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Follow along with the demo captures

The examples in this guide run on three HAR files that you can download. They are enough to try every command and get exactly the output shown, without capturing anything yourself.

The captures are synthetic

They were generated by scripts/docs-make-demo-hars.py, not recorded from a real service. The shop is called shop.example, a name reserved so that it can never be a real site. The addresses come from ranges reserved for documentation, and every token and key is a made-up string. The output you see is real WireTrail output on these files, and each file says that it is synthetic in its log.comment field.

Download them

You need WireTrail on your PATH first. See Download and install.

curl -fsSLO https://wiretrail.neerdael.nl/assets/downloads/checkout.har
curl -fsSLO https://wiretrail.neerdael.nl/assets/downloads/baseline.har
curl -fsSLO https://wiretrail.neerdael.nl/assets/downloads/sanitized.har

If you cloned the repository, they are in docs/user-guide/assets/downloads/.

File What it is Entries
checkout.har A 70-second session of a web shop: load the page, sign in again, browse, search, check out. It holds the problems this guide teaches you to find. 99
baseline.har The same session from an earlier build with most of those problems removed. It still has a 502 that succeeds on a retry, one failed banner request and some repeated calls, so summary exits 1 on it, but diagnose and auto find nothing and exit 0. Compare and the CI gate use it as the known-good capture. 53
sanitized.har checkout.har as an exporter that strips credentials and bodies would write it. Validate uses it. 99 
for f in checkout baseline sanitized; do printf '%s.har: ' $f; wiretrail $f.har export | wc -l | tr -d ' '; done

checkout.har: 99
baseline.har: 53
sanitized.har: 99

A first look at what the main capture contains:

wiretrail checkout.har validate

HAR 1.2 via WireTrail demo generator (synthetic)  (99 entries)
with timings: 99% · response bodies: 81% · POST req bodies: 100%
auth headers: true · cookies: true

anomalies:
  status-0: 1

What is planted in checkout.har

This is the answer key. Each row says what to look for, which entries show it, and where to read about the command that finds it. Entry ids are the same in every command.

What happened Entries Find it with
The page loads through a redirect from www to the bare host e000000 Redirects
The same image URL is redirected six times, once per view e000007, e000020, e000039, e000053, e000067, e000074 Redirects
The app starts with an expired token and gets 401 three times e000011 to e000013 Auth failures and refresh, JWTs
A token refresh succeeds, but a call sent just after it still carries the old token e000014, e000015 Debug a token refresh race
Product list pages are requested, and page 3 twice e000022 to e000025 Pagination and N+1
One request per product to fetch a price: twelve in a burst e000026 to e000037 Spot an N+1, Storms
A heartbeat call repeats every 1.5 seconds with only a timestamp changing e000038, e000041, ... Remove redundant calls, What varies between calls
A stock call fails with 502 and succeeds on the second try e000054 to e000056 Retries
An image request fails before any status arrives, then succeeds e000059, e000064 Errors, Validate a capture
A cart sync is tried five times (four retries) and never recovers e000069 to e000076 Retries, Your first triage
A search endpoint answers 429 with Retry-After, and the app keeps calling e000077 to e000081 Rate limits
A payment is declined, and the first attempt has no idempotency key e000087, e000088 Rules and rule packs
One call waits 2.4 seconds on the server e000090 Slowest calls, Why a call is slow
Calls that lose their time to DNS, connecting, queueing, uploading and downloading e000086, e000021, e000032, e000092, e000009 Slowest calls, Timing phases
Bodies and content types that do not match e000091, e000093 to e000096 Built-in checks
A download link with a token and a signature in its query string e000098 How redaction works

The small files for the limitations

Limitations shows behaviors that a reader might not expect. Each has a tiny capture of its own, in assets/downloads/quirks/, so you can run the command and see it yourself. The page names the file next to each claim.

Set up a work folder

Every command in this guide runs in a folder that holds the three files:

mkdir wiretrail-demo && cd wiretrail-demo
# download the three files here, then:
wiretrail checkout.har