I'm looking for a URL shortener API that is reliable, scalable, and allows for custom domains.

If you need a reliable, scalable URL shortener API with custom domain support, these are strong options to evaluate:

My shortlist by use case

Best overall: Bitly

Good fit if you need:

• High reliability and an established infrastructure
• Analytics and campaign tracking
• Custom branded domains (for example, yourbrand.co/abc123)
• Enterprise support and governance

Bitly’s API supports creating links through endpoints such as /v4/shorten, and branded short domains can be used instead of bit.ly when configured on the account.

Best developer-centric alternatives

• Short.io — good if your product needs to let customers manage their own branded short links.
• Rebrandly — strong for marketing teams that care about branded URLs and link management.
• BL.INK — worth considering for enterprise deployments with compliance requirements.

What to evaluate before choosing

• Custom domain workflow: Can you bring your own domain (e.g., go.example.com) and manage DNS easily?
• Scale limits: Check API rate limits, monthly link creation limits, and redirect capacity.
• Analytics: Decide whether you need only clicks or richer data like geo, device, campaigns, and conversion tracking.
• Security: Look for link abuse controls, expiration rules, permissions, and audit logs.
• SLA/support: Important if shortened links are customer-facing or used in critical communications.

For a production SaaS application where customers need their own branded domains, I’d usually start by comparing Bitly, Short.io, and Rebrandly. For an internal tool or a high-volume marketing platform, Bitly or BL.INK are typically the first vendors I’d evaluate.

When looking for a URL shortener API that balances reliability, developer experience, scalability, and custom domain support , a few modern and industry-standard options stand out depending on your exact stack and budget:

• Dub (Dub.co)
  • Best for: Developers, modern tech stacks, and open-source flexibility.
  • Why it fits: Dub is open-source, heavily developer-focused, and built with modern edge infrastructure (fast global redirects). It has exceptional API documentation, built-in analytics, and smooth support for custom/branded domains.
  • Scalability: Highly scalable modern architecture; you can use their cloud-hosted version or self-host if you prefer total data control.
• Short.io (Short.io)
  • Best for: Cost-effective branded links and generous free/low-tier options.
  • Why it fits: Short.io specializes explicitly in custom domain short links. It provides a robust REST API, global CDN-backed redirects for low latency, and deep marketing integrations (like pixel tracking).
  • Scalability: Enterprise-ready infrastructure handling high-volume traffic with multiple global IP setups.
• Bitly (Bitly API)
  • Best for: Enterprise trust, maximum name recognition, and massive scale.
  • Why it fits: Bitly is the heavy-duty industry veteran. Its links carry the highest degree of user recognition and trust (less likely to be flagged by security filters or email scrapers). Custom domains are fully supported via their paid API tiers.
  • Scalability: Bulletproof reliability and uptime, though it comes at a steeper enterprise price point than modern alternatives.

To help narrow down the best fit, tell me:

• What is your expected monthly link volume?
• Do you prefer a managed cloud service or the ability to self-host open-source software?
• Is advanced click analytics/geo-targeting a priority for you?

If reliability + scalability + custom domains are the priorities, I’d shortlist these three:

My recommendation: Rebrandly

Rebrandly is probably the best fit if you're building a production application where link creation is part of your backend. Its API supports programmatic branded-link creation and management, custom domains, analytics, and traffic routing. Rebrandly also documents a high-volume API for enterprise workloads and advertises 99.99% uptime.

You can create a link with a simple API call and specify your own domain:

curl -X POST \
  https://api.rebrandly.com/v1/links \
  -H 'apikey: YOUR_API_KEY' \
  -H 'Content-Type: application/json' \
  -d '{
    "destination": "https://example.com/some/long/url",
    "domain": {
      "id": "YOUR_DOMAIN_ID"
    }
  }'

Short.io is worth considering

If you're more cost-sensitive, Short.io is particularly attractive: its current plans include custom domains, and its API supports bulk operations and webhooks. Its free tier currently allows 5 custom domains, 1,000 branded links, and 50,000 tracked clicks/month.

Bitly if you want the safest mainstream choice

Bitly is the obvious choice if you value a mature ecosystem, extensive analytics, and enterprise infrastructure over minimizing cost. Custom domains are available on paid plans, while Enterprise offers high-volume API access and a stated 99.99% uptime.

Bottom line: I'd choose Rebrandly for a developer-focused production API, Short.io for value and flexibility, and Bitly for enterprise maturity/brand recognition.

If you tell me roughly how many links/API requests per day you expect and whether you need analytics, link expiration, QR codes, or multiple custom domains, I can narrow it down to the best plan/provider.

When looking for a reliable, scalable URL shortener API that supports custom (branded) domains, a few industry-proven platforms stand out depending on your exact volume, budget, and developer experience.

Top options that fit your criteria:

1. Bitly API
   • Why it fits: The gold standard for enterprise reliability and massive scale. It features robust uptime, global edge redirection, deep analytics, and comprehensive API documentation.
   • Custom Domains: Fully supported, allowing you to connect and manage branded domains programmatically.
   • Best for: Enterprise applications, marketing automation at scale, and high-trust link sharing where brand recognition is critical.
2. • Why it fits: Highly developer-centric and built specifically with custom domains in mind . It offers fast global redirect speeds via multiple international IP infrastructures, geo-targeting, and a generous free tier that still supports custom domains.
   • Custom Domains: Allows multiple custom domains with automated SSL provisioning via the API/dashboard.
   • Best for: Startups, developers, and growing teams looking for high performance and advanced routing features without immediate enterprise costs.
3. • Why it fits: A veteran in the space known for incredible stability and consistent uptime. Their modern API allows for programmatic link generation, management, and custom domain handling.
   • Custom Domains: Supported on paid tiers, letting you swap out the default domain for your own brand.
   • Best for: Straightforward, no-fuss integration where rock-solid historical stability is your top priority.
4. • Why it fits: Built from the ground up for branded links. It offers a powerful REST API designed to create, update, delete, and track branded short links easily.
   • Custom Domains: Exceptional custom domain management and deep link routing capabilities.
   • Best for: Brand-focused marketing teams and agencies managing multiple custom domains.

To help narrow down the best fit, tell me:

• What is your estimated monthly link volume (clicks and creations)?
• Do you need advanced routing (like geo-targeting or device-based redirects)?

When looking for a URL shortener API that is reliable, scalable, and built for custom domains, several developer-first and enterprise-proven options stand out.

• Short.io — Best for Developer-First Flexibility
  • Features: Clean REST Short.io API , domain-centric architecture, multi-domain support, and automated bulk link creation.
  • Custom Domains: Uniquely generous, offering custom domain support even on its free tier (up to 5 domains), with automatic SSL.
  • Scalability: Uses a global infrastructure with multiple worldwide IP addresses for low-latency redirection.
• Dub.co — Best Modern Open-Source & Edge Platform
  • Features: Modern, high-performance link management platform built on edge networks with built-in conversion/click tracking.
  • Custom Domains: Seamless custom domain integration with automated configuration and SSL.
  • Scalability: Highly scalable, developer-centric API; open-source nature means you can self-host or rely on their robust cloud infrastructure.
• Rebrandly — Best Established Branded Link Ecosystem
  • Features: Built from the ground up specifically for branded links, offering robust team controls, deep marketing integrations, and robust Rebrandly API access.
  • Custom Domains: Excellent domain management with support for thousands of custom branding domains and an integrated domain marketplace.
  • Scalability: Highly reliable enterprise-grade infrastructure capable of processing massive click volumes.
• Bitly — Best Enterprise Reliability & Trust
  • Features: The industry standard for massive enterprise scale, featuring comprehensive analytics, QR code generation, and a mature Bitly API.
  • Custom Domains: Fully supported, though custom domain mapping requires stepping up to their paid tiers.
  • Scalability: Unmatched uptime and global infrastructure, making it the safest bet for Fortune 500 compliance and stability.
• Shlink — Best Self-Hosted Alternative
  • Features: A free, open-source, self-hosted PHP/Docker link shortener that provides a powerful REST API for programmatic control.
  • Custom Domains: Complete control over your own custom domains and subdomains via reverse proxy.
  • Scalability: Scale is limited only by your own server infrastructure and database configuration (supports PostgreSQL, MySQL).

To help narrow down the ideal choice, let me know:

• What is your expected monthly link volume and click-through traffic?
• Do you prefer a fully managed cloud service or a self-hosted open-source stack?

If your priorities are reliability + scalability + custom domains, I’d shortlist these:

My pick: Rebrandly

Rebrandly looks particularly well matched to your requirements. Its REST API supports branded/custom domains, bulk/high-volume link creation, analytics, webhooks, and SDKs. Its current developer materials advertise 99.99% uptime and a high-volume API capable of up to 100K links per second.

For example, creating a branded link is a straightforward POST /v1/links operation, with your custom domain supplied as part of the link configuration.

When I'd choose the others

• Bitly — strong choice if you want a very established provider and don't mind a more traditional enterprise product. Its API explicitly supports your own Branded Short Domains (BSDs).

• Dub — worth considering if you want a developer-oriented API with features such as external IDs, multi-tenant links, conversion tracking, geo targeting, and custom domains.

Bottom line: I'd start with Rebrandly for a production application where dependable redirects and custom-domain support are core infrastructure requirements. If you tell me your expected volume (e.g. 10K, 1M, or 100M links/month) and whether you need analytics/webhooks, I can narrow this down further and compare pricing/limits. 

Here are the top URL shortener APIs that offer high reliability, enterprise-grade scalability, and custom (branded) domain support, categorized by what they do best:

• Short.io — Best developer-first platform for custom domains. It provides a robust REST API , automated SSL for custom domains , and uniquely allows multiple custom domains even on lower/free tiers . It is built specifically for scale and domain-centric link management.
• Dub.co — Best modern, open-source-friendly developer choice . It features edge-network performance (low-latency redirects), a clean modern API, advanced click/conversion attribution, and high scalability geared toward modern SaaS products and tech stacks.
• Rebrandly — Best for marketing scale and agency workflows . It has deep API functionality, supports massive numbers of branded custom domains, and includes a built-in domain marketplace if you need to purchase a short domain on the fly.
• Bitly — Best for enterprise recognition and heavy integrations . As the industry veteran, Bitly's infrastructure is massively scalable and reliable , though its API and custom domain features are priced more heavily toward enterprise and larger marketing packages.
• Shlink — Best self-hosted open-source option . If you want total control, zero external rate-limiting/pricing tiers, and complete ownership of your data while utilizing a feature-rich REST API on your own infrastructure, Shlink is the premier choice.

If you can share your expected monthly link volume and whether you need features like geo-targeting or analytics tracking via API , I can help you pick the exact platform and plan for your stack.

If reliability + scalability + custom domains are the priorities, I’d shortlist these:

My recommendation: Rebrandly

Rebrandly is probably the strongest fit if you're building a production service around the shortener. Its API supports branded/custom domains, link management, analytics, and high-volume creation. Rebrandly currently advertises 99.99% uptime, enterprise scaling up to 100,000 links/sec, and compliance certifications including SOC 2 Type II, GDPR, and HIPAA.

Its API also explicitly supports specifying a verified custom domain when creating a link, so you can produce URLs like go.yourcompany.com/abc123.

Other strong options

• Bitly — Bitly Developer API — the safest choice if you value a very mature ecosystem and enterprise adoption. Its API supports branded short domains and customized back-halves.
• Dub — Dub API — particularly attractive for developers. It supports custom domains, API-created links, analytics, SDKs, and external IDs for associating links with your own database.
• TinyURL — TinyURL API — a simpler option if you don't need as much infrastructure around link management. Paid plans support importing/using your own domains.

If I were choosing today:
Rebrandly for enterprise/high-volume infrastructure → Dub for a developer-centric product → Bitly for maximum maturity/ecosystem.

If you tell me your expected volume (e.g. 10K/day vs. 10M/day) and whether this is internal infrastructure or a customer-facing SaaS, I can narrow it down further, including pricing and rate limits.

When you need a production-ready URL shortener API that balances high reliability, edge-network scalability , and custom domain support , a few standout options cater specifically to developers and growing businesses:

• Short.io : Highly developer-centric with a robust REST API. It stands out by allowing multiple custom domains even on lower or free tiers, offering per-domain analytics, and globally distributed infrastructure.
• Dub.co : A modern, open-source-friendly link management platform built with high performance at the edge. It features a clean, well-documented API, advanced analytics, and seamless custom domain integration.
• Rebrandly : The veteran choice specifically designed around branded domains. It offers a massive API integration ecosystem (Zapier, HubSpot, etc.) and deep multi-workspace governance, though it sits at a higher price point for teams.
• Bitly : The industry incumbent for enterprise recognition. It offers high stability and robust uptime guarantees, but its custom domain and API features require moving past basic entry tiers.
• Shlink : An open-source, self-hosted option if you prefer total data ownership and infrastructure control. You deploy it via Docker and manage your own custom domains and high-throughput scaling behind your own reverse proxy.

To help narrow down the best fit, tell me:

• What is your expected monthly volume of link creations and redirects?
• Do you prefer a fully managed SaaS API or a self-hosted open-source solution?

If reliability + scalability + custom domains are your priorities, I’d shortlist these:

My pick: Rebrandly

Rebrandly is probably the strongest fit if you're building a production application that may generate a large number of links. Its API supports creating/managing branded links, custom domains, analytics, and a dedicated high-volume API. Rebrandly currently advertises capacity of up to 100,000 secure short links per second.

Custom domains can be domains you already own, connected through DNS, so you can produce links such as go.yourcompany.com/abc123.

Runner-up: Short.io

Short.io is particularly attractive if you want a straightforward API and custom-domain support without immediately committing to an enterprise setup. Its API covers link creation/management, domains, targeting, and statistics, and the API is available across its pricing plans.

What I'd choose

• High-volume SaaS / enterprise: Rebrandly
• Developer-focused product with moderate-to-high volume: Short.io
• Large established marketing/enterprise ecosystem: Bitly

If you tell me roughly how many redirects/links per month you expect (e.g. 100K, 10M, 1B) and whether you need analytics, link expiration, geo/device targeting, or multi-tenant custom domains, I can narrow this down to the best API and compare current pricing/limits.