What is Payment Gateway?
Payment gateway explained in plain English. See how it works with invoicing, transaction fees, popular providers, and how small businesses can start accepting online payments.
What Is a Payment Gateway?
A payment gateway is a technology service that securely captures and transmits payment information between a customer and a merchant, authorizing credit card or bank transfers and facilitating the movement of funds. Every time someone pays for something online — whether it's a product, service, or invoice — a payment gateway is working behind the scenes to make it happen. In the context of freelancing and small business, payment gateways are what turn your online invoice into a real, funded transaction. Without one, your clients have no digital way to send you money beyond a slow bank wire or paper check.
How Payment Gateways Work
A payment gateway transaction follows a clear path, usually completing in 2–5 seconds: Step 1: Customer enters card details Your client clicks "Pay Now" on your invoice and enters their credit card number, expiration date, CVV, and billing address into a secure checkout form. Step 2: Gateway encrypts and sends to processor The payment gateway SSL-encrypts the card data and sends it to the payment processor (like Stripe, PayPal, or Square). The gateway acts as the secure courier. Step 3: Processor routes to card network The processor forwards the transaction to the appropriate card network (Visa, Mastercard, Amex) which routes it to the issuing bank (the client's bank). Step 4: Authorization or decline The issuing bank either approves (authorization code) or declines the transaction and sends the response back through the chain to the gateway. Step 5: Merchant receives confirmation Within seconds, you see "Payment Approved" in your dashboard. The funds are typically deposited into your merchant account within 1–2 business days (or instantly with some providers).
Key Features of Payment Gateways
- Encryption (SSL/TLS) — protects card data in transit - Tokenization — replaces sensitive card data with a secure token for storage - Fraud detection — flags suspicious transactions using AI and rule-based filters - Multi-currency support — accepts international payments - Recurring billing — automates subscription and retainer payments - ACH support — processes bank transfers (slower but lower fees than cards)
How Payment Gateways Relate to Invoicing
When you send an invoice through Eonebill, clients can pay via credit card, debit card, or bank transfer. The payment gateway is what makes this possible. The moment your client hits "Pay," the gateway springs into action. For freelancers, the gateway choice affects: - Your fees — typically 2.9% + $0.30 per transaction for credit cards; ACH runs $0.25–$1 per transfer - Your settlement speed — Stripe and Square often fund same-day; others take 1–3 days - Client experience — a smooth, fast checkout reduces payment delays - International clients — some gateways support more currencies than others
Example: Payment Gateway in an Invoice
Freelance writer Marcus sends a $2,500 invoice to a corporate client for a whitepaper project. The invoice, created in Eonebill, includes a "Pay with Card" button powered by Stripe's payment gateway. The client's accounts payable processes the invoice and enters their corporate Visa card. Within 4 seconds, Stripe's gateway authorizes the $2,500 charge, deposits the funds into Marcus's Stripe account (minus $72.50 in fees), and Marcus sees the payment confirmed in his Eonebill dashboard. Total time: under a minute. Compare that to waiting 30–45 days for a paper check to arrive by mail.
Popular Payment Gateways for Small Business
| Gateway | Transaction Fee | Best For | Notes | |---|---|---|---| | Stripe | 2.9% + $0.30 | Online invoices, SaaS | Industry standard for freelancers | | PayPal | 2.9% + $0.30 | Clients who already use PayPal | Brand recognition helps trust | | Square | 2.6% + $0.10 | In-person + online | Simple, good for retail | | Braintree | 2.9% + $0.30 | Higher volume merchants | PayPal subsidiary | | ACH (via Stripe) | 0.8% (max $5) | Large invoices, B2B | Much cheaper than cards for $500+ |
Choosing the Right Gateway for Your Invoicing
For most freelancers sending online invoices, Stripe is the default recommendation — it's fast, reliable, widely trusted, and integrates directly with invoicing platforms like Eonebill. If you frequently invoice large corporate clients, consider enabling ACH payments to save significantly on transaction fees for invoices over $500. Pro tip: Never pass credit card processing fees to your clients unless you've clearly disclosed this in your contract. It can create friction and damage client relationships. Accept online payments on every invoice you send. Start your free Eonebill trial — built-in payment gateway means your clients can pay in seconds, not weeks. Want to understand how the money actually gets to your bank? Learn about payment processing and how transaction fees work. View Pricing → | Glossary Home → | Home →