IS-IS VS SMTP
As of 30 October 2026, SMTP is named by 343 companies and IS-IS by 110; IS-IS skews to companies under 200 people (40% vs 41%), SMTP to companies over 1,000 (36% vs 41%).
As of 30 October 2026 · refreshed daily · counts move as websites, DNS and career sites are re-read.
The website-and-DNS footprint is not comparable between a marketing suite and a CRM: IS-IS's script and mail records show on hundreds of thousands of small sites, SMTP rarely leaves a trace outside its own apps. Compare on the job-posting numbers; use the footprint for reach.
- IS-IS: 2–200 employees
- 40%
- SMTP: 2–200 employees
- 41%
- IS-IS: 1,000+ employees
- 41%
- SMTP: 1,000+ employees
- 36%
- Postings per company, 90 days
- 3.7 · 2.1
- Website or DNS footprint
- 0 · 0
Who chooses which
Share of each tool's companies in every segment. "Leans" marks a gap of more than two points.
| Segment | IS-IS | share | SMTP | share | Leans |
|---|---|---|---|---|---|
| 2-10 employees | 5 | 5% | 15 | 4% | even |
| 11-50 employees | 12 | 11% | 73 | 21% | SMTP |
| 51-200 employees | 27 | 25% | 51 | 15% | IS-IS |
| 201-500 employees | 13 | 12% | 46 | 13% | even |
| 501-1000 employees | 8 | 7% | 33 | 10% | SMTP |
| 1001-5000 employees | 19 | 17% | 65 | 19% | even |
| 5001-10000 employees | 7 | 6% | 24 | 7% | even |
| 10,001+ employees | 19 | 17% | 36 | 10% | IS-IS |
| Segment | IS-IS | share | SMTP | share | Leans |
|---|---|---|---|---|---|
| Technology & software | 56 | 51% | 198 | 58% | SMTP |
| Utilities & infrastructure | 27 | 25% | 11 | 3% | IS-IS |
| Manufacturing & industry | 6 | 5% | 27 | 8% | SMTP |
| Media & content | 6 | 5% | 5 | 1% | IS-IS |
| Business & finance services | 5 | 5% | 60 | 17% | SMTP |
| Public, community & associations | 3 | 3% | 13 | 4% | even |
| Property & construction | 3 | 3% | 3 | 1% | even |
| Automotive | 1 | 1% | – | – | outside top 12 |
| Consumer services & leisure | 1 | 1% | 8 | 2% | even |
| Health care | 1 | 1% | 2 | 1% | even |
| Transport, logistics & rental | 1 | 1% | 3 | 1% | even |
| Commerce & trade | – | – | 10 | 3% | outside top 12 |
| Hospitality & travel | – | – | 2 | 1% | outside top 12 |
| Segment | IS-IS | share | SMTP | share | Leans |
|---|---|---|---|---|---|
| United States | 64 | 58% | 213 | 62% | SMTP |
| United Kingdom | 10 | 9% | 20 | 6% | IS-IS |
| Germany | 7 | 6% | 8 | 2% | IS-IS |
| France | 7 | 6% | 15 | 4% | even |
| Italy | 3 | 3% | 11 | 3% | even |
| Belgium | 2 | 2% | 5 | 1% | even |
| Brazil | 2 | 2% | 3 | 1% | even |
| Switzerland | 2 | 2% | – | – | outside top 12 |
| Czechia | 2 | 2% | – | – | outside top 12 |
| Norway | 2 | 2% | – | – | outside top 12 |
| Australia | 1 | 1% | 4 | 1% | even |
| China | 1 | 1% | – | – | outside top 12 |
| Canada | – | – | 13 | 4% | outside top 12 |
| India | – | – | 11 | 3% | outside top 12 |
| Poland | – | – | 8 | 2% | outside top 12 |
| Singapore | – | – | 4 | 1% | outside top 12 |
| Segment | IS-IS | share | SMTP | share | Leans |
|---|---|---|---|---|---|
| IT operations & business systems | 291 | 55% | 587 | 49% | IS-IS |
| Software engineering | 60 | 11% | 186 | 16% | SMTP |
| Sales | 26 | 5% | 41 | 3% | even |
| Engineering (non-software) | 19 | 4% | 56 | 5% | even |
| Skilled trades and field service | 10 | 2% | 3 | 0% | even |
| Customer service & success | 9 | 2% | 58 | 5% | SMTP |
| Construction and civil | 5 | 1% | – | – | outside top 12 |
| Product, program & project management | 5 | 1% | 11 | 1% | even |
| Manufacturing and production | 4 | 1% | – | – | outside top 12 |
| Facilities cleaning and security | 2 | 0% | – | – | outside top 12 |
| Administration & office | 1 | 0% | – | – | outside top 12 |
| Healthcare support and caregiving | 1 | 0% | – | – | outside top 12 |
| Data & AI | – | – | 25 | 2% | outside top 12 |
| Quality, safety & environment | – | – | 12 | 1% | outside top 12 |
| Marketing & communications | – | – | 5 | 0% | outside top 12 |
| General management & consulting | – | – | 4 | 0% | outside top 12 |
| Logistics warehouse and transport | – | – | 4 | 0% | outside top 12 |
The companies behind each column
Companies using IS-IS →
Companies using SMTP →
network protocols ranked →
Quote the sentence with the date and the link. The numbers change daily; the link always shows the current ones.
SMTP is named by 343 companies in job postings and IS-IS by 110; 0 name both. (Breaknorm, 30 October 2026, https://breaknorm.co/compare/is-is-vs-smtp)
Read from the source, not self-reported
Every number on this page can be traced to a page we crawled or a posting we read. Full methodology →
- Job postingsRead hourly from career sites. A tool counts when the employer's own text names it as the team's system; both tools can count for one company.
- Website and DNSScripts and embeds on the company's pages, plus SPF, DKIM, MX and CNAME records of its domain that point at the vendor.
- SegmentsCountry, size and industry from the company profile built from its website.
- Not a reviewNo ratings, prices or feature claims. For those, read the vendors.
IS-IS vs SMTP: questions
Which is more used, IS-IS or SMTP?
By companies naming it in their own job postings, SMTP (343) over IS-IS (110). By website-and-DNS footprint, SMTP (0 vs 0), because its scripts and mail records sit on many small company sites.
Who chooses IS-IS?
40% of IS-IS companies have 2 to 200 employees, against 41% for SMTP. 41% of IS-IS companies have over 1,000 employees, against 36% for SMTP.
Do companies run both?
0 companies name both in their postings, usually IS-IS in marketing and SMTP in sales, or during a migration.
Where do these numbers come from?
From the employer's own text in job postings read hourly from career sites, and from scripts found on company websites in our crawl. No vendor data, no surveys.
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