Every frontend dev and QA engineer knows this dance:
- You need to change one response a live site returns — a script, a CSS file, a JSON payload.
- Someone tells you "just use DevTools Local Overrides."
- You set it up. It works... until you reload your browser profile, need it scoped per URL, or want a teammate to use the same setup.
- You look at the paid tools and discover your options went upmarket or died.
I've watched this category churn for years:
- Resource Override — dead, never survived the MV3 migration
- ModHeader — went freemium, 10-rule cap, ads in your browser
- Requestly — a genuinely good product that got acquired by BrowserStack and moved enterprise ($10–15/user/mo)
- Charles Proxy / Fiddler — full proxies, $50+, overkill for "swap this one file"
And Chrome's own Local Overrides, which shipped in 2018, still has the same rough edges: it disables your cache, it's per-browser-profile, there's no scoping, no sharing, no request-header modification.
So I built the tool I kept wishing existed
WebWarp keeps the live application, the real backend, your real session — and swaps only the response you care about:
- Match a URL, map a local file (JS, CSS, HTML, images, fonts), reload — it's live
- Response rules: block, redirect, mock
- Per-file URL scope, query and cookie conditions
- Live reload and auto-reapply
- Injection profiles, team sharing, DevTools panel
- Companion extension for Chrome, Edge, and Firefox
No proxy configuration. No deployment queue. No re-setup every session.
Honest comparison
| Capability | DevTools Local Overrides | Requestly | WebWarp |
|---|---|---|---|
| Price | Free | $10–15/user/mo | $19–38/mo |
| Override response bodies | Yes | Yes | Yes |
| Modify request headers | No | Yes | Via rules |
| Scoped rules (URL + query + cookie) | No | Yes | Yes |
| Team sharing | No | Yes | Yes |
| Browsers | Chrome/Edge | Chrome, Edge, Firefox | Chrome, Edge, Firefox |
| Cache impact | Disables cache | None | None |
My honest recommendation: if you mock one endpoint occasionally and live in Chrome, use DevTools Local Overrides. It's free. Don't pay anyone — including me — for that.
If you're a team that needs shared rule sets, scoped conditions, and cross-browser coverage, and you're already paying for Requestly, it's a fine product.
If you want the team-grade workflow without the per-user subscription line item — that's the slot WebWarp was built for.
Founder launch
I'm doing a founder lifetime deal for the first 100 seats: $99 once, everything in Pro, forever. When 100 are gone, the deal ends — no extensions. There's also a 14-day free trial on the monthly plans (card required, charged on day 15).
Founder and annual plans charge today, so this is also me being upfront: I'd rather earn revenue now from people who want the tool than wait out a trial cycle.
I'm the founder and I'll be in the comments. Ask me anything — especially the ugly questions about MV3 response-body limits, what happens if I go out of business (the extension keeps working with local rules), and why the seat counter is real.
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