Performance: Implement CDN Cache-Control headers for the API

[DamienSable]

📝 Description

Currently, every time a user's GitHub README loads, GitHub's Camo proxy fetches the SVG from our /api/streak endpoint. Without proper HTTP cache headers, we risk burning through Vercel serverless function invocations and hitting GitHub API rate limits.

🎯 What needs to be done

We need to set explicit Cache-Control headers on our Next.js API response. We should use a stale-while-revalidate (SWR) strategy so that the CDN serves a cached SVG instantly, while fetching the fresh data in the background.

📍 Where to look

• app/api/streak/route.ts (Look at the NextResponse return statement).
• MDN Web Docs: Cache-Control

✅ Acceptance Criteria

• The API response includes a header like: Cache-Control: public, s-maxage=14400, stale-while-revalidate=86400 (Cache for 4 hours, revalidate over 24 hours).
• Ensure that error responses (500s or 404s) do not get cached (or are cached for a very short time, like 60 seconds).

[somyarani2003]

Hi maintainers, I would like to work on this issue. I have understood the requirements regarding Cache-Control headers and SWR strategy in the API response. Please assign this issue to me.

[Subhooo5]

Hey @DamienSable @JhaSourav07 , I'd love to work on this under GSSoC 2026! I went through the issue and the Cache-Control docs — the idea is to set s-maxage=14400 so CDNs serve a cached SVG for 4 hours while stale-while-revalidate=86400 lets it refresh in the background without blocking the user. I'll also make sure error responses (500s/404s) either skip caching or use a very short TTL so bad states don't get stuck in the CDN. Can I please get assigned to this?

[anchallll02]

I would like to work on this under GSSoC 2026. I understand Cache-Control + SWR strategy and will implement proper caching with error handling. Please consider assigning me.”

[JhaSourav07]

@Subhooo5
As you already have a opened PR, i cannot assign this issue to you.

@anchallll02

I am assigning this issue to you.

[anchallll02]

Thanks for assigning this issue. I’ll start working on it and raise a PR soon.