---
title: "Custom Request Headers — Lemwatch Help"
description: "Send custom HTTP headers with every check — bearer tokens, User-Agents, host overrides. Validated as JSON, 4 kB cap."
canonical: "https://lemwatch.com/help/custom-request-headers"
source: "https://lemwatch.com"
---

# Custom Request Headers

> Send custom HTTP headers with every check — bearer tokens, User-Agents, host overrides. Validated as JSON, 4 kB cap.

## Custom Request Headers

 Send extra HTTP headers with every check so LemWatch can reach endpoints that need authentication, a specific User-Agent, or a host override.

### Format

 A JSON object — keys are header names, values are strings.

### Rules

- Must be valid JSON parsable as an object (not an array, not a bare string)

- Max 4,000 characters total

- Header names and values are sent verbatim — no escaping applied

- Empty string "" is treated as "no custom headers"

### Common patterns

 **Protect a staging environment**

 **Allowlist past your WAF**

 **Pin a CDN edge**

### Security

 Headers are stored encrypted at rest. They are visible in the audit log to admins of your organization. Rotate any token if a teammate leaves.

### Troubleshooting

- "Custom headers must be a valid JSON object" — your value is missing braces, has a trailing comma, or is an array

- Auth header ignored — confirm the upstream actually accepts the header name (some WAFs strip Authorization )

- Headers gone after save — make sure you're on the latest build; older releases dropped this field due to a Zod schema gap


## Related

- [Help centre](https://lemwatch.com/help)
- [Advanced Monitoring Fields](https://lemwatch.com/help/advanced-monitoring-fields)
- [Custom HTTP Methods & Headers](https://lemwatch.com/help/custom-http-methods)
- [API Endpoint Monitoring](https://lemwatch.com/help/api-endpoint-monitoring)
- [Expected Body Content](https://lemwatch.com/help/expected-body-content)
- [Acknowledging Incidents](https://lemwatch.com/help/acknowledging-incidents)
- [Lemwatch pricing](https://lemwatch.com/pricing)
- [How do I use my own domain for a status page?](https://lemwatch.com/help/custom-status-page-domain)