Preview the copy
How it works
Parse
The copy is walked character by character. {{name}} and {name} become variables, {a|b} becomes a spin block, and nesting is tracked.
Validate
Unclosed or stray braces, empty alternatives, single-option spins, duplicate alternatives and mixed variable syntax are all reported with position.
Count
Distinct variants are the product of every block's alternatives, recursively. Word count is given as a shortest-to-longest range.
Render
Random variants are rendered with your sample values. Variables without a value are marked so you can see where the copy would break.
Why spintax is worth the trouble
Twenty inboxes sending the same three sentences produce a pattern that Gmail's filters can fingerprint within a day. Spintax breaks the pattern: a handful of alternatives in the greeting, the opener and the ask multiplies into hundreds of distinct messages that say the same thing. It is not a substitute for warmed domains or a clean list, but it is the difference between a sequence that runs for six weeks and one that runs for six days. The number that matters is distinct variants against daily volume — under a few dozen and the repetition is still visible.
What breaks in practice
A missing pipe turns a spin into a literal brace in the prospect's inbox. A missing close brace swallows the rest of the message. A variable typed as {{firstname}} when the tool expects {{firstName}} is sent as-is. Mixing {{var}} and {var} syntax because two people edited the template means one of them leaks. All of these pass a visual read and all of them are caught here, because the parser does what the sending tool does rather than what you meant.
Variables and fallbacks
The sample values box exists because the render is only useful with realistic data. Put in the longest company name on your list, not the shortest, and read the result — "Saw International Business Machines Corporation is hiring" is a real thing I have watched go out. Most tools support fallbacks ({{firstName|there}} in Instantly); this tool leaves those to the tool and simply marks variables that have no sample value so you can see where a fallback is needed.
How many variants is enough
Enough that no single version is sent more than a couple of times a day per inbox. Five inboxes at twenty-five sends a day is 125 messages; 48 variants means each goes out under three times, which is fine. The same fleet with a template that has three variants is sending each one forty times a day, and the spins might as well not be there. The download button gives you every variant when the count is small enough, which is the quickest way to proofread the ones you did not think about.
Frequently asked questions
What is spintax?
A syntax for alternatives inside text: {Hi|Hey|Hello} renders as one of the three at send time. Blocks can be nested. Every major cold email tool supports it.
Which variable syntax does my tool use?
Instantly, Lemlist, Apollo and most others use {{firstName}}. Smartlead and Woodpecker use {firstName}. Set the dropdown if auto-detect gets it wrong, and never mix the two in one template.
How is the variant count calculated?
Each spin block contributes its number of alternatives; nested blocks multiply within their parent. The total is the product across all top-level blocks. Variables do not add variants.
Does the tool support fallbacks like {{firstName|there}}?
It treats that as a variable named firstName|there and marks it. Fallback handling is tool-specific, so test it in the tool. The purpose here is to catch structural mistakes, not to emulate every sender.
Does spintax stop emails going to spam?
It reduces one signal: identical copy across many sends. It does nothing for authentication, warmup, volume or list quality. Use it alongside those, not instead of them.
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