Guides

How to choose an astrology API

This page is a set of questions to ask before you commit to an astrology API. The page does not compare named providers, and does not rank one provider against another.

The value here is the evaluation framework itself. Apply the framework to whatever candidates you are looking at, including this API.

Endpoint coverage for your product scope

Astrology APIs bundle several distinct suites:

• Vedic (sidereal) calculations
• Western (tropical) calculations
• Horoscope text content
• PDF report generation
• Palm reading

Figure out which suites your product actually uses before you compare anything else.

A wide catalog that includes suites you will never call is not a feature. The extra catalog is surface area you have to read past to find what matters.

Match the suite to the product, not the other way around. If your product is Vedic-only, the depth of a provider's Western tropical suite tells you nothing about fit. If your product is Western-only, the reverse is true.

How to test this in an afternoon

• Write down every astrology feature your product roadmap needs for the next two quarters.
• Pull the candidate's actual endpoint list and mark which features map to a direct endpoint versus which you would have to compute yourself.
• Note any suite you're being sold (palm reading, PDF generation, a full Western package) that doesn't map to a near-term feature.

Calculation transparency

Sidereal (Vedic) astrology depends on which ayanamsha a calculation uses. The ayanamsha is the offset between the tropical and sidereal zodiac.

A provider may not be able to tell you which ayanamsha applies to a given result. That provider hands you a chart you cannot audit.

You also cannot explain that chart to a user who asks why their sign differs from what another app showed them.

As a self-check: AstrologyAPI's ayanamsha endpoint returns six named systems for a given birth moment. Each system comes back as a plain numeric degree: LAHIRI, KP, YUKTESHWAR, RAMAN, JN_BHASIN, and FAGAN_BRADLEY.

Sidereal results elsewhere in the API (planets) use the Lahiri value. Tropical results (planets/tropical) skip the ayanamsha step entirely.

Whatever provider you evaluate, look for this same kind of auditable output. Look for a number you can check, not just a label you have to trust.

How to test this in an afternoon

• Ask which ayanamsha system the candidate uses for sidereal (Vedic) output, and whether you can retrieve the numeric value, not just the resulting sign.
• Compute the same birth record under two different sidereal systems the provider supports and confirm the sign or degree shifts are visible and explainable.
• Confirm you can pull raw planetary degrees, not only interpreted labels, so you can audit a result independently of the provider.

Data shape and completeness

A single call that returns everything your UI needs is worth more than several calls that each return a fragment.

Check whether one response includes the fields you will actually render. The alternative is stitching together multiple calls and response shapes to build one screen.

As a reference point: AstrologyAPI's planets endpoint returns, per planet, the zodiac sign, nakshatra, house, speed, and retrograde status (isRetro) in one response element.

If a typical natal-chart screen needs sign, nakshatra, and house per planet, that screen takes one call instead of three. Check whatever candidate you are evaluating against the same bar.

How to test this in an afternoon

• Sketch the exact fields your main chart screen needs to render, per planet.
• Make one real request against the candidate with a fixed birth record and count how many of those fields come back in a single response.
• Count how many additional calls you'd need to fill the gaps, and estimate the latency and error-handling cost of each one.

Auth and integration model

Ask how requests are authenticated and where the API key has to live.

AstrologyAPI uses HTTP Basic auth over server-side POST requests. Your user ID is the username and your API key is the password.

The API does not return CORS headers, so a call straight from a browser fails.

The CORS block is a deliberate trade-off, not a gap. An API you cannot call directly from client-side JavaScript keeps your API key safe, because the API key never leaves your server.

Plan for a backend layer that holds the API key and forwards the request. A Next.js API route, a small proxy service, or whatever fits your stack works.

Your product may need a client to call an astrology API directly. Check whether the provider supports a scoped token instead of the raw API key.

See the access token usage guide for how this API handles that case.

How to test this in an afternoon

• Send one authenticated request from your own server and confirm the auth header format.
• Send the same request directly from a browser console and confirm whether it is blocked, and whether the failure is a CORS block or something else.
• Check whether the provider offers a client-safe auth path (a short-lived token, for example) if your product needs to call the API from a browser or mobile client directly.

Content vs computation

Astrology APIs mix two kinds of endpoints:

• Computation: planetary positions, house cusps, deterministic math from birth data.
• Content: horoscope text, PDF report copy, written output tied to a template or generation pipeline.

The two kinds have different maintenance profiles.

Computation output for a fixed birth record does not change. You can cache that output indefinitely.

Content output, a daily horoscope string for a given sign, changes on a schedule. Content output also depends on the provider continuing to produce it.

Know which kind each endpoint you rely on actually is. That kind decides your caching, refresh, and cost model.

How to test this in an afternoon

• Classify each endpoint you plan to call as computation or content.
• For a content endpoint, request the same input twice a day apart and confirm the output changes.
• For a computation endpoint, request the same input twice and confirm the output is identical, then design your cache around that.

Pricing model fit

Subscription pricing and pay-as-you-go pricing fit different traffic shapes. A subscription with a fixed monthly credit pool fits steady, predictable volume.

Metered billing fits spiky or unpredictable traffic, where paying for unused headroom does not make sense. Match the pricing model to your actual traffic shape, not the reverse.

See the pricing page for the current plan structure.

How to test this in an afternoon

• Estimate your expected monthly call volume and how much it varies week to week.
• Compare that estimate against each candidate's plan structure: fixed monthly credits versus metered billing.
• Model the cost at twice and half your estimate, since real traffic rarely matches a forecast exactly.

Track record and scale

Ask for a real number, not an adjective. By our own reporting, AstrologyAPI serves 3,000+ businesses across 300+ endpoints.

The same reporting shows 100M+ calls a day at a 99.99% uptime SLA.

Whatever provider you are evaluating, ask for the equivalent figures. Treat the absence of a specific number as its own answer.

How to test this in an afternoon

• Ask for a specific, current uptime figure and what happens contractually if it is missed.
• Ask how long the provider has run the specific endpoints you plan to use, not just how long the company has existed.
• Check whether the provider publishes a status page or an incident history.

Support and docs quality

Docs quality tends to predict support quality, since both come from the same team's discipline. Before you commit to any provider, run through the onboarding yourself. A sales conversation is not a substitute.

Try AstrologyAPI's own quick start guide as one example of what to look for. Hold whatever else you are evaluating to the same bar.

How to test this in an afternoon

• Follow the candidate's quick start end to end with a fresh account, and time it.
• Search their docs for one specific response field from an endpoint you plan to use and confirm it is documented, not just implied by an example.
• Send one real support question before you sign anything, and note the response time and whether it answers the actual question.

Evaluation checklist

A plain checklist you can run against any candidate, mapped to the criteria above.

• ☐Every near-term roadmap feature maps to a real endpoint, not a suite you have to build calculation logic on top of.
• ☐You know which ayanamsha (or tropical/sidereal choice) applies to each sidereal result, and can retrieve the numeric value.
• ☐A single call returns the fields your main screen needs, or you have priced in the extra calls that fill the gap.
• ☐You know the auth model, whether CORS blocks browser calls, and where the API key will live in your architecture.
• ☐You have separated computation endpoints (cache indefinitely) from content endpoints (refresh on a schedule) in your integration plan.
• ☐The pricing model (subscription or metered) matches your actual traffic shape, not just your best-case forecast.
• ☐You have a specific uptime figure and incident history, not a marketing adjective.
• ☐You completed the quick start yourself, with a fresh account, before signing anything.
• ☐You sent one real support question and judged the response, not just the sales pitch.

Where to go next

Run the endpoint-coverage and docs-quality checks against this API specifically:

• Start with the quick start guide for a first authenticated request.
• Browse the full guides index for build-oriented tutorials.
• Read the production checklist for what changes once you move past evaluation and into real traffic.