blacklist: add domain reputation check via checker-blacklist

Integrates the checker-blacklist module behind a new POST /blacklist/domain
endpoint that aggregates reputation/blocklist sources for a given domain,
plus a SvelteKit UI under /blacklist/domain mirroring the existing IP
blacklist flow. Per-source credentials (VirusTotal, Safe Browsing) are
exposed as CLI flags; free sources run unconditionally.

Closes: #96

api/openapi.yaml

@@ -363,6 +363,12 @@ components:
       $ref: './schemas.yaml#/components/schemas/BlacklistCheckRequest'
     BlacklistCheckResponse:
       $ref: './schemas.yaml#/components/schemas/BlacklistCheckResponse'
+    DomainBlacklistResult:
+      $ref: './schemas.yaml#/components/schemas/DomainBlacklistResult'
+    DomainBlacklistSourceResult:
+      $ref: './schemas.yaml#/components/schemas/DomainBlacklistSourceResult'
+    DomainBlacklistEvidence:
+      $ref: './schemas.yaml#/components/schemas/DomainBlacklistEvidence'
     TestSummary:
       $ref: './schemas.yaml#/components/schemas/TestSummary'
     TestListResponse:

api/schemas.yaml

@@ -1217,6 +1217,9 @@ components:
           example: "A"
         dns_results:
           $ref: '#/components/schemas/DNSResults'
+        blacklist:
+          $ref: '#/components/schemas/DomainBlacklistResult'
+          description: Domain reputation/blacklist aggregation (omitted when the check could not be run)
 
     BlacklistCheckRequest:
       type: object
@@ -1268,6 +1271,103 @@ components:
             $ref: '#/components/schemas/BlacklistCheck'
           description: List of DNS whitelist check results (informational only)
 
+    DomainBlacklistResult:
+      type: object
+      required:
+        - registered_domain
+        - collected_at
+        - results
+      properties:
+        registered_domain:
+          type: string
+          description: eTLD+1 of the input domain
+          example: "example.com"
+        collected_at:
+          type: string
+          format: date-time
+          description: When the aggregation finished
+        score:
+          type: integer
+          minimum: 0
+          maximum: 100
+          description: Reputation score (0-100, higher is better). Omitted when the verdict is inconclusive (no usable source).
+          example: 100
+        grade:
+          type: string
+          enum: [A+, A, B, C, D, E, F]
+          description: Letter grade derived from the score. Omitted when the verdict is inconclusive.
+          example: "A+"
+        results:
+          type: array
+          items:
+            $ref: '#/components/schemas/DomainBlacklistSourceResult'
+          description: One entry per registered source (disabled sources included with enabled=false)
+
+    DomainBlacklistSourceResult:
+      type: object
+      required:
+        - source_id
+        - source_name
+        - enabled
+        - listed
+      properties:
+        source_id:
+          type: string
+          example: "quad9"
+        source_name:
+          type: string
+          example: "Quad9"
+        subject:
+          type: string
+          description: Per-zone identifier (DNSBL zones only)
+        enabled:
+          type: boolean
+          description: False when the source is disabled or missing credentials
+        listed:
+          type: boolean
+          description: Verdict from the source's Evaluate (false when disabled or errored)
+        blocked_query:
+          type: boolean
+          description: Resolver returned a block response (not a real listing)
+        severity:
+          type: string
+          description: Severity attached to the verdict (crit, warn, info, ok, or empty)
+        reasons:
+          type: array
+          items: { type: string }
+        evidence:
+          type: array
+          items:
+            $ref: '#/components/schemas/DomainBlacklistEvidence'
+        lookup_url:
+          type: string
+        removal_url:
+          type: string
+        reference:
+          type: string
+        error:
+          type: string
+        details:
+          type: object
+          additionalProperties: true
+          description: Source-specific structured data (free-form)
+
+    DomainBlacklistEvidence:
+      type: object
+      required:
+        - label
+        - value
+      properties:
+        label:
+          type: string
+        value:
+          type: string
+        status:
+          type: string
+        extra:
+          type: object
+          additionalProperties: { type: string }
+
     TestSummary:
       type: object
       required:

go.mod

@@ -3,6 +3,8 @@ module git.happydns.org/happyDeliver
 go 1.25.0
 
 require (
+	git.happydns.org/checker-blacklist v0.4.0
+	git.happydns.org/checker-sdk-go v1.9.0
 	github.com/JGLTechnologies/gin-rate-limit v1.5.8
 	github.com/emersion/go-smtp v0.24.0
 	github.com/getkin/kin-openapi v0.138.0

go.sum

@@ -1,3 +1,7 @@
+git.happydns.org/checker-blacklist v0.4.0 h1:mTOWz2tcMXGU2WFVM9VLxnSJ7mFXL2Lhq5NBq+lUU7g=
+git.happydns.org/checker-blacklist v0.4.0/go.mod h1:huOwQWfAA+Wo+WbUbtyRIS/Y0eA+C3YrguGuJL+3qEE=
+git.happydns.org/checker-sdk-go v1.9.0 h1:orBRymir+p6PMHVa4focryPKhTVWT7JAv6u9Ido5KF0=
+git.happydns.org/checker-sdk-go v1.9.0/go.mod h1:aNAcfYFfbhvH9kJhE0Njp5GX0dQbxdRB0rJ0KvSC5nI=
 github.com/JGLTechnologies/gin-rate-limit v1.5.8 h1:KiaHIEbpYxHpDvjhpjIif8fnVmjdw/afCMdGoN1AsB0=
 github.com/JGLTechnologies/gin-rate-limit v1.5.8/go.mod h1:t9eLOUxikPI0TzKy0VYRbZJr7hBP2Qg9E3JigoxF70g=
 github.com/RaveNoX/go-jsoncommentstrip v1.0.0/go.mod h1:78ihd09MekBnJnxpICcwzCMzGrKSKYe4AqU6PDYYpjk=

internal/api/handlers.go

@@ -22,6 +22,7 @@
 package api
 
 import (
+	"context"
 	"fmt"
 	"net/http"
 	"time"
@@ -30,8 +31,10 @@ import (
 	"github.com/google/uuid"
 	openapi_types "github.com/oapi-codegen/runtime/types"
 
+	sdk "git.happydns.org/checker-sdk-go/checker"
 	"git.happydns.org/happyDeliver/internal/config"
 	"git.happydns.org/happyDeliver/internal/model"
+	"git.happydns.org/happyDeliver/internal/reputation"
 	"git.happydns.org/happyDeliver/internal/storage"
 	"git.happydns.org/happyDeliver/internal/utils"
 	"git.happydns.org/happyDeliver/internal/version"
@@ -47,19 +50,21 @@ type EmailAnalyzer interface {
 
 // APIHandler implements the ServerInterface for handling API requests
 type APIHandler struct {
-	storage   storage.Storage
+	storage           storage.Storage
-	config    *config.Config
+	config            *config.Config
-	analyzer  EmailAnalyzer
+	analyzer          EmailAnalyzer
-	startTime time.Time
+	blacklistProvider sdk.ObservationProvider
+	startTime         time.Time
 }
 
 // NewAPIHandler creates a new API handler
-func NewAPIHandler(store storage.Storage, cfg *config.Config, analyzer EmailAnalyzer) *APIHandler {
+func NewAPIHandler(store storage.Storage, cfg *config.Config, analyzer EmailAnalyzer, blacklistProvider sdk.ObservationProvider) *APIHandler {
 	return &APIHandler{
-		storage:   store,
+		storage:           store,
-		config:    cfg,
+		config:            cfg,
-		analyzer:  analyzer,
+		analyzer:          analyzer,
-		startTime: time.Now(),
+		blacklistProvider: blacklistProvider,
+		startTime:         time.Now(),
 	}
 }
 
@@ -339,6 +344,7 @@ func (h *APIHandler) TestDomain(c *gin.Context) {
 		Score:      score,
 		Grade:      responseGrade,
 		DnsResults: *dnsResults,
+		Blacklist:  h.runDomainBlacklist(c.Request.Context(), request.Domain),
 	}
 
 	c.JSON(http.StatusOK, response)
@@ -383,6 +389,32 @@ func (h *APIHandler) CheckBlacklist(c *gin.Context) {
 	c.JSON(http.StatusOK, response)
 }
 
+// runDomainBlacklist runs the checker-blacklist aggregation against a domain.
+// It returns nil (and logs nothing fatal) when the check cannot be run, so the
+// surrounding domain analysis still succeeds.
+func (h *APIHandler) runDomainBlacklist(ctx context.Context, domain string) *model.DomainBlacklistResult {
+	opts := h.config.Analysis.Blacklist.AsCheckerOptions()
+	// "domain_name" is the option key the checker-blacklist provider reads
+	// (see checker/collect.go in the checker-blacklist module).
+	opts["domain_name"] = domain
+
+	// Cap the aggregation: sources run concurrently, each with its own
+	// timeouts; this is the host-side ceiling.
+	timeout := h.config.Analysis.HTTPTimeout
+	if timeout <= 0 {
+		timeout = 30 * time.Second
+	}
+	ctx, cancel := context.WithTimeout(ctx, timeout)
+	defer cancel()
+
+	raw, err := h.blacklistProvider.Collect(ctx, opts)
+	if err != nil {
+		return nil
+	}
+
+	return reputation.FromObservation(raw)
+}
+
 // ListTests returns a paginated list of test summaries
 // (GET /tests)
 func (h *APIHandler) ListTests(c *gin.Context, params ListTestsParams) {

internal/app/server.go

@@ -30,6 +30,7 @@ import (
 	ratelimit "github.com/JGLTechnologies/gin-rate-limit"
 	"github.com/gin-gonic/gin"
 
+	blacklist "git.happydns.org/checker-blacklist/checker"
 	"git.happydns.org/happyDeliver/internal/api"
 	"git.happydns.org/happyDeliver/internal/config"
 	"git.happydns.org/happyDeliver/internal/lmtp"
@@ -70,7 +71,7 @@ func RunServer(cfg *config.Config) error {
 	analyzerAdapter := analyzer.NewAPIAdapter(cfg)
 
 	// Create API handler
-	handler := api.NewAPIHandler(store, cfg, analyzerAdapter)
+	handler := api.NewAPIHandler(store, cfg, analyzerAdapter, blacklist.Provider())
 
 	// Set up Gin router
 	if os.Getenv("GIN_MODE") == "" {

internal/config/blacklist.go

@@ -0,0 +1,40 @@
+// This file is part of the happyDeliver (R) project.
+// Copyright (c) 2025 happyDomain
+// Authors: Pierre-Olivier Mercier, et al.
+//
+// This program is offered under a commercial and under the AGPL license.
+// For commercial licensing, contact us at <contact@happydomain.org>.
+//
+// For AGPL licensing:
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+package config
+
+import (
+	sdk "git.happydns.org/checker-sdk-go/checker"
+)
+
+// AsCheckerOptions returns the map that checker-blacklist sources read
+// via stringOpt(). Empty values are omitted so sources that require a
+// credential stay disabled rather than failing with an empty key.
+func (b BlacklistConfig) AsCheckerOptions() sdk.CheckerOptions {
+	opts := sdk.CheckerOptions{}
+	if b.VirusTotalAPIKey != "" {
+		opts["virustotal_api_key"] = b.VirusTotalAPIKey
+	}
+	if b.SafeBrowsingAPIKey != "" {
+		opts["safebrowsing_api_key"] = b.SafeBrowsingAPIKey
+	}
+	return opts
+}

internal/config/cli.go

@@ -40,6 +40,8 @@ func declareFlags(o *Config) {
 	flag.Var(&StringArray{&o.Analysis.RBLs}, "rbl", "Append a RBL (use this option multiple time to append multiple RBLs)")
 	flag.BoolVar(&o.Analysis.CheckAllIPs, "check-all-ips", o.Analysis.CheckAllIPs, "Check all IPs found in email headers against RBLs (not just the first one)")
 	flag.StringVar(&o.Analysis.RspamdAPIURL, "rspamd-api-url", o.Analysis.RspamdAPIURL, "rspamd API URL for symbol descriptions (default: use embedded list)")
+	flag.StringVar(&o.Analysis.Blacklist.VirusTotalAPIKey, "blacklist-virustotal-api-key", o.Analysis.Blacklist.VirusTotalAPIKey, "VirusTotal v3 API key for the domain blacklist checker")
+	flag.StringVar(&o.Analysis.Blacklist.SafeBrowsingAPIKey, "blacklist-safebrowsing-api-key", o.Analysis.Blacklist.SafeBrowsingAPIKey, "Google Safe Browsing API key for the domain blacklist checker")
 	flag.DurationVar(&o.ReportRetention, "report-retention", o.ReportRetention, "How long to keep reports (e.g., 720h, 30d). 0 = keep forever")
 	flag.UintVar(&o.RateLimit, "rate-limit", o.RateLimit, "API rate limit (requests per second per IP)")
 	flag.Var(&URL{&o.SurveyURL}, "survey-url", "URL for user feedback survey")

internal/config/config.go

@@ -75,6 +75,18 @@ type AnalysisConfig struct {
 	DNSWLs       []string
 	CheckAllIPs  bool   // Check all IPs found in headers, not just the first one
 	RspamdAPIURL string // rspamd API URL for fetching symbol descriptions (empty = use embedded list)
+	Blacklist    BlacklistConfig
+}
+
+// BlacklistConfig holds per-source credentials/options for the
+// domain-oriented checker-blacklist provider. Keys must match the
+// option IDs declared by each source in the checker-blacklist module
+// (see checker/virustotal.go, checker/safebrowsing.go, …). Free sources
+// (Quad9, OISD, URLhaus, OpenPhish, Disconnect, Botvrij, …) need no
+// configuration.
+type BlacklistConfig struct {
+	VirusTotalAPIKey   string
+	SafeBrowsingAPIKey string
 }
 
 // DefaultConfig returns a configuration with sensible defaults

web/src/lib/components/DomainBlacklistCard.svelte

@@ -0,0 +1,260 @@
+<script lang="ts">
+    import type { DomainBlacklistSourceResult } from "$lib/api/types.gen";
+    import { theme } from "$lib/stores/theme";
+
+    interface Props {
+        results: DomainBlacklistSourceResult[];
+    }
+
+    let { results }: Props = $props();
+
+    // Paid sources that show a "configure API key" hint when disabled.
+    const paidSourceIds = new Set(["virustotal", "safebrowsing"]);
+
+    type Bucket = "listed" | "errored" | "clean" | "disabled";
+
+    function classify(r: DomainBlacklistSourceResult): Bucket {
+        if (!r.enabled) return "disabled";
+        if (r.error) return "errored";
+        if (r.listed) return "listed";
+        return "clean";
+    }
+
+    function severityRank(sev: string | undefined): number {
+        switch (sev) {
+            case "crit":
+                return 0;
+            case "warn":
+                return 1;
+            case "info":
+                return 2;
+            default:
+                return 3;
+        }
+    }
+
+    function bucketRank(b: Bucket): number {
+        switch (b) {
+            case "listed":
+                return 0;
+            case "errored":
+                return 1;
+            case "clean":
+                return 2;
+            case "disabled":
+                return 3;
+        }
+    }
+
+    let sorted = $derived(
+        [...results].sort((a, b) => {
+            const ba = classify(a);
+            const bb = classify(b);
+            if (ba !== bb) return bucketRank(ba) - bucketRank(bb);
+            if (ba === "listed") {
+                const r = severityRank(a.severity) - severityRank(b.severity);
+                if (r !== 0) return r;
+            }
+            return a.source_name.localeCompare(b.source_name);
+        }),
+    );
+
+    function statusLabel(r: DomainBlacklistSourceResult): string {
+        if (!r.enabled) return "Disabled";
+        if (r.error) return "Error";
+        if (r.listed) {
+            if (r.severity && r.severity !== "ok") {
+                return `Listed (${r.severity})`;
+            }
+            return "Listed";
+        }
+        return "Clean";
+    }
+
+    function statusBadgeClass(r: DomainBlacklistSourceResult): string {
+        if (!r.enabled) return "bg-secondary";
+        if (r.error) return "bg-dark";
+        if (r.listed) {
+            switch (r.severity) {
+                case "crit":
+                    return "bg-danger";
+                case "warn":
+                    return "bg-warning text-dark";
+                case "info":
+                    return "bg-info text-dark";
+                default:
+                    return "bg-danger";
+            }
+        }
+        return "bg-success";
+    }
+
+    let openRows = $state(new Set<string>());
+
+    function rowKey(r: DomainBlacklistSourceResult): string {
+        return `${r.source_id}::${r.subject ?? ""}`;
+    }
+
+    function toggle(key: string) {
+        const next = new Set(openRows);
+        if (next.has(key)) {
+            next.delete(key);
+        } else {
+            next.add(key);
+        }
+        openRows = next;
+    }
+
+    function hasDetails(r: DomainBlacklistSourceResult): boolean {
+        return (r.reasons?.length ?? 0) > 1 || (r.evidence?.length ?? 0) > 0;
+    }
+
+    function firstReason(r: DomainBlacklistSourceResult): string {
+        if (r.error) return r.error;
+        if (r.reasons && r.reasons.length > 0) return r.reasons[0];
+        if (!r.enabled && paidSourceIds.has(r.source_id)) {
+            return "API key not configured by the operator";
+        }
+        if (!r.enabled) return "Source disabled";
+        return "—";
+    }
+</script>
+
+<div class="card shadow-sm mt-4" id="domain-blacklist-details">
+    <div class="card-header" class:bg-white={$theme === "light"} class:bg-dark={$theme !== "light"}>
+        <h4 class="mb-0">
+            <i class="bi bi-shield-shaded me-2"></i>
+            Source Verdicts
+        </h4>
+    </div>
+    <div class="card-body">
+        <div class="table-responsive">
+            <table class="table table-sm table-striped table-hover align-middle mb-0">
+                <thead>
+                    <tr>
+                        <th scope="col" class="text-nowrap">Status</th>
+                        <th scope="col">Source</th>
+                        <th scope="col">Detail</th>
+                        <th scope="col" class="text-end text-nowrap">Links</th>
+                    </tr>
+                </thead>
+                <tbody>
+                    {#each sorted as r (rowKey(r))}
+                        {@const key = rowKey(r)}
+                        {@const open = openRows.has(key)}
+                        {@const expandable = hasDetails(r)}
+                        <tr class:text-muted={!r.enabled}>
+                            <td class="text-nowrap">
+                                <span class="badge {statusBadgeClass(r)}">{statusLabel(r)}</span>
+                            </td>
+                            <td>
+                                <div class="fw-semibold">{r.source_name}</div>
+                                <small class="text-muted">
+                                    <code>{r.source_id}</code>
+                                    {#if r.subject}
+                                        · <code>{r.subject}</code>
+                                    {/if}
+                                </small>
+                            </td>
+                            <td>
+                                <span class="detail-text">{firstReason(r)}</span>
+                                {#if expandable}
+                                    <button
+                                        type="button"
+                                        class="btn btn-link btn-sm p-0 ms-1 align-baseline"
+                                        onclick={() => toggle(key)}
+                                        aria-expanded={open}
+                                    >
+                                        {open ? "Hide details" : "Show details"}
+                                    </button>
+                                {/if}
+                            </td>
+                            <td class="text-end text-nowrap">
+                                {#if r.lookup_url}
+                                    <a
+                                        href={r.lookup_url}
+                                        target="_blank"
+                                        rel="noopener noreferrer"
+                                        class="btn btn-sm btn-outline-secondary"
+                                        title="Open lookup page"
+                                        aria-label="Open lookup page"
+                                    >
+                                        <i class="bi bi-box-arrow-up-right"></i>
+                                    </a>
+                                {/if}
+                            </td>
+                        </tr>
+                        {#if expandable && open}
+                            <tr class="detail-row">
+                                <td></td>
+                                <td colspan="3">
+                                    {#if r.reasons && r.reasons.length > 0}
+                                        <ul class="small mb-2">
+                                            {#each r.reasons as reason}
+                                                <li>{reason}</li>
+                                            {/each}
+                                        </ul>
+                                    {/if}
+                                    {#if r.evidence && r.evidence.length > 0}
+                                        <table
+                                            class="table table-sm table-bordered mb-0 evidence-table"
+                                        >
+                                            <thead>
+                                                <tr>
+                                                    <th scope="col">Label</th>
+                                                    <th scope="col">Value</th>
+                                                    <th scope="col">Status</th>
+                                                </tr>
+                                            </thead>
+                                            <tbody>
+                                                {#each r.evidence as ev}
+                                                    <tr>
+                                                        <td class="text-nowrap">{ev.label}</td>
+                                                        <td>
+                                                            <code class="small">{ev.value}</code>
+                                                        </td>
+                                                        <td class="text-nowrap">
+                                                            {#if ev.status}
+                                                                <span
+                                                                    class="badge bg-light text-dark"
+                                                                    >{ev.status}</span
+                                                                >
+                                                            {:else}
+                                                                <span class="text-muted">—</span>
+                                                            {/if}
+                                                        </td>
+                                                    </tr>
+                                                {/each}
+                                            </tbody>
+                                        </table>
+                                    {/if}
+                                    {#if r.reference}
+                                        <p class="small text-muted mt-2 mb-0">
+                                            Reference: {r.reference}
+                                        </p>
+                                    {/if}
+                                </td>
+                            </tr>
+                        {/if}
+                    {/each}
+                </tbody>
+            </table>
+        </div>
+    </div>
+</div>
+
+<style>
+    .detail-text {
+        display: inline-block;
+        max-width: 100%;
+        overflow-wrap: anywhere;
+    }
+
+    .detail-row td {
+        background-color: rgba(0, 0, 0, 0.025);
+    }
+
+    .evidence-table code {
+        word-break: break-all;
+    }
+</style>

web/src/lib/components/index.ts

@@ -6,6 +6,7 @@ export { default as ContentAnalysisCard } from "./ContentAnalysisCard.svelte";
 export { default as DkimRecordsDisplay } from "./DkimRecordsDisplay.svelte";
 export { default as DmarcRecordDisplay } from "./DmarcRecordDisplay.svelte";
 export { default as DnsRecordsCard } from "./DnsRecordsCard.svelte";
+export { default as DomainBlacklistCard } from "./DomainBlacklistCard.svelte";
 export { default as EmailAddressDisplay } from "./EmailAddressDisplay.svelte";
 export { default as EmailPathCard } from "./EmailPathCard.svelte";
 export { default as ErrorDisplay } from "./ErrorDisplay.svelte";

web/src/routes/blacklist/+page.svelte

@@ -161,6 +161,10 @@
                     <i class="bi bi-envelope-plus me-1"></i>
                     Send Test Email
                 </a>
+                <a href="/domain" class="btn btn-sm btn-outline-primary ms-1">
+                    <i class="bi bi-shield-shaded me-1"></i>
+                    Check a Domain
+                </a>
             </div>
         </div>
     </div>

web/src/routes/domain/[domain]/+page.svelte

@@ -4,7 +4,7 @@
 
     import { testDomain } from "$lib/api";
     import type { DomainTestResponse } from "$lib/api/types.gen";
-    import { DnsRecordsCard, GradeDisplay, TinySurvey } from "$lib/components";
+    import { DnsRecordsCard, DomainBlacklistCard, GradeDisplay, TinySurvey } from "$lib/components";
     import { theme } from "$lib/stores/theme";
 
     let domain = $derived(page.params.domain);
@@ -12,6 +12,44 @@
     let error = $state<string | null>(null);
     let result = $state<DomainTestResponse | null>(null);
 
+    let blacklist = $derived(result?.blacklist ?? null);
+
+    let blacklistSummary = $derived.by(() => {
+        if (!blacklist) return null;
+        const enabled = blacklist.results.filter((r) => r.enabled);
+        const disabled = blacklist.results.length - enabled.length;
+        const errored = enabled.filter((r) => r.error).length;
+        const listed = enabled.filter((r) => r.listed);
+        const critical = listed.filter((r) => r.severity === "crit").length;
+        return {
+            total: blacklist.results.length,
+            enabled: enabled.length,
+            disabled,
+            errored,
+            listed: listed.length,
+            critical,
+        };
+    });
+
+    type Verdict = "danger" | "warn" | "inconclusive" | "ok";
+
+    let blacklistVerdict = $derived.by<Verdict | null>(() => {
+        const s = blacklistSummary;
+        if (!s) return null;
+        if (s.critical > 0) return "danger";
+        if (s.listed > 0) return "warn";
+        if (s.enabled > 0 && s.errored === s.enabled) return "inconclusive";
+        return "ok";
+    });
+
+    function formatCollectedAt(iso: string): string {
+        try {
+            return new Date(iso).toLocaleString();
+        } catch {
+            return iso;
+        }
+    }
+
     async function analyzeDomain() {
         loading = true;
         error = null;
@@ -74,7 +112,9 @@
                             <span class="visually-hidden">Loading...</span>
                         </div>
                         <h3 class="h5">Analyzing {domain}...</h3>
-                        <p class="text-muted mb-0">Checking DNS records and configuration</p>
+                        <p class="text-muted mb-0">
+                            Checking DNS records, configuration and domain reputation
+                        </p>
                     </div>
                 </div>
             {:else if error}
@@ -116,14 +156,31 @@
                                         <p class="text-muted mb-0">Domain Configuration Score</p>
                                     {/if}
                                 </div>
-                                <div class="offset-md-3 col-md-3 text-center">
+                                <div class="col-md-6">
                                     <div
-                                        class="p-2 rounded text-center summary-card"
+                                        class="d-flex justify-content-md-end justify-content-center gap-3"
-                                        class:bg-light={$theme === "light"}
-                                        class:bg-secondary={$theme !== "light"}
                                     >
-                                        <GradeDisplay score={result.score} grade={result.grade} />
+                                        <div
-                                        <small class="text-muted d-block">DNS</small>
+                                            class="p-2 rounded text-center summary-card"
+                                            class:bg-light={$theme === "light"}
+                                            class:bg-secondary={$theme !== "light"}
+                                        >
+                                            <GradeDisplay
+                                                score={result.score}
+                                                grade={result.grade}
+                                            />
+                                            <small class="text-muted d-block">DNS</small>
+                                        </div>
+                                        {#if blacklist}
+                                            <div
+                                                class="p-2 rounded text-center summary-card"
+                                                class:bg-light={$theme === "light"}
+                                                class:bg-secondary={$theme !== "light"}
+                                            >
+                                                <GradeDisplay grade={blacklist.grade ?? "?"} />
+                                                <small class="text-muted d-block">Reputation</small>
+                                            </div>
+                                        {/if}
                                     </div>
                                 </div>
                             </div>
@@ -144,6 +201,119 @@
                         domainOnly={true}
                     />
 
+                    <!-- Domain Reputation / Blacklist -->
+                    {#if blacklist && blacklistSummary}
+                        <div class="card shadow-sm mt-4">
+                            <div class="card-body p-4">
+                                <div class="row align-items-center">
+                                    <div class="col-md-7 text-center text-md-start mb-3 mb-md-0">
+                                        <h3 class="h5 mb-2">
+                                            <i class="bi bi-shield-shaded me-2"></i>
+                                            Domain Reputation
+                                        </h3>
+                                        {#if blacklist.registered_domain && blacklist.registered_domain !== result.domain}
+                                            <p class="text-muted small mb-2">
+                                                Registered domain:
+                                                <code>{blacklist.registered_domain}</code>
+                                            </p>
+                                        {/if}
+
+                                        {#if blacklistVerdict === "danger"}
+                                            <div class="alert alert-danger mb-0 d-inline-block">
+                                                <i class="bi bi-exclamation-octagon me-2"></i>
+                                                <strong
+                                                    >Listed on {blacklistSummary.critical} high-severity
+                                                    source{blacklistSummary.critical > 1
+                                                        ? "s"
+                                                        : ""}</strong
+                                                >
+                                                <p class="mb-0 mt-1 small">
+                                                    This domain is reported by sources flagged
+                                                    <em>critical</em>. Take action to delist.
+                                                </p>
+                                            </div>
+                                        {:else if blacklistVerdict === "warn"}
+                                            <div class="alert alert-warning mb-0 d-inline-block">
+                                                <i class="bi bi-exclamation-triangle me-2"></i>
+                                                <strong
+                                                    >Listed on {blacklistSummary.listed} source{blacklistSummary.listed >
+                                                    1
+                                                        ? "s"
+                                                        : ""}</strong
+                                                >
+                                                <p class="mb-0 mt-1 small">
+                                                    Listed without critical severity — review the
+                                                    source verdicts below.
+                                                </p>
+                                            </div>
+                                        {:else if blacklistVerdict === "inconclusive"}
+                                            <div class="alert alert-warning mb-0 d-inline-block">
+                                                <i class="bi bi-question-octagon me-2"></i>
+                                                <strong>Inconclusive</strong>
+                                                <p class="mb-0 mt-1 small">
+                                                    All enabled sources returned errors. Try again
+                                                    later.
+                                                </p>
+                                            </div>
+                                        {:else}
+                                            <div class="alert alert-success mb-0 d-inline-block">
+                                                <i class="bi bi-check-circle me-2"></i>
+                                                <strong>No source reports this domain</strong>
+                                                <p class="mb-0 mt-1 small">
+                                                    Clean across all {blacklistSummary.enabled} enabled
+                                                    source{blacklistSummary.enabled > 1 ? "s" : ""}.
+                                                </p>
+                                            </div>
+                                        {/if}
+                                    </div>
+                                    <div class="col-md-5 text-center">
+                                        <div
+                                            class="p-3 rounded summary-card"
+                                            class:bg-light={$theme === "light"}
+                                            class:bg-secondary={$theme !== "light"}
+                                        >
+                                            <div class="d-flex justify-content-around mb-2">
+                                                <div>
+                                                    <div class="h4 mb-0">
+                                                        {blacklistSummary.enabled}
+                                                    </div>
+                                                    <small class="text-muted">Enabled</small>
+                                                </div>
+                                                <div>
+                                                    <div class="h4 mb-0 text-danger">
+                                                        {blacklistSummary.listed}
+                                                    </div>
+                                                    <small class="text-muted">Listed</small>
+                                                </div>
+                                                <div>
+                                                    <div class="h4 mb-0 text-secondary">
+                                                        {blacklistSummary.disabled}
+                                                    </div>
+                                                    <small class="text-muted">Disabled</small>
+                                                </div>
+                                            </div>
+                                            {#if blacklistSummary.errored > 0}
+                                                <small class="text-muted d-block">
+                                                    {blacklistSummary.errored} source{blacklistSummary.errored >
+                                                    1
+                                                        ? "s"
+                                                        : ""} errored
+                                                </small>
+                                            {/if}
+                                            <small class="text-muted d-block">
+                                                Collected {formatCollectedAt(
+                                                    blacklist.collected_at,
+                                                )}
+                                            </small>
+                                        </div>
+                                    </div>
+                                </div>
+                            </div>
+                        </div>
+
+                        <DomainBlacklistCard results={blacklist.results} />
+                    {/if}
+
                     <!-- Next Steps -->
                     <div class="card shadow-sm border-primary mt-4">
                         <div class="card-body">
@@ -152,9 +322,9 @@
                                 Want Complete Email Analysis?
                             </h3>
                             <p class="mb-3">
-                                This domain-only test checks DNS configuration. For comprehensive
+                                This domain test checks DNS configuration and domain reputation. For
-                                deliverability testing including DKIM verification, content
+                                comprehensive deliverability testing including DKIM verification,
-                                analysis, spam scoring, and blacklist checks:
+                                content analysis, spam scoring, and sending-IP blacklist checks:
                             </p>
                             <a href="/" class="btn btn-primary">
                                 <i class="bi bi-envelope-plus me-2"></i>