# Best Practices

## Check each email

Keep individual checks on Gmail, Outlook, and iCloud. Two addresses at the same provider can have different [plus-alias verdicts](https://docs.disify.com/api/plus-alias.md), so a domain result must not replace an email check. Preserve plus tags and Gmail dots when sending the address.

## Use the API verdict

Use `disposable` as the disposable verdict. `whitelist: true` describes the provider and does not override it. Treat a custom [confidence threshold](https://docs.disify.com/api/confidence.md#choosing-a-threshold) as a deliberate product policy, not a required integration step.

For paid [privacy-relay rejection](https://docs.disify.com/api/forwarding.md), also require `blocked === false`. A relay can be blocked while `disposable` is false; missing or `null` is not an allow decision. Continue checking `format` and `dns` separately.

## Distinguish failures from validation results

Check HTTP status and response types first. A `format: false` result may omit later checks; a valid-format result with missing `disposable` or `dns` is unexpected. Optional fields can be absent. See [Response Fields](https://docs.disify.com/api/response-fields.md).

The `dns_indeterminate` signal means DNS was inconclusive. Do not treat it as confirmed absence of mail servers. Decide how the application handles unavailable checks, and retain email ownership verification where required.

## Bound requests and retries

Use backend POST requests with proper form encoding, a timeout, and server-only API keys. Check at submission rather than every keystroke. Respect `Retry-After` on per-minute limits and `reset_at` on quota exhaustion. Use bounded retries with jitter for temporary failures. See [Error Handling](https://docs.disify.com/api/errors.md).

## Cache and batch deliberately

If caching email results, include the full input, requested features, and API-key context. Invalidate cached results when the plan or account/key settings change, and distinguish request overrides. Set an expiry and exclude errors and inconclusive results. Detection data can change.

For large lists, use [bulk validation](https://docs.disify.com/api/bulk.md) and handle both synchronous and queued responses. Test integrations with mocked responses; the [agent guide](https://docs.disify.com/guide/agents.md#test-the-integration) lists useful cases.

---

Questions or issues? [Open a support ticket](https://disify.com/account/support) from your account and we'll help you out.

Source: https://docs.disify.com/resources/best-practices.html