Mock/Breakpoint

Mock intercepts requests or responses: **manual Mock** (edit in a full-screen tamper dialog, then continue), or **auto Mock** (apply preset tamper and release; response-only Mock can short-circuit without hitting the origin). Rules are created from the visual capture wizard.

What it does

Use Mock to tweak APIs in joint debugging, simulate errors, or block upstream calls. Each rule has:

• **Match features**: URL, query, body, headers picked from a real request (wildcards supported).
• **Mock mode**: manual Mock (tamper in dialog, then continue) or auto Mock (preset tamper; response Mock can return fake data without contacting the server).

Create from capture

Right-click a row → **Mock**, complete the two-step wizard, and save to the Mock library.

1. **Step 1 · Features**: check URL / query / body / header fields and values used to match later traffic.
2. **Step 2 · Tamper**: pick manual or auto Mock, choose request / response stage, edit headers, body, status, etc.
3. After save, rename, add versions, or toggle enable under **Rules → Mock settings**.

Step 1: pick URL, query, body, or header fields from the current request as match features.

Step 2: choose manual or auto Mock and edit request/response tamper; auto Mock can return a preset response only.

Matching

Matches URL, params, etc. from capture; with param transform, can also match decrypted plaintext.

Multiple rules may be **enabled together**; the list is walked **top to bottom** and **the first hit wins**.

Manual vs auto Mock

Manual Mock

Check request / response (one or both). On hit, the **Mock tamper** dialog opens; edit, then Continue or Abort.

If the rule includes a response stage: after request Continue, wait for the origin response, then edit the response.

Auto Mock

Pick request or response for the **active version** and fill tamper fields. On hit, DevPeek **auto-continues** without a manual Continue click.

**Response-only auto Mock**: returns your configured response **without calling the real server**—handy for 404s, empty lists, error JSON, etc.

Tamper versions

Store multiple presets per rule (e.g. happy path vs error), but **only the active version** runs; switch versions to edit alternates kept on disk.

How tamper applies

Request headers: multi-line `Header: value` format; same-name headers are overwritten. Request/response bodies: tamper text **fully replaces** the original (not appended). Response headers: merged with existing headers; tampered names win. Empty tamper with manual mode still pauses; auto mode with empty tamper usually does not intercept.

Turn rules on

Under Menu › Proxy › Start Mock, tick rules to enable (✓ = on); multiple rules can be active. Also toggle from the capture sidebar Mock panel or Rules › Mock settings.

Recording must be on for new captures to enter Mock; per-client **list pause** skips Mock for that IP.

Mock tamper dialog

Manual Mock opens the full-screen **Mock tamper** dialog; the detail pane stays read-only.

• While pending items exist, the dialog auto-opens and cannot be dismissed via overlay, Esc, or close; it closes when the queue is empty.
• Pending list on the left, header/body editors on the right; footer Continue/Abort for the current item plus Continue all / Abort all.
• Request then response: after request Continue, wait for the response before editing it.
• Title shows pending count; switching queue items syncs list selection and scroll.

After disconnect or Mock wait timeout, the dialog closes with a notice; detail may show a gray reason bar and list rows are muted. See the capture guide for list/detail sync.

Encrypted params: work in plaintext

When param transform rules bind query/body fields, the Mock tamper dialog and rule wizard **auto-decrypt** and default to editable plaintext—you never manually decode or paste ciphertext.

Before manual Continue or auto release, DevPeek **re-encrypts** edited plaintext (requires re-encrypt in conversion config). Mock feature picking and matching also use decrypted plaintext. See Param transform.

Use with param transform

For encrypted params, configure transform first, then use decrypted fields in Mock features. With Map Route, Mock still matches URLs in capture—see the Map Route guide.

Troubleshooting

• Mock never fires: any rule enabled under Proxy → Start Mock? Recording on? Client tab paused?
• No match: features vs live request; encrypted params need param transform first.
• Auto response Mock still hits origin: active version should be response-only with non-empty tamper.

Mock changes what clients see—get approval on shared environments and keep rollback plans.