Find the outcome you need.
Start with a symptom, a platform or the thing you want working.
With JavaScript, search filters the whole collection in your browser. Without it, use the linked pages and section navigation below; query filters need JavaScript.
Showing entries 841–880 of 1179 in this first collection.
Platform
Playwright: test the flows that matter in a real browser, and only what you control
What a browser smoke suite is for, which failure patterns come from timing, shared data and the CI environment, and which guide or paid outcome fits each.
Platform
Sentry: see production errors with readable traces, safe payloads and one alert you can trust
What an error tracker needs before it is useful: readable stack traces, release and environment, filtered sensitive data and a quiet alert, with the guide that covers each and the paid setup job.
Platform
pytest: fixtures, patching and markers, and where test suites quietly go wrong
How pytest's fixture scopes, monkeypatch, temporary directories and skip or xfail markers shape test reliability, with the guide for each pattern and the bounded jobs that fit.
Troubleshooting guide
What a useful written pull request review contains, and what it cannot tell you
Set the standard for a written review of a pull request: what to look at, how to write a finding someone can verify and why a review informs a merge decision without making it.
Troubleshooting guide
Your setup instructions have never been run on a clean machine: test the README before you hand it over
Find the hidden prerequisites in a README by following it, and only it, on a clean environment, and know who should try it and what to record.
Troubleshooting guide
Scanning one page is not an accessibility audit: how to scope an audit of a single flow
Separate what automated accessibility checks find from what needs a person, scope an audit by complete process rather than by page, and know which WCAG 2.2 criteria are new.
Troubleshooting guide
A pytest test passes alone but fails in the full run: look for shared state first
Find what one test leaves behind for the next one, from wide fixture scopes to shared files and environment changes, and prove the cause by changing the order instead of guessing.
Troubleshooting guide
A test fails only at certain times or on some machines: find the clock, the randomness or the environment
Trace a test that depends on the date, a random value or the machine it runs on, and control that input instead of waiting for the next failure.
Troubleshooting guide
Before you skip or mark a flaky test, know what the marker hides
Compare skip, xfail, strict xfail and a separate quarantine suite so that taking a flaky test out of the way leaves a visible, dated record instead of a permanent blind spot.
Free tool
Backlog cost and break-even calculator: arithmetic on your own backlog numbers
Enter your backlog by size, your own hours, review hours, hourly cost, lead time, pace and a monthly running cost to compare, and see total hours, total cost, months to clear and break-even. Not a quote.
Free tool
GitHub Actions failure triage: an ordered checklist of what to check first
Answer eight questions about a failing GitHub Actions run and get an ordered checklist from fixed, documented rules, with the reason, the evidence to collect and the limits of each step. It does not read your logs or diagnose the failure.
Free tool
CSV header diff: find missing, added, renamed and duplicate columns between two files
Paste two CSV header rows, or read the header of two small files in your browser, and see missing, added and likely renamed columns, duplicate and empty headers and the delimiter. Nothing is uploaded.
Free tool
Invoice rounding bench: compare per-line and total rounding, half-up and half-even
Enter invoice lines and see net, tax and gross under four rounding rules side by side, in exact whole-number minor units, with the difference between summing lines and rounding the total. Not tax or accounting advice.
Free tool
Certificate expiry countdown: sort your HTTPS certificates by time left
Paste hostnames and certificate not-after dates. See them sorted by time remaining, flagged at 7, 30 and 60 days, with a renewal-by date for each. Nothing is looked up.
Free tool
DNS cutover TTL planner: when to lower the TTL, switch and raise it again
Enter the current TTL, your planned switch time, the TTL to lower to and when you can lower it. Get exact timestamps and the worst-case time old answers can linger.
Free tool
SPF, DKIM and DMARC record checker: read your pasted records against the RFCs
Paste your SPF, DMARC and optional DKIM key records as text and get specific findings, each with the RFC section behind it. No DNS lookups; nothing leaves your browser.
Free tool
Pack and case unit-price calculator: compare supplier prices per single unit
Enter supplier price lines priced per unit, pack or case. Get the exact price per single unit, the working, and the lines whose pack basis is unclear. No floating point.
Buyer collection
For an engineering lead: turn 'we are behind on versions' into a ranked, dated plan
Name the forcing event, decide who accepts each step, and choose the smallest paid job that answers the question: a plan, one upgrade, a programme or a standing service.
Buyer collection
For an owner whose app nobody maintains: ask for a checkable result, not a version number
Turn a host's retirement notice into a plain request: which part is affected, what 'working' means, who can release it and what you need to send.
Collection
Which upgrade first? A diagnosis order for runtime, framework, build tool and database
An ordered map from the first warning to the right paid job: forcing date, test baseline, inventory, runtime, framework, front-end tooling, data and host, and keeping it supported.
Collection
Moving an app or database to another host or engine: the order that avoids lost writes
An ordered map from the dependency inventory to a rehearsed copy, reconciliation, a write freeze, the switch and a way back, for Heroku moves and MySQL to PostgreSQL moves.
Inspectable example
Synthetic upgrade register: one invented Node.js app, five components and a ranked path
An invented inventory shows how support dates, a test baseline and prerequisites turn into an ordered upgrade path, including a component whose date is unknown and one that is outside our fixed jobs.
Inspectable example
Synthetic MySQL to PostgreSQL reconciliation: counts, checksums, sequences and one failing lookup
An invented rehearsal result shows what per-table evidence looks like, including a zero-date column, a generated-key check and a case-sensitivity failure that must be decided, not hidden.
Inspectable example
Synthetic Express 4 to 5 URL table: patterns, async errors, dotfiles and a removed method
An invented before-and-after table shows how to check that converted route patterns still match the right URLs, with each expected Express 5 result taken from the migration guide.
Troubleshooting guide
MySQL to PostgreSQL: the decisions a data copy does not make for you
Case-insensitive lookups, zero dates, tiny-integer flags, enums, auto-increment keys and views: what the documentation says changes, and which choices belong to you.
Troubleshooting guide
Webpack to Vite: translate the config item by item and treat environment variables as public
Inventory every loader, plugin and setting first, then handle environment variables, require calls and glob imports, and keep the type check that Vite does not run.
Troubleshooting guide
Adopt TypeScript one folder at a time: allowJs, checkJs and a strict area that only grows
How JavaScript and TypeScript coexist, how to find type errors before renaming files, and why strictness is a dial you raise folder by folder.
Troubleshooting guide
Replacing one jQuery or AngularJS feature: write its contract before you touch it
Where support stands for old jQuery and AngularJS, what a feature's hidden contract contains, and how to prove a replacement matches it without rewriting the page.
Troubleshooting guide
Which Node.js line should you move to? Read the project's schedule, then ask your host
Two clocks decide when a Node.js version stops being usable: the project's release schedule and your host's runtime list. How to read both and find every place the version is set.
Troubleshooting guide
Native modules after a Node.js runtime change: what breaks, how to find it and what fixes it
Compiled Node.js add-ons depend on interfaces that stay stable across majors only if they use Node-API. How to find them, test them in a clean install and decide each one.
Troubleshooting guide
Express 4 to 5: test the behaviour changes, not just the methods you rename
The documented Express 5 changes that alter what a route matches, how async errors flow and what request properties contain, with a safe way to check them before upgrading.
Troubleshooting guide
Python 3.9 or 3.10 to 3.13: what was removed, and why compiled packages may not install
The standard-library modules removed in Python 3.12 and 3.13, how to find them in your code and dependencies, and how wheel tags and pinned requirements decide whether an install works.
Troubleshooting guide
Moving off Heroku: list the Procfile, release command, config names, add-ons and jobs first
What a Heroku app depends on outside its repository, how each item behaves according to Heroku's documentation, and how to list them without exposing a single secret.
Troubleshooting guide
Copying a Heroku Postgres database out: capture, download, rehearse the restore and reconcile
How Heroku's logical backups work, why a restore deletes the target first, the snags the documentation names, and what to compare before a final copy.
Troubleshooting guide
Upgrading Rails 7.x: take each minor version separately and read what changes
Why the Rails guide asks for one minor version at a time, what the guide lists for each 7.x step, and how framework-defaults files let you adopt changes gradually.
Troubleshooting guide
A Rails 6 app stuck before 7.0: run the Zeitwerk check and read what it reports
Zeitwerk autoloading is mandatory from Rails 7.0. How to check an app's file and constant names, what typical failures mean, and why eager loading is the real test.
Troubleshooting guide
Webpacker is retired: your Rails JavaScript options and what each means for an upgrade
What 'retired' means for a Rails app, the three successors its README names, and how to inventory what Webpacker does for you before choosing.
Troubleshooting guide
Changing a column on a large table: add, backfill, reconcile, switch, and only then drop
Why a single ALTER can lock or rewrite a big table, what the PostgreSQL and MySQL documentation say about each form, and how a stepwise change keeps a way back.
Troubleshooting guide
Reading vendor support dates: upstream, host, scheduled and final are different things
How Node.js, Python, Rails, Ruby, PostgreSQL and MySQL each publish support information, why the words differ, and what to record when you plan an upgrade around a date.
Troubleshooting guide
Before you change a version, record what your tests say today
A baseline run turns 'the upgrade broke it' into evidence. Three honest baseline states, what a green suite does not cover and what to do when there are no tests.