> ## Documentation Index
> Fetch the complete documentation index at: https://ahasend.com/docs/llms.txt
> Use this file to discover all available pages before exploring further.

> ## Agent Instructions
> AhaSend stores all message data in the EU. See /facts.
> The API base URL is https://api.ahasend.com. Send the API key in the Authorization: Bearer header. See /api-reference/authentication.
> Use send.ahasend.com for SMTP in the EU, or send-us.ahasend.com as a US connection point forwarding to the EU. Ports 25, 587 and 2525 use STARTTLS. Port 465 is not supported. See /smtp.
> For send-only integrations, create an API Key v2 under Credentials → Add and scope it to messages:send:{your-domain}. See /send-api/credentials and /api-reference/scopes.

# API Error Codes and Error Responses

> Reference for AhaSend API v2 HTTP status codes (400, 401, 403, 404, 409, 422, 429, 500), the JSON error format, example messages, and how to fix each one.

AhaSend API errors use an HTTP status and a JSON message; this reference explains status codes and how your application should handle them.

## Error Response Format

All API errors return a consistent JSON structure with an HTTP status code and a descriptive message:

```json theme={null}
{
  "message": "Error description explaining what went wrong"
}
```

The `message` field is human-readable text, not a stable error code. Use the HTTP status and the operation's contract for program logic.

## HTTP Status Codes

The AhaSend API uses standard HTTP status codes to indicate the success or failure of requests:

### 2xx Success

* **200 OK** - Request succeeded
* **201 Created** - Resource created successfully
* **202 Accepted** - Message accepted for processing; inspect each recipient's status

### 4xx Client Errors

#### 400 Bad Request

Returned when the request is malformed or contains invalid parameters.

<Warning>
  Common causes include invalid JSON, missing required fields, or parameters that don't meet validation requirements.
</Warning>

**Example scenarios:**

* Invalid UUID format for `account_id` or resource IDs
* Malformed email addresses
* Invalid time formats (expecting RFC3339)
* Parameters outside allowed ranges (e.g., `limit` not between 1-100)
* Invalid domain names or URLs
* Malformed request body

```json theme={null}
{
  "message": "invalid account_id"
}
```

```json theme={null}
{
  "message": "invalid from_time, provide a valid RFC3339 time string"
}
```

#### 401 Unauthorized

Authentication failed or is missing.

**Common causes:**

* Missing `Authorization` header
* Invalid API key format (must be `Bearer <api_key>`)
* API key doesn't exist or has been revoked
* Account associated with API key is suspended
* API key doesn't belong to the specified account

```json theme={null}
{
  "message": "Missing or malformed bearer token"
}
```

```json theme={null}
{
  "message": "Invalid API key"
}
```

```json theme={null}
{
  "message": "Account is suspended"
}
```

#### 403 Forbidden

Authentication succeeded, but you don't have permission to access the resource.

<Tip>
  This typically occurs when your API key doesn't have the required scopes for the operation you're trying to perform.
</Tip>

**Common causes:**

* API key lacks required scopes (e.g., trying to delete domains without `domains:delete:all` or `domains:delete:{domain}` scope)
* Attempting to access resources outside your API key's domain restrictions
* Insufficient permissions for specific operations

```json theme={null}
{
  "message": "Insufficient permissions for the required scope"
}
```

```json theme={null}
{
  "message": "api key does not have sufficient permissions to read webhooks"
}
```

#### 404 Not Found

The requested resource doesn't exist or you don't have access to it.

**Common scenarios:**

* Resource ID doesn't exist
* Resource was deleted
* Resource belongs to a different account

```json theme={null}
{
  "message": "account not found"
}
```

```json theme={null}
{
  "message": "domain not found"
}
```

#### 409 Conflict

The request conflicts with the current state of the resource.

**Common causes:**

* **Idempotency conflicts**: Another request with the same idempotency key is already in progress
* **Resource conflicts**: Trying to create a resource that already exists (e.g., duplicate domain)
* **IP allow list conflicts**: Updating your own key would exclude the caller's current IP

```json theme={null}
{
  "message": "A request with this idempotency key is already in progress"
}
```

```json theme={null}
{
  "message": "domain already exists"
}
```

#### 422 Unprocessable Entity

The same idempotency key was used with a different method, resolved path, or request body. Use a new key for a new request, or retry the original request unchanged. See [idempotency](/docs/api-reference/idempotency).

#### 429 Too Many Requests

You've exceeded the API rate limits.

<Tip>
  When you receive this error, wait before making additional requests. Use exponential backoff with jitter. See [API rate limits](/docs/api-reference/rate-limits); rate-limit headers are not a documented contract.
</Tip>

```json theme={null}
{
  "message": "Too many requests, rate limited."
}
```

### 5xx Server Errors

#### 500 Internal Server Error

An unexpected server error occurred on our side (these are rare).

<Danger>
  These errors indicate a problem on our end. If you consistently receive 500 errors, please contact support.
</Danger>

```json theme={null}
{
  "message": "Internal server error"
}
```

```json theme={null}
{
  "message": "internal server error, please try again later"
}
```

## Validation Errors

When request validation fails, you'll receive a `400 Bad Request` with a descriptive message:

### Request Body Validation

```json theme={null}
{
  "message": "invalid request body"
}
```

### Field-Specific Validation

The API provides specific validation messages for individual fields:

```json theme={null}
{
  "message": "invalid domain name, please provider a valid fully qualified domain name."
}
```

```json theme={null}
{
  "message": "limit must be between 1 and 100"
}
```

### Security-Related Validation

```json theme={null}
{
  "message": "domain is banned to protect our network from abuse and spammers. if you think this is an error please contact support"
}
```

## Scope and Permission Errors

When your API key doesn't have sufficient permissions:

### Missing Scopes

```json theme={null}
{
  "message": "sender domain not found in api key scopes"
}
```

### Invalid API Key Context

```json theme={null}
{
  "message": "invalid api key context"
}
```

## Best Practices

### Error Handling

* Always check the HTTP status code first
* Show the `message` field to people; do not branch on its text, which can change
* Implement appropriate retry logic for 5xx errors
* Respect rate limits when receiving 429 responses

### Common Fixes

* **400 errors**: Validate your request parameters and JSON structure
* **401 errors**: Check your API key and authentication headers
* **403 errors**: Verify your API key has the required scopes
* **404 errors**: Confirm the resource exists and belongs to your account
* **429 errors**: Implement exponential backoff in your retry logic

<Note>
  Error messages are designed to be descriptive and actionable. They provide specific guidance on what needs to be corrected in your request.
</Note>

## Related Guides

* [API authentication](/docs/api-reference/authentication), [Permission scopes](/docs/api-reference/scopes), [Send-only API keys](/docs/send-api/credentials).
* [REST sending guide](/docs/send-api/send-email), [SMTP settings](/docs/smtp), [CLI quickstart](/docs/cli/quickstart).
* [Node.js SDK](/docs/guides/nodejs-sdk), [Go SDK](/docs/guides/go-sdk), [Idempotency rules](/docs/api-reference/idempotency).
* [API rate limits](/docs/api-reference/rate-limits).


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