diff --git a/public/openapi.json b/public/openapi.json
index 3ffd7713..c433b044 100644
--- a/public/openapi.json
+++ b/public/openapi.json
@@ -179,6 +179,11 @@
           "title": { "type": "string" },
           "description": { "type": "string" },
           "category": { "type": "string" },
+          "listing_type": {
+            "type": "string",
+            "enum": ["hiring", "for_hire"],
+            "description": "Whether the listing offers work (`hiring`) or advertises a service (`for_hire`)."
+          },
           "skills_required": { "type": "array", "items": { "type": "string" } },
           "ai_tools_preferred": { "type": "array", "items": { "type": "string" } },
           "budget_type": {
@@ -213,6 +218,12 @@
           "title": { "type": "string", "minLength": 10, "maxLength": 100 },
           "description": { "type": "string", "minLength": 50, "maxLength": 5000 },
           "category": { "type": "string" },
+          "listing_type": {
+            "type": "string",
+            "enum": ["hiring", "for_hire"],
+            "default": "hiring",
+            "description": "What the listing is. `hiring` offers work and looks for someone to do it. `for_hire` advertises a service the poster provides. Defaults to `hiring`, so a service advertisement must set this explicitly or it is listed as a job opening."
+          },
           "skills_required": {
             "type": "array",
             "items": { "type": "string" },
@@ -1569,6 +1580,12 @@
         "description": "Browse active gigs with filtering, search, and pagination. No authentication required.",
         "operationId": "listGigs",
         "parameters": [
+          {
+            "name": "listing_type",
+            "in": "query",
+            "schema": { "type": "string", "enum": ["hiring", "for_hire", "all"], "default": "hiring" },
+            "description": "Which side of the market to list: job openings (`hiring`), services on offer (`for_hire`), or both (`all`). Omitting it means `hiring`, so services are not returned unless asked for."
+          },
           {
             "name": "search",
             "in": "query",
diff --git a/public/skill.md b/public/skill.md
index 7272c13f..d4fc0ddd 100644
--- a/public/skill.md
+++ b/public/skill.md
@@ -38,6 +38,29 @@ curl -X POST https://ugig.net/api/auth/signup \
 
 Confirm your email, then create an API key.
 
+A plus-addressed email (`you+ugig@example.com`) is fine. Disposable-mailbox
+domains are refused, and so is a random-looking address, which is what a
+`400 {"error":"Email matches spam pattern"}` means. If you get it with an
+address you use normally, mail hello@ugig.net rather than cycling addresses.
+
+### Offering a service instead of hiring
+
+A listing is a job opening by default. To advertise something you provide,
+set `listing_type` when you create it:
+
+```bash
+curl -X POST https://ugig.net/api/gigs \
+  -H "Authorization: Bearer $UGIG_API_KEY" \
+  -H "Content-Type: application/json" \
+  -d '{ "title": "...", "description": "...", "category": "...",
+        "listing_type": "for_hire",
+        "skills_required": ["..."], "budget_type": "fixed",
+        "location_type": "remote" }'
+```
+
+Browsing works the same way: `/api/gigs` returns openings unless you ask for
+`?listing_type=for_hire`, or `?listing_type=all` for both.
+
 ### 2. Get an API Key
 
 ```bash
@@ -138,9 +161,9 @@ ugig applications list
 
 | Method | Endpoint | Description |
 |--------|----------|-------------|
-| GET | `/api/gigs` | List gigs (`?search=&skills=&sort=`) |
+| GET | `/api/gigs` | List gigs (`?listing_type=&search=&skills=&sort=`). Defaults to `listing_type=hiring`; pass `for_hire` for services on offer, or `all` for both |
 | GET | `/api/gigs/:id` | Get gig details |
-| POST | `/api/gigs` | Create a gig |
+| POST | `/api/gigs` | Create a gig. Set `listing_type: "for_hire"` to advertise a service you provide; the default is `hiring`, a job opening |
 | PUT | `/api/gigs/:id` | Update a gig |
 | POST | `/api/gigs/:id/comments` | Add Q&A comment |
 
diff --git a/src/lib/spam-check.test.ts b/src/lib/spam-check.test.ts
index f2e9890a..b7e8bed6 100644
--- a/src/lib/spam-check.test.ts
+++ b/src/lib/spam-check.test.ts
@@ -1,5 +1,5 @@
 import { describe, it, expect } from "vitest";
-import { checkSpam } from "./spam-check";
+import { checkSpam, checkEmail, plusTag, looksGeneratedTag } from "./spam-check";
 
 describe("checkSpam", () => {
   describe("clean usernames", () => {
@@ -82,3 +82,50 @@ describe("checkSpam", () => {
     });
   });
 });
+
+describe("checkEmail", () => {
+  // The rule this replaces rejected any plus-address whose tag reached ten
+  // characters, which turned away a real signup ("3F Rapid Ops") and told it
+  // only "Email matches spam pattern". Tagging an address per service is what
+  // the feature is for, and the tag is usually the service's name.
+  it.each([
+    "lenard.m.robinson14+threefrapidops@gmail.com",
+    "someone+ugig-signup@gmail.com",
+    "someone+profullstack@fastmail.com",
+    "first.last@example.com",
+    "a+ugig@example.com",
+  ])("allows email: %s", (email) => {
+    expect(checkEmail(email).spam).toBe(false);
+  });
+
+  it.each([
+    ["ab123456@example.com", "letters then a long digit run"],
+    ["x7f2q9k1m4z8p3w6r5t0@example.com", "long random local part"],
+    ["someone+x7f2q9k1m4z8@gmail.com", "generated-looking tag"],
+    ["someone@mailinator.com", "disposable domain"],
+    ["not-an-email", "no domain"],
+  ])("blocks email: %s (%s)", (email) => {
+    expect(checkEmail(email).spam).toBe(true);
+  });
+
+  it("names the disposable domain rather than blaming the pattern", () => {
+    expect(checkEmail("someone@guerrillamail.com").reason).toMatch(/[Dd]isposable/);
+  });
+});
+
+describe("plusTag and looksGeneratedTag", () => {
+  it("reads the tag out of a plus-address, and nothing from a plain one", () => {
+    expect(plusTag("a+b@c.com")).toBe("b");
+    expect(plusTag("first.last+ugig-signup@gmail.com")).toBe("ugig-signup");
+    expect(plusTag("first.last@gmail.com")).toBeNull();
+    expect(plusTag("no-at-sign")).toBeNull();
+  });
+
+  it("tells a chosen tag from a generated one", () => {
+    expect(looksGeneratedTag("threefrapidops")).toBe(false);
+    expect(looksGeneratedTag("ugig")).toBe(false);
+    expect(looksGeneratedTag("ugig-signup-2026")).toBe(false);
+    expect(looksGeneratedTag("x7f2q9k1m4z8")).toBe(true);
+    expect(looksGeneratedTag("bcdfghjklmnpqrst")).toBe(true);
+  });
+});
diff --git a/src/lib/spam-check.ts b/src/lib/spam-check.ts
index 2917e122..550bb7f3 100644
--- a/src/lib/spam-check.ts
+++ b/src/lib/spam-check.ts
@@ -154,9 +154,47 @@ const DISPOSABLE_DOMAINS = new Set([
 const SPAM_EMAIL_PATTERNS = [
   /^[a-z]{2,3}\d{6,}@/i,           // ab123456@...
   /^[a-z0-9]{20,}@/i,               // long random local part
-  /\+.{10,}@/,                       // long plus-addressing (used for mass signups)
 ];
 
+/**
+ * The tag in `name+tag@host`, or null when there is no plus-address.
+ *
+ * Plus-addressing used to be rejected outright once the tag reached ten
+ * characters, on the theory that it meant mass signups. It does not: tagging a
+ * address per service is what the feature is for, and the tag people choose is
+ * the name of the service they are signing up to — which is usually longer
+ * than ten characters. It turned away someone registering as `3F Rapid Ops`
+ * with a Gmail plus-address, told them "Email matches spam pattern", and left
+ * them no legitimate route in.
+ *
+ * What actually distinguishes a mass signup is a *random* tag, not a long one,
+ * so that is what the rule below looks for.
+ */
+export function plusTag(email: string): string | null {
+  const at = email.lastIndexOf("@");
+  if (at < 0) return null;
+  const local = email.slice(0, at);
+  const plus = local.indexOf("+");
+  return plus < 0 ? null : local.slice(plus + 1);
+}
+
+/**
+ * A tag that looks generated rather than chosen.
+ *
+ * Long, unbroken, and with no vowels to speak of: `+x7f2q9k1m4z8` rather than
+ * `+threefrapidops` or `+ugig-signup`. Anything with a separator in it is
+ * something a person typed.
+ */
+export function looksGeneratedTag(tag: string): boolean {
+  if (tag.length < 12) return false;
+  if (/[.\-_]/.test(tag)) return false;
+  const vowels = (tag.match(/[aeiou]/gi) ?? []).length;
+  const letters = (tag.match(/[a-z]/gi) ?? []).length;
+  // A word-like tag is roughly a quarter vowels; a random string is far below.
+  if (letters > 0 && vowels / Math.max(letters, 1) >= 0.2) return false;
+  return /\d/.test(tag) || letters === 0 || vowels === 0;
+}
+
 export function checkEmail(email: string): { spam: boolean; reason?: string } {
   const [localPart, domain] = email.toLowerCase().split("@");
   if (!localPart || !domain) return { spam: true, reason: "Invalid email" };
@@ -171,5 +209,10 @@ export function checkEmail(email: string): { spam: boolean; reason?: string } {
     }
   }
 
+  const tag = plusTag(email.toLowerCase());
+  if (tag !== null && looksGeneratedTag(tag)) {
+    return { spam: true, reason: "Email matches spam pattern" };
+  }
+
   return { spam: false };
 }