canonical: https://jentic.com/apis/sendgrid.com/twilio-sendgrid-legacy-marketing-campaigns-contact

# Sendgrid Twilio SendGrid Legacy Marketing Campaigns Contacts API

The Twilio SendGrid Legacy Marketing Campaigns Contacts API allows you to manage your marketing contacts programmatically. This API is operational, but we recommend using the current version of Marketing Campaigns' [Contacts API](https://docs.sendgrid.com/api-reference/contacts/), [Lists API](https://docs.sendgrid.com/api-reference/lists/), and [Segments API](https://docs.sendgrid.com/api-referenc. The API exposes 36 endpoints secured with bearer authentication.

## For AI agents

Programmatically create a custom field, retrieve all custom fields. Covers 36 operations with bearer authentication.

## Scope

Does not handle payments, communications, or crm - use for marketing only.

## Capabilities

- Create a Custom Field
- Retrieve all custom fields
- Delete a Custom Field
- Query and filter Twilio SendGrid Legacy Marketing Campaigns Contacts API records by parameters
- Monitor Twilio SendGrid Legacy Marketing Campaigns Contacts API operational status and events

## Use cases

### Marketing Operations

Use the Twilio SendGrid Legacy Marketing Campaigns Contacts API to perform marketing operations programmatically. The API provides 36 endpoints covering core functionality including create a custom field, retrieve all custom fields, retrieve a custom field.

Example prompt: Call POST /v3/contactdb/custom_fields to create a custom field

### Automated Custom Fields Management

Automate custom fields operations by combining multiple Twilio SendGrid Legacy Marketing Campaigns Contacts API endpoints. Agents can retrieve all custom fields and then retrieve a custom field in a single workflow.

Example prompt: Call GET /v3/contactdb/custom_fields to retrieve all custom fields, then verify the result

### AI Agent Integration via Jentic

AI agents discover and call Twilio SendGrid Legacy Marketing Campaigns Contacts API endpoints through Jentic without managing credentials directly. An agent searches for the required operation by intent, receives the matching endpoint schema, and executes the call with Jentic-managed authentication. This eliminates the need to read API documentation or handle bearer tokens manually.

Example prompt: Search Jentic for 'create a custom field', load the operation schema, and execute with Jentic-managed credentials

## Key endpoints

| Method | Path | Description |
| --- | --- | --- |
| POST | /v3/contactdb/custom_fields | Create a Custom Field |
| GET | /v3/contactdb/custom_fields | Retrieve all custom fields |
| GET | /v3/contactdb/custom_fields/{custom_field_id} | Retrieve a Custom Field |
| DELETE | /v3/contactdb/custom_fields/{custom_field_id} | Delete a Custom Field |
| POST | /v3/contactdb/lists | Create a List |
| GET | /v3/contactdb/lists | Retrieve all lists |
| DELETE | /v3/contactdb/lists | Delete Multiple lists |
| GET | /v3/contactdb/lists/{list_id} | Retrieve a single list |

## Key resources

- **Custom Fields** — Twilio SendGrid Legacy Marketing Campaigns Contacts: Custom Fields API
- **Lists** — Twilio SendGrid Legacy Marketing Campaigns Contacts: Lists API
- **Recipients** — Twilio SendGrid Legacy Marketing Campaigns Contacts: Recipients API
- **Segments** — Twilio SendGrid Legacy Marketing Campaigns Contacts: Segments API

## Why Jentic

- **Setup:** Wiring the Twilio SendGrid Legacy Marketing Campaigns Contacts API by hand means learning its bearer API key auth, pointing at the api.sendgrid.com host, and handling paging and retries across its many contact endpoints yourself. Through Jentic you install once, import the Contacts API from the API Directory, store the API key once, and your agent calls it.
- **Permission scoping:** This API puts the list and custom field ids in the URL path (/v3/contactdb/lists/{list_id}, /v3/contactdb/custom_fields/{custom_field_id}), so a rule can pin your agent to one list or field: it can read that resource and nothing else. You choose the operations it may call, so deleting a custom field or list is not included unless you add it.
- **Credential handling:** Your Twilio SendGrid API key is stored once, encrypted, by your own Jentic One instance and injected at execution time. It never enters the agent's prompt, logs, or context.
- **Discovery method:** Agents search Jentic by intent such as 'create a custom field' or 'add contacts to a list', and Jentic returns the matching Twilio SendGrid Contacts API operation with its input schema so the agent calls the right endpoint without browsing the reference docs.

## Related APIs

- **Mailchimp** — Alternative marketing API
- **Hubspot** — Alternative marketing API

## FAQ

### What authentication does the Twilio SendGrid Legacy Marketing Campaigns Contacts API use?

The Twilio SendGrid Legacy Marketing Campaigns Contacts API uses a Bearer token in the Authorization header. Through Jentic, these credentials are stored encrypted in your Jentic One instance and injected at execution time, so raw secrets never enter the agent context.

### Can I create a custom field with the Twilio SendGrid Legacy Marketing Campaigns Contacts API?

Yes. Use the POST /v3/contactdb/custom_fields endpoint. The API returns structured JSON responses that agents can parse and act on directly.

### What are the rate limits for the Twilio SendGrid Legacy Marketing Campaigns Contacts API?

Rate limits are not specified in the OpenAPI spec. Check the vendor documentation for current limits. Through Jentic, rate limiting is handled automatically with retry logic built into the execution layer.

### How do I create a custom field through Jentic?

Install the Jentic SDK with pip install jentic, authenticate through Jentic One, the self-hosted execution layer, then search for 'create a custom field'. Jentic returns the matching Twilio SendGrid Legacy Marketing Campaigns Contacts API operation with its input schema. Load the schema and execute the call - credentials are injected automatically.

### How many endpoints does the Twilio SendGrid Legacy Marketing Campaigns Contacts API have?

The Twilio SendGrid Legacy Marketing Campaigns Contacts API exposes 36 endpoints covering custom fields, lists, recipients operations.

### Can I limit what my agent is allowed to do with the SendGrid Marketing Contacts API?

Yes. Jentic One runs self-hosted, so your own rules decide which operations and credentials your agent may use. Because this API puts list and custom field ids in the URL path (for example /v3/contactdb/lists/{list_id} and /v3/contactdb/custom_fields/{custom_field_id}), you can pin the agent to a single list or field and let it read that resource and nothing else. You pick the operations it may call, so destructive actions like deleting a custom field or a list stay out of reach unless you explicitly grant them.