Spintax rotates word choices so each message differs slightly. It was designed for an era when filters fingerprinted message bodies and blocked identical copies. Modern providers weight sending behaviour far more heavily than body text, so spintax addresses a threat that is mostly gone while adding a real risk of awkward copy.
Published by emailcampaign.ai. Our product supports spintax because customers ask for it. This page argues you probably should not lean on it, which is worth weighing against the fact that we built the feature.
What spintax is
A template containing alternatives, one of which is chosen per send:
{Hi|Hello|Hey} {{firstName}}, {quick|short} question about {{company}}.
That renders as "Hi Sarah, quick question about Acme" or "Hey Sarah, short question about Acme", and so on. An empty final option makes a word optional: {really|} includes "really" about half the time.
Syntax is broadly consistent across tools, but nesting support is not. Preview several renderings before any campaign, because a malformed nest produces visible braces in a real message and the template looks fine.
The threat model it was built for
Early spam filtering leaned on content fingerprinting: hash the body, and if the same body arrives ten thousand times, treat it as bulk. Against that, varying the words worked, because it broke the hash.
That is no longer where the decision is made. The signals that dominate today are about the sender rather than the message:
| Signal | Weight | Does spintax affect it? |
|---|---|---|
| Domain and mailbox sending history | High | No |
| Authentication alignment (SPF, DKIM, DMARC) | High | No |
| Complaint rate | High | No |
| Hard bounce rate | High | No |
| Volume and pacing per mailbox | High | No |
| Recipient engagement | Medium | Indirectly, if variants read worse |
| Body content patterns | Low | Slightly |
Every high-weight row is a property of your infrastructure and your list. A message from a cold, unauthenticated domain lands in spam whether or not its adjectives rotate.
The two real costs
Variants that read slightly wrong. Writers test the template, not the twenty-four renderings it produces. Combinations that are grammatically fine but tonally odd get sent, and cold email lives or dies on sounding like a person wrote it deliberately.
It feels like personalisation. This is the expensive one. A template with six spin points looks worked-on, so the targeting work that actually produces replies gets skipped. Rotating "quick" and "short" is not personalisation; naming something specific to that company is.
Where variation genuinely helps
Not in synonyms, but in structure. Two or three genuinely different messages, written separately with different angles and different opening lines, give you real variation and something worth measuring. Run them as an A/B test on reply rate and keep the winner.
That is more useful than one template with a thousand renderings, because you learn something from it.
If you are going to use it anyway
- Preview at least ten renderings, and read them aloud.
- Keep spin points away from the first line, which carries the most weight with the reader.
- Do not spin anything factual, including your company name, the offer, or numbers.
- Avoid nesting unless you have confirmed your tool handles it and you have previewed the output.
- Never spin the unsubscribe line or your postal address, both of which have compliance obligations attached.
What to do with the time instead
Authentication that resolves rather than merely exists: check the full include tree, because a duplicate SPF record or an eleventh DNS lookup outweighs any copy decision. Then volume discipline at eight to ten sends per mailbox per day, and a first line that could only have been written for that recipient.
Questions, answered straight
- What is spintax?
- Spintax is a syntax for writing several alternative wordings inside one template, usually as curly braces with pipe separated options, so each send picks one at random. {Hi|Hello|Hey} {there|} produces a different greeting per message.
- Does spintax still work for deliverability?
- It addresses a threat model that is largely obsolete. Content-fingerprint filtering, which spintax was designed to defeat, is a small part of how Gmail and Outlook decide placement today. They weight sending behaviour: domain history, authentication alignment, complaint rate and bounce rate. Varying adjectives does not change any of those.
- Can spintax hurt my emails?
- Yes, in two ways. Badly written variants produce messages that read as slightly wrong, which costs replies. And because spintax creates the feeling that personalisation has been handled, it often replaces the targeting work that actually drives responses.
- What is the correct spintax syntax?
- Most tools use {option one|option two|option three}, and an empty final option such as {really|} makes the word optional. Nesting is supported by some tools and not others. Always preview several renderings before sending, because a nested error is invisible in the template.
- What should I do instead of spintax?
- Spend the effort on a first line that could only have been written for that recipient, and on volume discipline: eight to ten sends per mailbox per day, across more mailboxes. Those two change placement and reply rate in a way word rotation does not.
Published 20 September 2026. Updated 20 September 2026. Written by the team that runs the infrastructure; numbers come from the platform's own provisioning and sending, and from the providers' published documentation at the time of writing.