Seamless API Overview

What is the Seamless API?

The Seamless API gives your team direct, programmatic access to our real-time contact and company data, without using the Seamless app interface.

With the API, you can:

• Search for leads using filters like job title, company size, industry, and location
• Enrich incomplete records with verified contact and company details
• Sync searched or enriched data directly into your CRM or internal systems
• Automate lead workflows through tools like Salesforce, HubSpot, Clay, n8n, and other systems

The API is ideal for teams that want to scale, automate, and customize their lead generation, enrichment, and CRM data workflows.

Learn more about the API and view related documentation here: https://docs.seamless.ai/

Integration Options Overview

The Seamless API supports multiple authentication and integration methods to fit your organization’s needs:

Persistent API Keys

Persistent API Keys provide a long-lived, stable authentication method for connecting to the Seamless API.

Persistent Keys are recommended for most standard API use cases because they:

• Provide a direct and secure connection to the API
• Do not require refresh tokens
• Are easy to manage
• Work well with platforms like Salesforce, Clay, n8n, MCP, and internal systems

OAuth with Refresh Tokens

OAuth uses session-based authentication and requires regular refreshing of tokens to maintain active connections.

OAuth may be preferred when your organization needs tighter control over session lifecycles or user-specific access.

Webhooks

Webhooks are used with research endpoints to automatically send completed research results to your system.

With webhooks, you can include webhook details in the request header so Seamless sends completed research results to your delivery URL automatically.

These methods can be used individually or in combination. For example, you can run Persistent Keys for steady integrations while using Webhooks for event-based triggers. Persistent Keys work alongside the other methods, with separate limits of up to 25 keys each. Your current OAuth tokens and Webhook configurations remain active and unaffected.

Admin Controls & Visibility

• Organization-Wide Management: Admins can view and manage all API keys created by users in their org.
• User Privacy: Users cannot view or manage each other’s keys.
• Limits: Each method (Persistent Keys and OAuth) supports up to 25 active keys per organization. With the recent addition of 25 Persistent Key slots, organizations effectively have the capacity to run up to 50 requests.

API Credits Breakdown

The Seamless API uses Universal Credits only. API usage is not available for use with search credits. 

Credits are consumed based on the API action being performed. View the breakdown of API actions and related Universal Credit usage: 

• Contact research = 1 credit per contact researched
• Company research = 1 credit per company researched
• Search = 1 credit per 10 returned results
  
  • Credits for search results are rounded up, for example: ‍
    • Search with fewer than 10 results = 1 credit‍
    • Search with 11 results = 2 credits

Credit usage is tied to the owner of the API key. If a user creates the API key, activity and credit usage through that key is associated with that user.

Avoiding Duplicate Research Charges

Research endpoints include a deduplication option to help avoid researching the same contact or company more than once.

When deduplication is enabled, Seamless checks whether the user has already researched the submitted contacts or companies.

For example, if 6 contacts are submitted and 3 have already been researched, Seamless only researches the 3 new contacts.

Use deduplication when you want to avoid duplicate research usage.

Rate Limits

The standard Seamless API rate limit is: 60 requests per minute

Design bulk search, enrichment, and automation workflows to stay within this limit.

Key Capabilities of the Seamless API

There are many efficient and effective use cases and key capabilities to use the Seamless API Key. Some include: 

• Search Contacts & Companies - Build targeted lists programmatically to power internal tools and campaigns.
• Enrich Data - Provide partial inputs and receive enriched, verified records for CRM cleanup and segmentation.
• Sync Data - Automatically deliver enriched or searched data into your CRM, marketing platform, or other internal tools.‍
• Trigger Actions (Webhooks) - Receive real-time notifications and instantly act on events as they happen.

How to Get Started

Seamless Users with an API License can access, manage, and set up new API Connection in their Settings. Manage and create API connections based on your needs from the  “Webhooks” page or “Public API Connections” page under Company Settings.  

Step 1: Define Your Use Case

Decide whether you need to:

• Search for new contacts or companies
• Enrich existing records
• Sync data into another system
• Trigger actions when research is completed

You should also identify the fields and endpoints you plan to use, such as title, phone number, company size, industry, or domain.

Step 2: Set Up the API

Review the API documentation, choose your authentication method, and create the appropriate connection.

• Choose your preferred integration method(s): Persistent Key, OAuth, and/or Webhooks.
• Obtain your key or configure OAuth and/or Webhook endpoints.
• Work with your development team to connect Seamless to your systems (e.g., Salesforce, HubSpot, Marketo).

Additional API Documentation available here: https://docs.seamless.ai/

Step 3: Test Your Workflow

Start with a small data sample before scaling.

• The request body is formatted correctly
• Filters are returning the expected results
• Credits are being used as expected
• Scale into additional use cases (e.g., lead routing, campaign prep, database refresh).

Step 4: Launch and Monitor

After testing, scale your workflow gradually and monitor usage, returned records, and credit consumption.

What Data Can Be Returned?

When using the API, you’ll receive a comprehensive set of contact and company data fields:

Contact Details

• Full Name, Title, Department, Seniority
• Primary & Alternate Emails (with validation scores)
• Direct Dials & Mobile Numbers
• Location: City, State, Country, ZIP

Company Details

• Company Name, Website, Domain
• Size, Revenue, Industry, SIC/NAICS Codes
• Headquarters Location, Tech Stack, Founded Date

Metadata & CRM Fields

• Import & Research Dates
• CRM Identifiers for syncing
• Lead Source Metadata

Common API Use Cases

• CRM Enrichment: Fill in missing contact and company data to improve segmentation, scoring, and CRM hygiene.
• Web Form Enrichment: Instantly enrich leads from form submissions for faster routing and follow-up.
• Campaign Segmentation: Build accurate, targeted lists using enriched data to improve marketing performance.
• Buying Committee Expansion: Discover additional stakeholders at key accounts to support multithreaded outreach.
• Data Refresh & Job Changes: Keep your CRM up to date by refreshing stale records and monitoring job changes.
• Automation Workflows: Use tools like n8n, Clay, Salesforce, HubSpot, or internal systems to automate repeatable search and enrichment workflows.

Tips for Success

• Start small: Focus on one automation or enrichment use case first
• Test your integration with a small data sample before scaling
• Regularly audit and validate enriched fields in your CRM
• Collaborate with your internal RevOps or development teams for best results

Learn more about Seamless API Terms here: Seamless API Terms Glossary

Common Troubleshooting Steps

API Access Issues

If API settings or API connections are not visible, confirm that:

• Your account includes API access
• You are logged into the correct Seamless organization
• You have the required permissions
• The API license is assigned to the correct user

Authentication Issues

If a request fails due to authentication, confirm that:

• The API key is active
• The key was copied correctly
• The correct authentication method is being used
• The API key owner has the required access
• The key has not been restricted or deactivated

Search Results Look Incorrect

If search results do not match expectations, review:

• The request body
• Exact field names
• Field formatting
• Required fields
• Valid dropdown values from the API documentation

Some fields, such as industry, may require a valid documented value. Invalid optional fields may be ignored rather than causing the full request to fail.

Credit Usage Looks Higher Than Expected

If credits are decreasing faster than expected, review:

• Whether the workflow is running search, research, or both
• How many records are being returned
• Whether duplicate records are being researched again
• Whether deduplication is enabled
• Whether the same automation is running repeatedly

Frequently Asked Questions

Do you offer API access to your contact data?

Yes. Seamless provides API access so customers can programmatically search, enrich, and manage contact and company data directly within their systems.

What types of data can be accessed through the API?

The API supports access to contact and company fields such as names, titles, emails, phone numbers, company attributes, and CRM metadata.

Is the API RESTful and what format is the data returned in?

Yes. The Seamless API follows REST principles and returns data in JSON format.

Can I use the API to enrich my CRM and search leads programmatically?

Yes. The API supports both enrichment of existing records and programmatic search using filters aligned to your ideal customer profile.

Does the API require Universal Credits?

Yes. The Seamless API uses Universal Credits only. Search and research actions require Universal Credits to return data.

Why did my search use a full credit if I only received 5 results?

Search credit usage rounds up. Searches consume 1 credit per 10 returned results, so 1–10 returned results consume 1 credit.

How do I avoid researching the same contacts twice?

Use deduplication on research requests. When deduplication is enabled, Seamless only researches contacts or companies that have not already been researched by that user.

Do campaign, task, or activity endpoints use credits?

No. Campaigns, tasks, activity, and other non-search or non-research actions do not use credits. Rate limits still apply.

Can I use the Seamless API with n8n?

Yes. Seamless API workflows can be connected to n8n using API keys and HTTP requests. Test the workflow with a small batch before scaling.

What is the API rate limit?

The standard API rate limit is 60 requests per minute.

Do I need a developer to use the API?

Yes. The API is designed for technical implementation and typically requires a developer, RevOps, or operations team member to set up and maintain the integration.

Support

Need help getting started or troubleshooting?
Contact Support and include the endpoint, request body, response body, error message, timestamp, and API key owner or OAuth user email. Or, share the developer documentation with your technical lead.

The Seamless API brings your CRM to life—automating enrichment, discovery, and syncing to keep your data fresh, complete, and ready to drive results.