HTTP Request Header Builder

📖 Tool Introduction

When you are writing API debugging code, assembling request headers usually means flipping back to MDN to recall the exact spelling of each field: what a realistic User-Agent looks like, what Accept should contain, and which values Accept-Encoding is allowed to carry. This builder collects the ten highest-frequency headers into tickable rows that already come filled with sensible defaults. Tick one to enable it, edit the value on the right-hand input to match your target API, and the dark preview block below instantly reassembles everything into the canonical Name: Value format. Beyond the presets, you can add any number of custom rows for extension headers such as X-Request-Id, and new rows appear in the output immediately. The finished text copies in one click and drops straight into Postman, a curl command or your own fetch calls. Because the whole process runs locally in your browser, even tokens typed into an Authorization field never leave the machine, so the tool is safe to use on laptops that handle internal or production credentials without any risk of leakage to a third party. The output stays in the exact order you ticked the rows, which makes hand-written notes and code reviews much easier to follow than a jumbled dump.

Debugging a flaky API call often comes down to one missing or misspelled header, and typing each one from memory invites exactly those kinds of typos. By starting from a curated list of common headers already filled with realistic defaults, you spend less time recalling spellings and more time focusing on the values your backend actually cares about. The live preview means you can see the assembled request the moment you tick a box, so there is no surprise when the generated list lands in your HTTP client or test script. Everything stays in the tab you are working in; nothing about your selections leaves the page.

✨ Key Features

• Ten common presets: User-Agent, Accept, Accept-Language, Content-Type, Authorization and more
• Editable values: every preset ships with a sensible default that you can tweak inline
• Custom rows: add as many Name: Value pairs as you need, including X- prefixed extension headers
• Live preview: ticking or editing updates the dark output block instantly
• Canonical format: one header per line in strict Name: Value form, ready to paste
• Local and safe: sensitive values such as Authorization are processed only in your browser memory

📝 How to Use

1. Tick the headers you need from the common list; ticked rows become highlighted
2. Click the value field on the right and replace the default with what your target API expects
3. For extension headers, click Add row and fill in a name and a value
4. Check the dark preview block and confirm every line reads Name: Value
5. Click Copy or Download, then paste the result into your debugging tool or code

⚠️ Notes

• Casing convention: header names are case-insensitive, but title-case output matches common practice
• Sensitive data: headers like Authorization and Cookie carry credentials, so redact them before sharing
• No validation: the tool does not check header names or values against any spec; consult your API docs
• Order: header order rarely affects semantics, but output follows tick order for readability
• Fully local: no network request is made; the result comes only from your own choices