Free advertising for developer tools, SaaS side projects and apps

You shipped a CLI, an API, a small SaaS, a VS Code extension, an app. It is good. And the traffic graph is a flat line with a spike on the day you posted it somewhere.

Developer audiences are unusually hard to buy: a large share run ad blockers, most ignore anything that reads like marketing, and buying keywords in the dev tooling space is expensive because well-funded companies bid on them. Free channels are not a fallback here — they are the main road.

Make the docs the marketing

For technical products, documentation is the highest-converting page you will ever write. Developers evaluate by reading the quickstart, not the landing page. Two things pay off immediately:

• A quickstart that works end to end in under five minutes, copy-paste-able.
• Task pages named the way people search: "how to X in Y", error messages verbatim, migration guides from the tool they already use.

Error-message pages in particular are free search traffic nobody competes for: paste the exact error, explain the cause, show the fix.

Launch, but plan for the day after

Hacker News, Product Hunt, relevant subreddits and Lobsters can all send a burst. Treat the burst as feedback, not distribution — the traffic is gone in 48 hours. What matters is what you set up before the spike: a working demo, an email capture, and a repeatable channel that keeps trickling after the front page moves on.

Open source as a distribution channel

Extracting a genuinely useful piece of your product as a small open-source library gives you a GitHub presence, README real estate, and a reason for other developers to link to you. It only works if the library is useful on its own — a crippled teaser gets ignored.

Trade ad space with other dev sites

Here is the asymmetry worth exploiting: there are thousands of small developer blogs, docs sites, tool pages and side projects with modest traffic and no advertising at all. Individually, none of them can sell that space for real money. Collectively, they are exactly the audience you want.

An ad exchange turns that into a channel. You add one line of code to your project's site or docs, a single small closable card appears at the bottom of the page, and in return your ad shows on other tech sites — other people's tools, blogs and apps, browsed by people who install things for a living.

Why it fits dev sites specifically

• Your visitors are the same people you are trying to reach. A dev tool ad on a dev blog is not an interruption, it is a recommendation.
• Docs and blog pages have long sessions, so a bottom card is seen without being intrusive.
• It is a script tag. You already know exactly what you are adding and how to remove it.

Writing an ad developers do not ignore

• Say what it is in the headline, literally: "Type-safe API mocks for Vitest" beats "Ship faster".
• Name the stack. Framework and language names do the targeting work for you.
• No superlatives, no "revolutionary", no exclamation marks.
• Link straight to the docs or a live demo, not a signup wall.

A realistic free stack for a dev tool

1. Quickstart docs that work, plus task and error pages for search.
2. One launch post where your users already hang out.
3. A small open-source piece that earns links.
4. An ad exchange running quietly on your docs and blog, sending a steady trickle of developers.

swapad.net is a free ad exchange for small sites: you add one line of code, show one small closable ad at the bottom of your pages, and your own ad runs on other sites in the same topic.