Promo Seeker: Auto-find Promo Codes with SerpAPI, Gemini & Telegram

Promo Seeker automatically finds, verifies, and delivers active promo codes to users via Telegram or email using SerpAPI + Gemini (OpenRouter). Saves hours of manual searching and deduplicates results into an n8n Data Table for fast reuse.

Why Use This Workflow?

Time Savings: Reduces manual promo hunting from 2 hours to 5 minutes per query.

Cost Reduction: Cuts reliance on paid scraping tools or manual services — potential savings of $50–$200/month.

Error Prevention: Cross-references sources and enforces a 30‑day recency filter to reduce expired-code hits by ~60% vs single-source checks.

Scalability: Handles hundreds of queries per day with Data Table upserts and optional scheduling for continuous discovery.

Ideal For

Marketing / Growth Managers:** Quickly discover competitor or partner discounts to promote in campaigns. Customer Support / Operations:** Respond to user requests with verified promo codes via Telegram or email. Affiliate / Content Teams:** Aggregate and maintain a clean promo feed for newsletters or site widgets.

How It Works

Trigger: Incoming request via Webhook, Telegram message, Google Form submission, or scheduled run. Data Collection: The LangChain agent uses SerpAPI search results and Gemini (OpenRouter) to locate recent promo codes. Processing: Filter for recency (last 30 days), extract code, value, terms, and expiry. Intelligence Layer: Gemini 2.5 Pro (OpenRouter) + LangChain agent structure and verify results, outputting a standardized JSON. Output & Delivery: If a code exists in the Data Table, notify the requester via Telegram and Gmail; otherwise, return results and upsert them into the Data Table. Storage & Logging: Results stored/upserted in an n8n Data Table to prevent duplicates and enable fast lookups.

Setup Guide

Prerequisites

| Requirement | Type | Purpose | |-------------|------|---------| | n8n instance | Essential | Execute the workflow — import JSON to your n8n instance | | SerpAPI account | Essential | Web search results for promo code discovery | | OpenRouter (Gemini) account | Essential | Language model (Gemini 2.5 Pro) for extraction and verification | | Telegram Bot (BotFather) | Essential | Receive queries and send promo notifications | | Gmail OAuth2 | Essential | Send rich email notifications | | n8n Data Tables | Essential | Store and deduplicate promo code records |

Get your n8n instance here: n8n instance — import the JSON and begin configuration. (Repeat link for convenience) n8n instance

Installation Steps

Import the JSON workflow into your n8n instance. Configure credentials (use n8n's Credentials UI — do NOT paste keys into nodes): SerpAPI: paste your SerpAPI API Key from your SerpAPI dashboard. OpenRouter API: paste your OpenRouter API Key (for Gemini 2.5 Pro). Telegram API: create bot via @BotFather, then add Bot Token to Telegram credentials. Gmail OAuth2: use n8n's Gmail OAuth2 credential flow and authorize the account. Update environment-specific values: Webhook path: /v1/promo-seeker (configured in the Webhook node) or replace with your preferred path. Data Table ID: point to your own Data Table Form/webhook recipient fields (email/chatId mappings). Customize settings: Adjust the LangChain agent prompt (Promo Seeker Agent) for different recency windows or regional focus. Change max results/limit on the Data Table node (default limit = 3). Test execution: Trigger via Telegram or a POST to the webhook with sample payload: { "platform":"example.com", "email":"you@domain.com" } Confirm notifications arrive and Data Table rows are upserted.

Technical Details

Core Nodes

| Node | Purpose | Key Configuration | |------|---------|-------------------| | SerpAPI | Fetch web search results | Provide credential; adjust search params in agent prompt | | Gemini 2.5Pro (OpenRouter) | Extract & verify promo details | Use OpenRouter credential; model google/gemini-2.5-pro | | Promo Seeker Agent (LangChain) | Orchestrates search + parsing | System prompt enforces 30‑day recency & result format | | Structured Output Parser | Validates agent output | JSON schema example for platform/code/value/terms/validUntil | | Data Table (Get row(s)) | Lookup existing promos | Filters by platform; limit = 3 | | If (Code Exist?) | Branching logic | Checks existence of platform field | | Data Table (Upsert row(s)) | Insert or update promo | Mapping from agent output to Data Table columns | | Telegram Trigger / Telegram | Receive queries & notify users | Webhook-based trigger; parse_mode = HTML for messages | | Gmail | Send rich HTML emails | Uses Gmail OAuth2 credential | | Webhook / Form Trigger | Alternate inputs | Webhook path /v1/promo-seeker and Form trigger for manual submissions |

Workflow Logic

On trigger, the Platform Set node normalizes the incoming query and receiver. Get row(s) checks Data Table for existing promos. If found: notify via Telegram and send Gmail (email template included). If not found: the Promo Seeker Agent runs SerpAPI searches, parses structured output, then Upsert row(s) saves results and notifications are sent. Structured Output Parser enforces correct JSON to avoid bad upserts.

Customization Options

Basic Adjustments Recency window: change the agent prompt to 7/14/30 days. Result limit: increase Data Table Get limit or change Upsert batch size.

Advanced Enhancements Add Slack or Microsoft Teams notifications (moderate complexity). Add caching layer (Redis) to reduce repeated SerpAPI calls (advanced). Parallelize searches across multiple search engines (higher API usage & complexity).

Performance & Optimization

| Metric | Expected Performance | Optimization Tips | |--------|----------------------|-------------------| | Execution time | 8–30s per new search (depends on SerpAPI + LM response) | Reduce SerpAPI page depth; cache recent results | | API calls | 3–10 SerpAPI calls per complex query | Batch queries; use higher-quality search params | | Error handling | Agent retries on malformed output | Use retry nodes and set onError strategy for downstream nodes |

Troubleshooting

| Problem | Cause | Solution | |---------|-------|----------| | No results returned | Query too vague or rate-limited API | Improve query specificity; check SerpAPI quota | | Gmail send fails | OAuth scope not granted or token expired | Reconnect Gmail OAuth2 credential in n8n | | Telegram webhook not firing | Incorrect bot token or webhook setup | Recreate Telegram credential and check bot permissions | | Duplicate rows | Upsert mapping mismatch | Ensure promoCode mapping in Upsert matches structured output | | Agent returns malformed JSON | LM prompt too permissive | Tighten the agent system prompt and validate with Structured Output Parser |

Created by: khaisa Studio Category: Marketing Automation

Tags: promo-codes, coupons, serpapi, telegram, gmail, openrouter, data-tables

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