Shared Resend Portfolio

Shared Resend Portfolio

Implement email for multiple products through one Resend account and verified domain. Optimize for a solo developer or small portfolio using the free tier without making every app look like the same product.

Core model

Share infrastructure, not product identity:

One Resend account
└── Existing verified sender domain
    ├── Product A sender identity
    ├── Product B sender identity
    └── Product C sender identity

Each app keeps its own:

• sender display name
• destination inbox
• Reply-To routing
• subject conventions
• branded HTML and plain-text templates
• deployment environment variables
• delivery logs and failure behavior

All apps share the account-level free-tier quota and verified-domain reputation.

Portfolio discovery

Before implementation:

1. Inspect the target app and any sibling app with a working Resend setup.
2. Identify the canonical Resend account and already verified domain.
3. Confirm the product display name, shared sender mailbox, internal recipient, support Reply-To inbox, and expected email types.
4. Confirm whether the target deployment already has a Resend API key.
5. Do not ask the user to create another account, verify another domain, or buy a plan unless the existing account cannot meet a stated requirement.

Account and key strategy

Reuse the same Resend account and verified domain. Prefer a separate API key per deployed app when the account permits it; this limits the impact of a leaked or rotated key while remaining on one account and quota. Reuse the same key only when separate keys are unavailable or the user explicitly prefers that trade-off.

Never copy secrets from another repository into source control. Add the selected key directly to each deployment’s secret environment.

Per-product configuration

Use server-only variables and product-specific names where practical. Resolve their values from the user's existing Resend account, verified sender configuration, and intended product inbox—never copy example identities into an implementation.

The visible display name supplies product identity; the existing verified address supplies deliverability. Never use a NEXT_PUBLIC_ or equivalent client-exposed variable for an API key.

Contact-form routing

Send two separate messages:

Internal notification
From: configured product sender identity
To: configured internal product inbox
Reply-To: validated address submitted by the visitor

Visitor confirmation
From: configured product sender identity
To: validated address submitted by the visitor
Reply-To: configured internal product inbox

Do not put the visitor and internal inbox in one recipient list. Separate messages prevent address exposure and allow different content.

Treat the internal notification as primary delivery. Return form success only after Resend accepts it and returns a message ID. Attempt visitor confirmation afterward; log its failure without claiming the primary enquiry was lost.

Brand isolation

Create a distinct template shell for each product while keeping the provider module pattern reusable. Customize:

• product name and descriptor
• colors, typography, and header treatment
• email preview text
• subjects and tone
• footer ownership, support address, and response expectations

Use table layouts, inline CSS, a 600–640px content width, escaped user values, and a plain-text version. Do not reuse another product’s visual identity merely because the sender infrastructure is shared.

Shared free-tier safeguards

• Check the current Resend free-tier limits rather than relying on remembered numbers.
• Remember that every app consumes the same account quota.
• Send only necessary transactional messages; avoid duplicate notifications.
• Keep anti-spam controls on public forms: validation, length limits, honeypot, and rate limiting where appropriate.
• Avoid retry loops that can send duplicates. Persist or use idempotency where the workflow has meaningful retry risk.
• Monitor provider rejections and quota errors without logging secrets or unnecessary personal data.
• Escalate to another account or paid plan only when measured volume, isolation, compliance, or reputation requirements justify it.

Reliable implementation

1. Install the official resend package in the correct workspace.
2. Keep provider calls in a server-only module.
3. Validate result.data?.id and ensure result.error is absent.
4. Catch SDK and network exceptions.
5. Set replyTo explicitly.
6. Return 503 when email is not configured and 502 when primary delivery fails.
7. Preserve direct email, phone, or messaging fallbacks in the UI.
8. Never report log-only handling as successful delivery.

Verification

• Confirm the shared domain is verified in the reused Resend account.
• Confirm the product-specific From, To, and Reply-To values.
• Test internal delivery, then visitor confirmation, then replying in both directions.
• Test validation, honeypot, missing-key, provider-rejection, and fallback paths.
• Run repository-native typecheck, lint, test, and build commands.
• Confirm the deployment contains its API key and product variables.
• Perform one real submission before claiming live delivery works.