API authentication basics
How API keys, bearer tokens and OAuth differ — and what to choose for marketplace integrations.
Practical how-to articles published by APISeeker. Providers do not publish marketplace guides.
Step 1
Most marketplace APIs start with an API key in a request header (for example X-API-Key). Keep keys server-side and rotate them from the dashboard.
Step 2
API keys identify a caller and apply quotas. They are not a substitute for end-user login when your product has many customers.
Step 3
OAuth is better when an end user grants access to their account at a provider. APISeeker marketplace keys are typically for your application, not end-user OAuth.
Step 4
Never commit keys to git. Prefer environment variables and short-lived test keys in playgrounds.
Step 5
If a key is leaked, revoke it immediately and create a replacement before deploying again.
Key takeaways
- Most marketplace APIs start with an API key in a request header (for example X-API-Key). Keep keys server-side and rotate them from the dashboard.
- API keys identify a caller and apply quotas. They are not a substitute for end-user login when your product has many customers.
- OAuth is better when an end user grants access to their account at a provider. APISeeker marketplace keys are typically for your application, not end-user OAuth.
- Never commit keys to git. Prefer environment variables and short-lived test keys in playgrounds.
Keep learning
- GuideHow to validate a GSTIN using an APIStep-by-step guide to call the GSTIN Verification API, handle errors and store results safely.
- GuideInvoice OCR API integration guideExtract vendor, totals and line items from invoice PDFs with confidence-aware parsing.
- GuideHow to build a GST verification workflowDesign an onboarding flow that combines GSTIN checks, retries and audit logging.
- GuideAPI keys vs OAuthA practical decision guide for developers integrating third-party APIs.
Ready to integrate?
Compare plans, open docs, and try endpoints in the playground — then create a key when you are ready for production traffic.