Real numbers are the most compelling thing a builder can post. "First paying customer, $4.99" beats any amount of description, because it is specific, verifiable in principle, and unmistakably real.
They are also the hardest content to undo. Worth thinking about before rather than after.
What posting a number actually does
It sets a baseline. Post $400 MRR and every subsequent post is read against it. Six months later, $600 reads as slow. The number you posted at the start defines the story you are telling from then on, whether or not you wanted that story.
It changes who arrives. Revenue posts attract people interested in revenue. Some of them are peers. Some of them are selling growth services. A few of them are unpleasant. This is a different audience from one attracted by the problem you solve.
It cannot be retracted. Screenshots are archived, quoted and screenshotted again. There is no editing it later.
It invites the follow up. Post a number once and people ask for the next one. Not posting it becomes a signal in itself.
None of this means do not. It means decide deliberately, because the default path is that a screenshot does well once and you are now a revenue-posting account.
Numbers with less baggage
Several kinds carry most of the credibility with fewer consequences:
Time. "Built in four days." Concrete, verifiable, no ongoing obligation.
Scope. "Three tables, one scheduled function, 900 lines." Extremely specific and tells the reader nothing commercially sensitive.
Firsts rather than totals. "First paying customer" is a milestone. "$4,200 MRR" is a running score. The first is a moment, the second is a commitment to reporting.
Performance. "Cut it from 4 seconds to 400 milliseconds." Real and technical and nobody's business commercially.
The general principle: numbers that describe a moment age well, numbers that describe a position demand updates.
If you do post revenue
Some things that help:
Post the first, not the level. "First payment came in" rather than "currently at $X".
Include the shape. A number with no context invites the reader to invent one. "$400 from 12 customers" says something different from "$400 from one enterprise pilot".
Do not round up. $4.99 is more credible than "nearly five dollars", and precision is most of why these posts work at all.
Decide the cadence in advance. Monthly, quarterly, or never again. Deciding in the moment means deciding when the number is good, which is how people end up with a public record of only their best months.
The rule we built in
Noomachy DevTracker blocks any number in a generated post that does not appear in the source material. 40% faster fails if no 40 appears in the commits. It is the single most effective check in the product.
That creates an obvious problem: it also blocks the genuinely good numbers, because "first paying customer, $4.99" is not in your git history.
The answer is that milestones are things a person types. A label, a value, a date. Once you have entered it, it becomes evidence and the validator accepts numbers drawn from it.
The distinction is the entire point. The tool never infers that you got a customer. You tell it you did, and then it can write about it. Which happens to be exactly the right division of responsibility for any number going out under your name.