A developer opens an issue on your repository — a bug, a missing feature, a confusing error — and you work it. You reproduce it, you push a fix, you ship a release. And then, on the closed issue, the reporter leaves a comment that isn't a bug report and isn't a plus-one. It's gratitude with a reason attached: "Confirmed fixed — thank you for the fast turnaround. This was blocking our production deploy and we'd burned two days on workarounds. Really appreciate how you handled it." That's a testimonial, written by the hardest audience you have, in the place they trust most.
Developers are famously resistant to marketing, and that's exactly what makes this kind of endorsement valuable. A comment on a closed GitHub issue was not written for your homepage. It was written by an engineer, mid-workflow, to another engineer, on a platform where nobody performs for a vendor. The credibility is baked in precisely because the setting has nothing to do with selling.
Why a GitHub thank-you outweighs a polished quote
The testimonials most buyers distrust are the ones that sound like marketing — the frictionless superlatives, the "game-changer" with no specifics. A GitHub issue comment is the opposite. It's technical, it's grudging in the good way, and it names the exact thing that hurt: a blocked deploy, a two-day workaround, a migration that finally unstuck. Specifics are what persuade, and issue threads are full of them.
That's the same unprompted, peer-to-peer credibility that makes a Hacker News comment or a Reddit comment recommending your product so persuasive — a real practitioner choosing to say something good where they had nothing to gain. A GitHub thank-you adds one more layer: it's tied to a concrete problem and a concrete resolution that anyone can read in full. The prospect isn't taking a quote on faith; they can scroll up and see the bug, the fix, and the relief in sequence.
Recognize the ones worth keeping
Not every "thanks, closing this" is a testimonial. The ones that convert do three things: they name the stakes ("this was blocking production"), they name the before ("we'd been stuck for a week"), and they credit something specific about you ("the fast turnaround," "the clear explanation," "you understood the edge case immediately"). A bare "works now 👍" is a happy user, not a story — worth noting, not worth quoting.
Watch your own issue tracker, and set up notifications so closed-issue comments don't slip past. When one lands that carries a real before-and-after, capture it while it's fresh: copy the exact text, note the author's handle, and save the permalink to the comment. Issues get edited, repos get archived, and accounts get deleted — a link you saved today is worth more than a screenshot you hope to reconstruct later.
If the thank-you is warm but vague, you have an opening, not a testimonial. A short, genuine reply ("glad it's sorted — out of curiosity, what was this blocking on your end?") often draws out the exact stakes, and now you have the story too. Ask in the thread; developers answer plain questions in plain settings.
Ask permission the platform's way
The comment is public and the repo may even be yours, but public and open-source are not the same as "cleared for our marketing site." Ask anyway — it costs a sentence and it keeps you on the right side of a community that notices when a vendor overreaches.
Reply in the thread or reach out directly, keep it short, and make no assumptions about attribution: "Thanks for the kind words on #482 — glad it unblocked you. Would you be OK with us featuring your comment as a testimonial on our site? Completely fine to decline, and we'd credit it however you prefer — your name, your GitHub handle, your company, or just 'a developer who filed an issue.'" Let them choose. Many developers are happy to be credited with a handle that links back to their profile; others, especially those posting under a work account, will want to check with an employer or stay anonymous. Never attach a company name or a real name they didn't offer — in developer circles that's the kind of thing that gets screenshotted for the wrong reasons.
Most people who took the time to thank you in an issue are glad you asked, and the ones who decline still walk away thinking well of a project that respects the norms of the platform.
Republish it as durable, technical proof
Once you have permission, lift the endorsement onto ground you own, and keep what made it credible. Lead with the sentence that carries the outcome — the unblocked deploy, the recovered days — keep the developer's exact wording, and attach only the attribution they approved. Then place it where a technical buyer will meet it: on the docs page for the feature they were using, on the changelog entry for the fix, or on the landing page aimed at the same engineering team weighing the same decision.
A GitHub comment reads as real because it's terse, specific, and unpolished. Preserve that. Don't smooth "burned two days on workarounds" into "saved us significant time" — the rough, exact detail is the persuasion. If you can, link the published testimonial back to the original issue so a skeptic can verify it in context; a claim a prospect can check for themselves is worth more than one they have to trust. For more sources of the same unprompted, technical endorsement, see how to turn a Hacker News comment into proof that keeps working long after the thread goes quiet.