Flow errors

Error Handling & Recovery Flows

Overview

An error state is a fork where the product either keeps the user's trust and work, or loses both. Every error must answer three questions: what happened (in human terms), how to fix it, and where the user's work went — and the answer to the last one must be "nowhere, it's safe."

When to Use

• Building any surface that can fail: forms, saves, payments, uploads, network calls, agent runs
• Adding delete, archive, cancel, overwrite, or send actions
• Designing offline or flaky-network behavior; building 404/500 pages
• NOT for: validation timing and error summaries inside forms — see flow-forms
• NOT for: logging/observability plumbing with no user-facing surface

The Proven Flow

1. Failure is caught; work is preserved first. Before any message renders, the user's input and state are held: form values stay in their fields, drafts persist locally, uploads keep partial progress, unsaved edits go to local storage. Preservation precedes messaging — a perfect error message over lost work is still a catastrophe. Gmail keeps the draft through any send failure; Figma holds every offline edit.
2. The message renders at the point of failure. Inline next to the failed field or object if the error is local. Banner at the top of the affected region if it blocks the whole task. Toast only if the failure is non-blocking and self-explanatory. The message states human cause + concrete fix: "Couldn't save — you're offline. We'll retry automatically; your changes are stored on this device."
3. A recovery action ships with every message. Retry button, "Edit and resend," jump-link to the fixable field, or "Contact support" with the error reference pre-attached. An error without an affordance is a dead end, and dead ends convert to rage-refresh and churn.
4. Retries are visible. Automatic retry with backoff shows its state: "Retrying in 5s… · Retry now." A silent spinner during retries reads as a hang and triggers duplicate actions elsewhere. Cap visible auto-retries (~3 attempts), then hand control to the user: manual retry + persistent status.
5. Success after failure confirms reconciliation. "Back online — all changes saved" (Figma, Linear). The user must learn the queue flushed, not merely notice the warning banner disappeared. Brief, then gone.
6. Destructive actions are protected before an error can exist. Default: perform the action optimistically, then offer undo in a toast with a visible window (Gmail undo-send: 5–30s user-configurable). Confirmation dialogs only where undo is technically impossible — and then they name the consequence, never just "Are you sure?"
7. Total failures get honest full pages. Route missing → 404 with exits. Server down → 500 with a reference ID and a status link. Both keep global navigation so the user is lost on a page, not lost in the product.

Layout & Structure

Display-surface decision rules

Surface	Use when	Rules
Inline (below field/object)	Error is local to one input or item	Red text + icon, 4–8px below the element; focus moves to first error on submit
Banner (top of page/region)	Blocks the current task; must persist	Stays until resolved or dismissed; contains the fix action; never auto-dismisses
Toast / snackbar	Non-blocking, informational, or undo-carrier	Auto-dismiss 5–10s; never the sole surface for an error requiring action; never for payment or permission failures
Full page	Nothing on this route can render (404, 500, no access)	Anatomy below; global nav intact
Modal	Almost never for errors	Only when the user must decide before anything else can proceed

Error message anatomy (every message, every surface)

1. What went wrong, in the user's vocabulary — name the object ("Couldn't upload invoice.pdf"), never the subsystem ("Request failed: 422").
2. Why, if known and useful ("The file is over the 25 MB limit").
3. What to do next, phrased as an action ("Compress it or choose a smaller file").
4. Where their work is, whenever work is at stake ("Your other 3 files uploaded fine").

Never: raw status codes as the headline; blame framing ("You entered an invalid…" → "We couldn't match that…"); ALL-CAPS or exclamation marks; "Oops!" cuteness on high-stakes failures. The error code belongs in small text for support reference, not in the headline.

Copy examples: bad → good

Bad	Good
"Error 422: Unprocessable entity"	"Couldn't save — that project name is already taken. Try a different name."
"Payment failed"	"Your card was declined by your bank. No charge was made. Try another card or contact your bank."
"Upload error"	"invoice.pdf is 32 MB — the limit is 25 MB. Compress it or split it into parts."
"Session expired"	"You were signed out after 30 minutes of inactivity. Sign in again — your entries are saved."
"Network error occurred"	"Can't reach the server — check your connection. We'll keep retrying; your draft is saved on this device."
"Permission denied"	"You need editor access to change this. Ask Maria (owner) or request access."

Severity → surface mapping

Severity	Example	Surface
Field-level	Bad postcode	Inline below field
Task-blocking	Card declined, no permission	Persistent banner + fix action
Degraded service	One integration down, rest works	Dismissible banner, scoped to the affected feature
Non-blocking	One background sync retried fine	Toast, or nothing
Route-fatal	404, 403	Full page with exits
System-fatal	500, outage	Full page + reference ID + status link

Full-page anatomy

• 404: plain statement ("This page doesn't exist or has moved") + search box + links to the 3–5 most likely destinations + normal global nav. Never a bare joke with no exits.
• 500: "It's a problem on our end, not yours" + auto-generated incident/reference ID + link to the status page + an explicit "your data is safe" statement when true + a retry action. GOV.UK's error pages are the canon: no branding jokes, maximum clarity, calm register.
• 403/permission: state what's restricted and the path to access (request access button, who to ask) — not a bare "Forbidden."

Destructive action protection (in order of preference)

1. Undo beats confirm. Execute immediately, show a toast with "Undo" for 5–30 seconds (Gmail undo-send; Linear's delete-issue undo). Applies to delete, archive, send, move, and bulk edits. Confirms interrupt everyone to protect against a rare mistake; undo protects only the mistaken, at the moment of mistake.
2. Soft-delete / trash with ~30-day recovery for containers: projects, boards, documents, files. Undo covers seconds; trash covers "realized on Tuesday."
3. Confirm only when truly irreversible (permanent purge, account deletion, prod deploy). The dialog names object and consequence: "Delete 'Q3 Report' and its 14 pages? This can't be undone." Generic "Are you sure?" trains blind clicking and carries zero information.
4. Type-to-confirm (repo name, the word DELETE) reserved for the highest tier — GitHub repo deletion. Overuse destroys the signal.
5. Button mechanics: destructive actions styled distinctly (red), never the default/focused action (Enter must not destroy), never placed adjacent to a frequent safe action.

Offline handling

• Detect and announce once: a persistent, subtle indicator ("Offline — changes saved on this device"), not a blocking modal and not a re-toasting loop.
• Queue mutations locally with per-item pending state (Linear's offline queue). Persist the queue to local storage/DB — queued writes must survive tab close and app restart.
• Keep reads alive from cache. Never disable the whole app when cached content could render.
• On reconnect: sync automatically, confirm briefly ("Back online — synced"); auto-merge non-conflicting changes at operation/field level (Figma, Google Docs); show the both-versions picker only for true conflicts on the same content — never silent last-write-wins.

Partial failure

• When a batch half-succeeds, report per-item: "7 of 9 files uploaded · 2 failed — Retry failed items." Never collapse a batch into one merged spinner→error, and never re-run the successes on retry.
• Same rule for multi-step agent/import flows: name which steps completed; retry resumes, not restarts.

Form data preservation

• Values survive server errors, session expiry, and navigation. Session-expired flow: keep the form rendered, re-authenticate in a modal or side flow, return to the intact form. Losing a long form to a login redirect is a top-3 rage trigger.
• On browser back / accidental close with unsaved changes: restore drafts on return (preferred) or warn before unload (fallback).

Accessibility

• Blocking errors announce via role="alert" / aria-live="assertive"; toasts via aria-live="polite".
• On failed submit, focus moves to the error summary or first errored field; never trap focus in an error state without an escape.
• Undo must be keyboard-reachable within its window; for critical undo, pair the toast with a persistent path (Edit menu, trash).
• Error state is never color-alone: icon + text alongside red.
• The offline indicator lives in the accessibility tree with a text label, not as a decorative dot.

Metrics that prove recovery works

• Retry success rate (auto and manual) — low manual-retry success means the message promises a fix it can't deliver.
• Undo usage rate on destructive actions — near-zero may mean the window is too short to catch mistakes.
• Support tickets quoting error text — each one is a message that failed to self-serve.
• Rage-refresh / repeated-submit within 10s of an error — the signature of a dead-end error state.

Quick Reference

Situation	Pattern
One field failed	Inline error below field + move focus
Whole-task blocker (payment declined, permission)	Persistent banner with fix action
Non-blocking hiccup	Toast, auto-dismiss 5–10s
Delete / send / archive	Do it + undo toast (5–30s window)
Deleting a container (project, doc)	Soft-delete to trash, 30-day recovery
Truly irreversible destruction	Consequence-naming confirm; type-to-confirm at highest tier only
Network call failed	Auto-retry with visible countdown, cap ~3, then manual
Went offline	Persistent indicator + local queue + cached reads
Back online	Auto-sync + brief "synced" confirmation + explicit conflict UI
Batch partially failed	Per-item results + retry-failed-only
Server error on form submit	Preserve all values + banner with cause + retry
Session expired mid-form	Re-auth in place, return to intact form
Payment failed	Banner: bank's reason + "no charge was made" + try-another-card
Upload failed midway	Keep partial progress; resume, don't restart
Route not found	404: statement + search + likely links + nav
Server down	500: reference ID + status link + "data safe" + retry

Anti-Patterns

Anti-pattern	Why it breaks	Fix
"Something went wrong" with no action	Dead end; only move is rage-refresh	Cause + fix + retry, always
Blocking error shown only in a 5s toast	Vanishes before it's read or acted on	Persistent inline/banner for anything requiring action
Confirm dialog on every delete	Trains blind confirmation; still loses data	Undo-first; confirms only for irreversible
"Are you sure?" with no object or consequence	Carries zero information	Name what's deleted and what's unrecoverable
Form cleared on server error	Destroys work to report a failure	Values survive every error class
Silent auto-retry forever	Looks frozen; user duplicates action elsewhere	Visible retry state, capped, then manual control
Raw exception / stack / status code shown	Meaningless and alarming	Human message; code in fine print for support
Offline = whole app disabled	Punishes reads cache could serve	Cached reads + queued writes + indicator
Queued offline writes lost on tab close	Betrayal discovered later	Persist the queue durably
Sync conflicts silently overwritten	Data loss found weeks later	Explicit both-versions conflict UI
Batch error as one blob	Can't tell what succeeded; retry duplicates	Per-item status, retry-failed-only
Red destructive button as default focus	Enter key destroys data	Safe action is default; destructive needs deliberate selection
Undo toast under 5 seconds	Gone before the mistake registers	5–30s window; pair with trash for containers
Repeated failures spawn stacked toasts	Notification spam buries the actual problem	Coalesce into one updating banner with count
Error modal steals focus mid-typing	User's keystrokes hit the dialog's buttons	Non-modal surfaces for anything not requiring a decision
Same visual style for errors, warnings, promos	Users learn to dismiss everything red-ish	Reserve the error style for errors only
Joke-heavy 500 during an outage	Reads as mockery when work is lost	Plain, calm, reference ID, status link

Proven by: GOV.UK Design System (error messages, error pages), Gmail (undo send, draft preservation), Figma (offline editing, reconnect sync), Linear (offline queue, optimistic updates + undo), GitHub (type-to-confirm tiering).