Generate valid Content-Type headers with charset and boundary
Quick CTA
Fill type and subtype first to generate a Content-Type header; boundary, extra params, and scenario comparisons stay in Deep.
Deep expands pitfalls, recipes, snippets, FAQ, and related tools when you need troubleshooting or deeper follow-through.
Content-Type Generator builds copy-ready HTTP Content-Type values for API requests and responses. Choose media type and subtype, then add optional charset, boundary, and custom parameters to generate normalized output immediately. It is useful for Postman and cURL testing, backend integration, gateway policy checks, and API documentation. The tool helps prevent common mistakes such as missing charset, incorrect multipart boundary, or malformed parameter syntax. You can copy pure Content-Type values or full header lines directly. All generation runs in your browser.
Value only
Use it in GUI clients or config fields that already label the header key.
Full header line
Use it in docs, raw HTTP examples, or tools that expect a complete header block.
Note: Choosing the right output format prevents copy/paste mistakes during handoff.
application/json
Use it for regular successful business payloads.
application/problem+json
Use it for standardized error envelopes that follow RFC problem details.
Note: Keeping success and error media types explicit makes client behavior more predictable.
Generic default
Use for internal prototypes and quick mocks.
Endpoint-specific
Use for stable APIs and interoperable client contracts.
Note: Specific content types reduce interpretation ambiguity across clients.
Manual drafting
Use for one-off debugging commands.
Generated templates
Use for docs, SDK examples, and onboarding assets.
Note: Templates improve consistency across teams and environments.
Fast pass
Use for low-impact exploration and quick local checks.
Controlled workflow
Use for production delivery, audit trails, or cross-team handoff.
Note: Content Type Generator is more reliable when acceptance criteria are explicit before release.
Direct execution
Use for disposable experiments and temporary diagnostics.
Stage + verify
Use when outputs will be reused by downstream systems.
Note: Staged validation reduces silent compatibility regressions.
Bad input: `multipart/form-data` header emitted with missing boundary.
Failure: Server cannot parse form payload and returns 400.
Fix: Generate multipart headers with auto-managed boundary tokens.
Bad input: Responses always set `application/octet-stream`.
Failure: Browser behavior and downstream tooling lose type-specific handling.
Fix: Map concrete media types whenever file type is known.
Bad input: Consumer-side constraints are undocumented.
Failure: Output appears valid locally but fails during downstream consumption.
Fix: Normalize contracts and enforce preflight checks before export.
Bad input: Fallback behavior diverges between staging and production.
Failure: Same source data yields inconsistent outcomes across environments.
Fix: Declare compatibility constraints and verify with an independent consumer.
Q01
Add charset when you serve text payloads that must render predictably, such as JSON, HTML, XML, CSV, or plain text.
Q02
Use a boundary for multipart/form-data requests, especially file uploads, and make sure it matches the body separators exactly.
Recommend: Use simple defaults to keep iteration fast.
Avoid: Avoid overfitting full production header policy too early.
Recommend: Use endpoint-specific generated templates with contract tests.
Avoid: Avoid vague fallback types in official examples.
Recommend: Use fast pass with lightweight verification.
Avoid: Avoid promoting exploratory output directly to production artifacts.
Recommend: Use staged workflow with explicit validation records.
Avoid: Avoid one-step execution without replayable evidence.
Cause: The boundary token must match the current request body, not an old sample from another tool or environment.
Fix: Generate a fresh header value for the exact request you are about to send.
Cause: Some tools expect only the Content-Type value, while others expect the full `Content-Type:` header line.
Fix: Decide which format the destination needs, then copy the matching output variant.
Cause: Some teams reuse upload templates and accidentally ship incorrect media types for normal JSON requests.
Fix: Define request templates per endpoint type and enforce Content-Type checks in integration tests.
Goal: Create a valid multipart/form-data value that can be copied into Postman, curl, or gateway configs.
Result: You avoid malformed upload headers and reduce trial-and-error during integration debugging.
Goal: Generate consistent `application/problem+json; charset=utf-8` headers across services.
Result: Clients receive predictable error payload typing, improving observability and SDK handling.
Goal: Validate assumptions before output enters shared workflows.
Result: Delivery quality improves with less rollback and rework.
Goal: Convert recurring failures into repeatable diagnostics.
Result: Recovery time drops and operational variance shrinks.
HTTP
Content-Type: multipart/form-data; boundary=----WebKitFormBoundary7MA4YWxkTrZu0gWAPI Debugging Checklist: From Broken Response to Root Cause
A practical debugging flow for API payload errors, auth failures, and malformed responses.
Why 415 Unsupported Media Type Happens (and How to Fix It Fast)
A practical problem page for debugging 415 errors with exact header checks and copy-ready fixes.
Content-Type Generator (MIME Header Builder) is most reliable with real inputs and scenario-driven decisions, especially around "Quick local prototyping".
You can generate common and custom Content-Type values, including application/json, text/html, application/xml, and multipart/form-data.
Yes. The generator supports charset, boundary, and additional custom parameters in one header value.
When uploading files with multipart/form-data. The boundary must match the request body separators.
Yes. You can copy generated Content-Type values directly into Postman headers or cURL commands.
Correct charset prevents encoding issues and garbled text, especially for multilingual content.
No. Header generation is fully client-side in your browser.