Google Gmail Postmaster Tools API
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For Agents
Pull Gmail deliverability data for verified sending domains, including spam rates, IP and domain reputation, and authentication pass rates.
Use for: Get Gmail spam rate for my sending domain over the past 30 days, Check domain reputation for a verified Postmaster Tools domain, Retrieve DKIM and SPF pass rates for mail sent to Gmail, List all domains registered in our Postmaster Tools account
Not supported: Does not send mail, manage Gmail mailboxes, or register new domains — use for reading deliverability metrics on already-verified sending domains only.
The Gmail Postmaster Tools API gives high-volume senders programmatic access to deliverability metrics that were previously only viewable in the Postmaster Tools UI. Senders can pull spam rates, IP and domain reputation, authentication results (SPF, DKIM, DMARC), feedback loop identifiers, and delivery error breakdowns for domains they have verified. The data is aggregated daily and is intended to help senders diagnose deliverability problems before they become reputation-damaging. The API exposes domain registration metadata along with per-day traffic statistics for each verified sending domain.
Install Jentic One Beta
Connect the Gmail Postmaster Tools API to your agent
Jentic One is a self-hosted execution layer for AI agents. It lets your agent call the Gmail Postmaster Tools API, or any other public or private API you need. You set the rules, the agent never sees your credentials, and every call is logged.
Two steps, two machines. Install the instance in a safe environment, then register your agent from wherever it runs.
1
Step 1: Jentic One Host machine
# On the machine that will host your Jentic One instance:
curl -fsSL https://raw.githubusercontent.com/jentic/jentic-one/main/tools/install.sh | sh2
Step 2: Agent machine
# On the machine where your agent runs (keep this separate from the instance):
curl -fsSL https://raw.githubusercontent.com/jentic/jentic-one/main/tools/install.sh | sh
jentic register # connects your agent to your Jentic One instanceJentic One is in public beta. The setup above keeps your agent separate from the instance, which is what you want before using real credentials: an agent running as the same OS user as Jentic One can read its stored keys directly. Just evaluating? A single local install is fine to start. See the secure deployment guide for the tiers.
Capabilities
What an agent can do with Gmail Postmaster Tools API.
List verified sending domains registered to the authenticated postmaster account
Retrieve registration details and verification status for a specific Gmail Postmaster domain
Fetch daily traffic statistics including user-reported spam rate and bulk-vs-personal volume splits
Pull SPF, DKIM, and DMARC authentication success rates for outbound mail to Gmail recipients
Track domain and IP reputation classifications (high, medium, low, bad) over time
Surface delivery error breakdowns to diagnose why messages are bouncing or being filtered
Use Cases
Patterns agents use Gmail Postmaster Tools API for, with concrete tasks.
★ Deliverability Monitoring Dashboard
Email operations teams use the Gmail Postmaster Tools API to power internal deliverability dashboards that track spam rate, domain reputation, and authentication pass rates across all verified sending domains. The API returns per-day traffic statistics so dashboards can plot trends, alert on regressions, and correlate reputation drops with content or volume changes. This replaces manual UI checks across multiple domains and lets teams catch deliverability problems before they trigger throttling.
List all domains registered in Postmaster Tools, then for each domain fetch the last 7 days of traffic stats and flag any day where userReportedSpamRatio exceeds 0.003.
Authentication Compliance Audits
Compliance and security teams pull SPF, DKIM, and DMARC pass-rate data from the Postmaster Tools API to verify that outbound email from each business domain is correctly authenticated. The traffic stats endpoint reports the percentage of mail that passed each authentication check, so teams can spot misconfigured subdomains, unauthorised senders, or expired DKIM keys. Integration with a ticketing system lets failed-auth percentages over a threshold open an investigation automatically.
For domain marketing.example.com, fetch traffic stats for the last 30 days and compute the average DKIM and SPF success ratios; alert if either drops below 0.95.
AI Agent Deliverability Triage
An AI agent surfaces Gmail deliverability problems to email teams by pulling Postmaster Tools traffic stats through Jentic. When a CRM or marketing platform reports a campaign underperformance, the agent fetches the relevant domain's spam rate, reputation, and delivery errors for the campaign window and produces a plain-language diagnosis. Agents call the API with a scoped credential issued by Jentic so raw OAuth tokens never enter the agent context.
Given a campaign that ran on 2026-06-01 from sender marketing.example.com, fetch that day's traffic stats from Postmaster Tools and summarise whether spam rate, IP reputation, or authentication was the most likely cause of underperformance.
Key Endpoints
3 endpoints — the gmail postmaster tools api gives high-volume senders programmatic access to deliverability metrics that were previously only viewable in the postmaster tools ui.
METHOD
PATH
DESCRIPTION
GET
/v1/domains
List verified domains in the postmaster account
GET
/v1/{+name}
Get registration and verification details for a specific domain
GET
/v1/{+parent}/trafficStats
List daily traffic statistics for a domain
GET
/v1/domains
List verified domains in the postmaster account
GET
/v1/{+name}
Get registration and verification details for a specific domain
GET
/v1/{+parent}/trafficStats
List daily traffic statistics for a domain
Why Jentic?
Three things that make agents converge on Jentic-routed access.
Credential isolation
Google OAuth refresh tokens for Postmaster Tools are stored encrypted in the Jentic vault. Agents receive a short-lived access token scoped to postmaster.readonly at execution time so raw refresh tokens never enter the agent context.
Intent-based discovery
Agents search by intent (e.g. 'get gmail spam rate') and Jentic returns the matching trafficStats operation with its parameter schema, so the agent calls the right path without reading Google's discovery doc.
Time to first call
Direct integration with the Postmaster Tools API: 1-2 days for OAuth client setup, consent screen, and refresh token handling. Through Jentic: under 30 minutes — search, load, execute.
Related APIs
Alternatives and complements available in the Jentic catalogue.
FAQs
Specific to using Gmail Postmaster Tools API through Jentic.
What authentication does the Gmail Postmaster Tools API use?
The API uses Google OAuth 2.0 with the postmaster.readonly scope. Through Jentic, the OAuth token is held in the Jentic credential vault and exchanged for a scoped access token at execution time, so raw tokens never reach the agent context.
Can I retrieve historical spam rates with the Gmail Postmaster Tools API?
Yes. Call GET /v1/{+parent}/trafficStats on a verified domain to list daily traffic statistics, each of which includes userReportedSpamRatio and inboundEncryptionRatio. Google retains stats for a rolling window, so backfill beyond that window is not available.
What are the rate limits for the Gmail Postmaster Tools API?
Google enforces a default per-project quota for the Postmaster Tools API (currently 1,200 queries per minute per project). Quotas are managed in the Google Cloud Console and can be increased on request.
How do I pull yesterday's traffic stats through Jentic?
Search Jentic with 'get gmail postmaster traffic stats', load the listTrafficStats operation under /v1/{+parent}/trafficStats, then execute it with the parent set to domains/{your-domain}. Jentic returns the daily stats array including spam rate, reputation buckets, and authentication ratios.
Can I add new domains via the Gmail Postmaster Tools API?
No. Domain registration and DNS verification must be completed in the Postmaster Tools web UI before the API will return data for them. The API exposes only read endpoints for listing and reading domains and their stats.
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