How to Use the Platform’s API for Bulk DKIM Due Diligence
Email authentication is a central part of vendor, acquisition, and partner due diligence. A domain with a valid DKIM record can demonstrate better control over outbound email, while missing, outdated, or misconfigured keys may indicate operational weaknesses or create opportunities for spoofing.
Trusted Sender Score provides domain trust checks, DKIM and DMARC tools, bulk verification capabilities, and developer access for security workflows. Using the platform’s API, teams can assess many domains consistently instead of relying on manual DNS lookups and spreadsheets.
Bulk DKIM analysis is most useful when it becomes a repeatable process. A structured workflow can collect the target domains, submit checks, normalize results, investigate exceptions, and preserve evidence for later review.
Define the Due Diligence Scope
Begin by identifying which domains and subdomains are relevant to the review. Include corporate domains, domains used for marketing mail, customer notifications, transactional systems, and known third-party sending platforms. A company may use different DKIM selectors across separate services.
Clean the input list before sending requests. Remove duplicates, normalize capitalization, exclude malformed entries, and record the source of every domain. Useful metadata includes the business owner, acquisition status, email purpose, and date added to the review.
The API should be treated as an assessment layer rather than the only source of evidence. DNS records can change, so retain the check timestamp, request parameters, response data, and any relevant domain ownership notes.
Prepare Authentication and Request Handling
Review the platform’s API documentation for authentication requirements, endpoint paths, request fields, pagination, response formats, and rate limits. Keep API credentials in a secrets manager or protected environment variable rather than placing them in scripts, tickets, or shared spreadsheets.
A bulk process typically submits a domain or a batch of domains for DKIM inspection, then records the returned status and diagnostic details. If the API supports asynchronous jobs, store the job identifier and poll for completion according to the documented interval. Avoid aggressive retries that could trigger throttling.
Add safeguards for temporary failures. Exponential backoff, bounded retry counts, connection timeouts, and clear error logging help distinguish a network problem from an actual DKIM failure. A successful API response should also be separated from a successful authentication result.
Build a Repeatable Checking Workflow
A practical workflow divides results into technical states that reviewers can understand. The exact labels depend on the API response, but the following model gives a useful foundation:
| Result category | Typical meaning | Due diligence action |
|---|---|---|
| Valid DKIM | A published key is present and structurally usable | Record the selector, key type, and evidence timestamp |
| Missing record | No expected DKIM record was found | Confirm the sending service and request remediation |
| Invalid record | The record exists but has syntax or key problems | Investigate DNS formatting and deployment controls |
| Multiple or unexpected selectors | Several services may be signing mail | Map selectors to approved providers |
| Lookup or API error | The result could not be reliably determined | Retry, verify scope, and mark as unresolved |
Do not treat a valid public key as proof that every message from the domain is correctly signed. DKIM validation also depends on the selector used by the sender and the alignment policy applied by the receiving system. Compare the API result with mail-flow records, approved vendors, and the organization’s documented sending inventory.
For broader email security context, use the platform’s DMARC guidance to connect DKIM findings with SPF, alignment, enforcement policy, and reporting practices.
Normalize and Enrich the Results
Store raw responses separately from the reporting dataset. The raw record preserves the original evidence, while normalized fields make filtering and comparison easier. Suggested fields include domain, selector, status, key type, key length when available, error code, check time, source list, and reviewer disposition.
Flag conditions that deserve manual review. Examples include an expired business relationship, a selector associated with an unknown provider, a weak or unexpected key configuration, inconsistent results across repeated checks, or a domain that sends mail but has no visible authentication setup.
Domain reputation should be considered alongside DKIM. A domain may publish technically valid records while still showing signs of spoofing exposure, poor sender trust, or weak policy enforcement. The sender trust platform can help place DKIM findings within that wider risk assessment.
Protect Evidence and Control Access
Due diligence data may include sensitive vendor information, internal domain inventories, or security findings. Limit access to API keys and reports according to role, and avoid logging credentials in request traces. Encrypt stored outputs and define retention rules before launching a large review.
Preserve evidence in a way that another analyst can reproduce. Keep the input file, script version, API documentation version, timestamps, and response identifiers where available. When a finding leads to remediation, store the updated result rather than overwriting the original observation.
A review is stronger when technical findings are tied to business impact. For example, a missing DKIM record on a dormant domain may be low priority, while an invalid selector on a domain used for invoices or password resets could warrant immediate escalation.
Apply Practical Review Controls
Use these controls to make bulk DKIM verification reliable and auditable:
- Validate and deduplicate domain inputs before submitting API requests.
- Respect documented rate limits and implement bounded retries for transient errors.
- Keep raw API responses alongside normalized assessment fields.
- Map selectors and sending providers to known business owners.
- Recheck high-risk or remediated domains and retain both result sets.
Automate notifications only after result categories have been tested against real responses. A parser that assumes every response contains the same fields can silently misclassify errors as failed authentication or overlook an important diagnostic.
The final report should distinguish confirmed findings, unresolved checks, and informational observations. Include the review date and clearly state that DNS and authentication status can change after collection.
Use the platform’s API to turn one-time domain inspection into a defensible due diligence process. Start with a controlled sample, validate the response handling, then expand to the full domain inventory while preserving evidence at every stage.