The open-source browser
DevTools you're missing

Modify HTTP traffic, record browser sessions, team collaboration

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open-source · Code signed · Fully offline · MIT license · Read the docs
openheaders://app · HTTP Rules
OpenHeaders — HTTP Modification Rules
capabilities

Everything you need to
own the network layer

Built for developers who need deep visibility and control over browser HTTP traffic — without sending a single byte to the cloud.

core feature

Intercept & Modify HTTP Traffic

Add, remove, or override request and response headers in real time. Inject values from environment files, local HTTP endpoints, or regex-matched patterns.

  • Modify headers, payloads & query params
  • Block or redirect requests by URL pattern
  • Inject scripts & CSS into any page
  • Dynamic values from env / file / HTTP sources
  • Regex-based URL matching
HTTP Modification Rules
session recording

Record & Replay Complete Sessions

Capture every network request, console log, DOM event, and storage change — timestamped, seekable, and fully reproducible.

  • One-click recording from the extension
  • Full timeline scrubbing & playback controls
  • Console, Network, Storage & Info tabs
  • Skip-inactive mode for long sessions
Session Playback
record

Capture Workflows

Attach recordings to bug reports, create onboarding demos, or document reproduction steps — all with full technical context preserved.

  • 🔧Console
  • 🌐Network
  • 💾Storage
  • 🖱️Mouse events
  • 📊Page metrics
Record Workflow
export

Export in Any Format

MP4 or WebM video for sharing. JSON for perfect programmatic reproduction — import back into OpenHeaders for instant replay.

Export Options
collaboration

Team Workspaces via Git

Sync rule sets and environments across your team using any Git repository. Sensitive values stay locally encrypted — only the structure travels.

  • Git-based config synchronization
  • Branch-based workflow support
  • Invite teammates via shareable join links
  • Sensitive data stays locally encrypted
Team Workspaces

Zero Telemetry

No analytics, no crash reporting, no usage metrics. What you do stays on your machine, full stop.

Fully Open Source

MIT licensed and fully transparent. Audit every line, fork it, extend it, or embed it in your own toolchain.

Pro-Grade Docs

Comprehensive documentation with guides, API reference, and examples.

use cases

Built for the way
developers actually work

Real workflows teams use OpenHeaders for every day.

Developer

Local dev against a staging API

Inject auth tokens and custom headers on every request — no .env edits, no proxy, no server restart.

Authorization→Bearer ${TOKEN} · X-Tenant-ID→staging-42
Header injection Env file values
QA Engineer

Jira bug reports with session replay

Record the exact reproduction steps and attach the exported JSON to the ticket. Dev imports it, hits play.

Record → Export JSON → Attach to Jira → Replay
Session recording JSON export
Team Lead

Rule sets synced via Git

Commit header rules to a shared repo. Everyone pulls the latest config — no Slack threads, no stale wikis.

git pull→rules in sync · invite link→teammate joins
Git sync Team workspaces
Developer

Simulating failures without a mock backend

Block an endpoint and inject a custom error response. Test retry logic and error UI in seconds.

POST /charge→503 blocked
Request blocking Response override
Security Engineer

Auditing security header degradation

Strip CSP or HSTS from responses in-browser and observe how your app behaves — no flags, no proxy.

Strict-Transport-Security→stripped
Response headers Zero telemetry
DevRel / Product

Onboarding demos with real network context

Record a product walkthrough with live network and console data. Export as MP4 or shareable JSON.

Record → MP4 share · JSON → step-through replay
Session recording MP4 / JSON export
why openheaders

One tool.
No subscriptions. No cloud.

OpenHeaders Free Requestly Postman
Price / user / year $0 $276 $228
Privacy & Ownership
Open source MIT licensed
Fully offline Cloud-based Cloud-based
Telemetry Zero telemetry Collected Collected
No account needed
Traffic Control
Header modification Limited
Request blocking & redirect
Session recording & replay Full fidelity replay Paid only
Workspace
Team Workspace Sync Via Git Cloud only Cloud only
Workspaces & environments Personal & Team Cloud only Cloud only
API requests
pricing

Free & open source. No catches.

Open source — MIT license
$ 0

everything included

  • Unlimited modification rules
  • Unlimited HTTP / Env / File sources
  • Unlimited session recordings
  • Team workspace collaboration
  • Personal and commercial use
  • Community support (chat & email)
  • No telemetry or data collection
enterprise / custom

Need something more?

We're continuously improving OpenHeaders based on real developer feedback. Custom features, priority support, or a private deployment — reach out.

Start a discussion
get started

Download OpenHeaders

desktop application

Desktop App

macOS, Windows, and Linux. Code signed on macOS and Windows.

Download Desktop App Detecting platform…
All platforms & architectures
browser extension

Browser Extension

Works alongside the desktop app to intercept and modify traffic in your browser.

Chrome ↗ Microsoft Edge ↗ Firefox ↗