Frequently asked questions about Stamp0. Common questions about email storage, limits, features, and troubleshooting.

Find answers to commonly asked questions about Stamp0.

Email Storage

How long are emails stored?

Emails are stored for 30 days. After that, they're automatically deleted. The inbox remains active and can continue receiving new emails.

What's the email size limit?

Emails up to 25MB are accepted. Larger emails will be rejected by our mail servers.

Can I extend the storage period?

Currently, the 30-day retention period is fixed. Contact us if you have specific requirements for longer retention.

Inboxes

Is there a limit on the number of inboxes?

No, there's no hard limit on inboxes. Create as many as you need for your testing workflows.

What happens to deleted inboxes?

When you delete an inbox:

All associated emails are permanently deleted
The email address cannot be recovered
This action cannot be undone

Can I choose my inbox email address?

No, inbox addresses are randomly generated (e.g., abc123xyz@stamp0.com). This ensures uniqueness and prevents conflicts.

Email Domains

Can I use custom email domains?

Currently, all inboxes use the @stamp0.com domain. Custom domains are planned for a future release.

Can I send emails from Stamp0?

Not yet. Stamp0 is currently receive-only. Outbound email sending is planned for a future release.

Features

Does Stamp0 support attachments?

Attachment support is coming in a future release. Currently, email attachments are not stored or accessible.

Can I forward emails to another address?

Email forwarding is not currently supported but is on our roadmap.

Is there a webhook for new emails?

Webhooks for email events are planned for a future release. Currently, you need to poll for new emails using the API or SDK.

Team & Access

Can multiple team members access the same organization?

Yes! Invite team members via Organization Settings → Members. Each member can have different roles:

Role	Permissions
Owner	Full access, can delete org
Admin	Manage members, projects, settings
Member	View and create projects, inboxes

See Members documentation for details.

How do I transfer organization ownership?

Organization ownership transfer requires contacting support. We'll verify your identity and facilitate the transfer.

Testing & Integration

How do I test locally?

Create an API key in the console
Set the STAMP0_API_KEY environment variable
Use the SDK or API in your tests

export STAMP0_API_KEY=sk_live_your_key
export STAMP0_PROJECT_ID=prj_abc123
npm test

Is there a sandbox/test mode?

All inboxes are ephemeral by nature, so there's no separate sandbox. We recommend:

Create a "Development" project for local testing
Create a "CI" project for automated tests
Keep test data separate from production tests

How fast do emails arrive?

Emails typically arrive within 1-3 seconds of being sent. If you're testing and don't see an email:

Verify your application is actually sending the email
Check the inbox address is correct
Wait up to 30 seconds before assuming failure

Can I use Stamp0 with any email-sending service?

Yes, Stamp0 works with any service that can send email:

Transactional email (SendGrid, Postmark, SES, etc.)
SMTP servers
Application-generated emails
Marketing platforms (for testing)

All data is encrypted in transit (TLS)
Data is encrypted at rest
API keys use secure random generation
We don't store or log email contents beyond the 30-day retention

Can I delete all my data?

Yes, you can:

Delete individual emails
Delete inboxes (deletes all emails)
Delete projects (deletes all inboxes)
Delete your organization (deletes everything)

We follow GDPR guidelines. Contact us for a Data Processing Agreement (DPA) if needed for compliance.

Troubleshooting

Emails not arriving?

Common causes:

Wrong address: Verify the inbox address is correct
Sending issue: Check your application is actually sending
Size limit: Emails over 25MB are rejected
Spam filters: Some senders may block stamp0.com addresses

API returning 401 Unauthorized?

Check:

API key is correct and complete
Key hasn't been deleted or disabled
Key has access to the project you're using
Authorization: Bearer header is formatted correctly

API returning 429 Too Many Requests?

You've hit the rate limit:

Wait for the limit to reset (check Retry-After header)
Reduce request frequency
Contact support for higher limits if needed

SDK timeout errors?

The waitForEmail function has a default 30-second timeout:

Increase the timeout if your emails are slow
Verify emails are actually being sent
Check for email delivery issues

Contact & Support

How do I get help?

Documentation: Browse our docs
Email: support@stamp0.com
Response time: We aim to respond within 24 hours

How do I report a bug?

Email support@stamp0.com with:

Description of the issue
Steps to reproduce
API responses or error messages
Your organization/project ID (if relevant)

How do I request a feature?

We love feedback! Email support@stamp0.com with your feature request. Include:

What you're trying to accomplish
How the feature would help
Any implementation ideas you have

Roadmap

What features are planned?

Upcoming features include:

Custom email domains
Outbound email sending
Webhooks for email events
Attachment support
Team roles and permissions improvements
GraphQL API

Priorities may change based on user feedback. Let us know what matters most to you!

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