Overview Leaderboard Methodology
Industry Report

Transactional Email Services

Services focused on sending high-volume, programmatic transactional emails such as receipts, notifications, and password resets with deliverability tools and APIs.

Brands tracked: 36
Brands analyzed: 36
Last updated: 2026-04-23
Model: OpenAI GPT-5
Prompts: 276
Total responses: 1,344
Top Brand Overall?
Postmark
94/100

Highest overall AI Visibility Score in this industry.

LBA Leader?
Mailgun
90

Highest score on the LBA metric in this industry.

Authority Leader?
Postmark
100

Highest score on the Authority metric in this industry.

TOM Leader?
Postmark
100

Highest score on the TOM metric in this industry.

Postmark is the default answer in AI responses for Transactional Email Services

Postmark and Amazon together dominate AI responses for Transactional Email Services. Both brands consistently surface unprompted, with the model treating them as the default answers for most category queries. Brands outside the top two face a structural disadvantage: users are usually given these two before the model even considers alternatives.

Brand Leaderboard All 36 Transactional Email Services brands ranked

Ranked by overall AI Visibility Score (smoothed geometric mean of LBA, Authority, and TOM with an LBA-based floor on Authority and TOM, see methodology). Click any brand for the full report.

# Brand LBA Authority TOM Overall
1
Postmark
postmarkapp.com
 82
100
100
94
2
Amazon
amazon.com
 84
88
93
88
3
SendGrid
sendgrid.com
 82
81
100
87
4
Mailgun
mailgun.com
 90
67
90
82
5
Resend
resend.com
 75
23
37
41
6
Brevo
brevo.com
 75
14
47
37
7
SparkPost
sparkpost.com
 77
9
57
36
8
Mailjet
mailjet.com
 71
7
16
22
9
Microsoft
microsoft.com
 82
8
8
20
10
Mailchimp
mailchimp.com
 79
8
8
19
11
MailerSend
mailersend.com
 63
6
13
19
12
Mailtrap
mailtrap.io
 75
7
7
18
13
WooCommerce
woocommerce.com
 71
7
7
17
14
Elastic Email
elasticemail.com
 66
7
7
16
15
Mandrill
mandrill.com
 66
7
7
16
16
SendPulse
sendpulse.com
 65
7
7
16
17
SMTP.com
smtp.com
 64
6
6
16
18
SMTP2GO
smtp2go.com
 64
6
6
16
19
ZeptoMail
zeptomail.com
 63
6
6
16
20
Google
google.com
 57
7
6
15
21
Netcore
netcorecloud.com
 59
6
6
15
22
Courier
courier.com
 58
6
6
14
23
SocketLabs
socketlabs.com
 53
5
6
14
24
TurboSMTP
turbo-smtp.com
 53
5
5
13
25
GreenArrow
greenarrowemail.com
 46
5
5
12
26
Pepipost
pepipost.com
 45
5
5
12
27
Shopify Tax
shopify.com
 48
5
5
12
28
AuthSMTP
authsmtp.com
 38
4
4
10
29
EmailLabs
emaillabs.io
 32
3
3
9
30
MailPace
mailpace.com
 24
2
2
7
31
DuoCircle
duocircle.com
 19
2
2
5
32
AhaSend
ahasend.com
 7
1
1
2
33
Mailazy
mailazy.com
 7
1
1
2
34
Loops
loops.so
 0
0
0
0
35
Sweego
sweego.io
 0
0
0
0
36
UniOne
unione.io
 0
0
0
0

How is this calculated? Methodology

Every brand in this leaderboard is scored against the same set of 276 shared Transactional Email Services prompts. The same prompts, same model, same iterations. So differences in scores reflect actual differences in AI visibility, not differences in measurement.

Overall AI Visibility Score
Smoothed geometric mean of LBA, Authority and TOM. Authority and TOM are floored at LBA × 0.1 before the geometric mean (the same floor used in the per-metric cards above, so brand cards and the composite tell the same story). Formula: composite = ((LBA + 5)(Authority + 5)(TOM + 5))^(1/3) - 5. The floor keeps brands the model clearly recognises but doesn't yet recommend from collapsing to zero, while a single genuinely weak metric still pulls the composite down. Full methodology.
Shared industry prompts
For Authority and TOM, all brands in the industry are scored against the same 276 category prompts (e.g. "best SEO tools for agencies"). This makes brand-to-brand comparisons valid - everyone faces identical inputs. LBA prompts are per-brand because they ask brand-specific questions.
Latent Brand Association (LBA)
5 brand probes + 1 control prompt, each run 5 times in recall mode (no web search). LBA = quality × meta × stability × share × recognition × 100. Read the full LBA methodology →
LLM Authority
50 organic category prompts (discovery, comparison, problem and transactional intents), each run once in recall mode and once in retrieval mode. Score = frequency × log-decayed prominence × intent weight, then 50/50 averaged across the two modes. Read the full Authority methodology →
Top of Mind (TOM)
15 high-volume discovery prompts (sourced from Keywords Everywhere search-volume data), each run 5 times in pure recall mode (no web). Score = frequency × (0.5 + 0.5 × log-prominence), volume-weighted. Read the full TOM methodology →