoMail
73
Aritic Mail
73
Explore the Agent-Ready SaaS Index
25,480+ SaaS scored on agent-buyability — browse by readiness band, category, or jump straight to a pay-per-run tool on xpay.tools.