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Personalised Compatibility API

We cover all aspects of compatibility be it Love, Friendship or Karma & Destiny.

We offer both summarised as well as detailed calculations along with interpretations.

Synastry

Synastry horoscope

Determine the strength and weakness in a relationship with Synastry horoscope API. The API evaluates natal charts based on aspects formed between two superimposed natal charts.

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Love compatibility interpretations

Get the detailed and expert interpretations for love compatibility. The API provides various potential and challenging aspects that helps determine the stability of relationship.

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Karma and destiny report

Access the karmic and destined journey details with Karma and destiny API.

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Get started with AstrologyAPI

Create a free account and test every endpoint with free credits. No credit card needed.

Friendship report based on Synastry

Check how well friendship grows with frienship report API. The API calculates the smoothness in the friendship based on synastry.

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Compare two birth charts with one API

Synastry is the study of how two birth charts relate to each other. Astrologers use it to read love, friendship and family bonds. Our Synastry API does the chart maths for both people and returns JSON.

You send two sets of birth details in one request. Fields that start with p_ describe the first person. Fields that start with s_ describe the second person.

Pick the depth you need. A sign match is quick and needs only zodiac signs. A full chart or report needs the full birth details of both people.

  • Both charts

    Planet signs, degrees and houses for each person, returned as first and second.

  • Composite chart

    A composite chart blends two charts into one shared chart. We return its planets, houses, ascendant, midheaven and aspects.

  • Love report

    Short paragraphs on how the pair connects in love, from shared interests to possible friction.

  • Friendship report

    Advice on how two friends talk to each other and where they may clash.

  • Karma and destiny

    A short reading on a possible past-life bond between the two people.

  • Sign compatibility

    A report and a percentage from two sun signs, or from sun and rising signs. The rising sign is the sign on the eastern horizon at birth.

Synastry and compatibility endpoints

Chart and report calls are POST requests with p_day, p_month, p_year, p_hour, p_min, p_lat, p_lon and p_tzone for one person. The same fields with s_ cover the other person. Sign match calls take the signs in the URL instead.

Base URL: https://json.astrologyapi.com/v1

POST/synastry_horoscope

Both charts and the composite

We return the planets for the first and second person, plus a composite chart with its own houses and aspects. The aspects in this response describe the composite chart.

1{
2  "first": [
3    { "name": "Sun", "norm_degree": 1.0791, "sign": "Aquarius", "house": 4 },
4    { "name": "Moon", "norm_degree": 29.1477, "sign": "Leo", "house": 10 }
5  ],
6  "second": [
7    { "name": "Sun", "norm_degree": 21.8862, "sign": "Pisces", "house": 5 },
8    { "name": "Moon", "norm_degree": 6.4311, "sign": "Libra", "house": 12 }
9  ],
10  "composite": {
11    "planets": [
12      { "name": "Sun", "norm_degree": 26.4826, "sign": "Aquarius", "house": 4 }
13    ],
14    "ascendant": 233.08651500000002,
15    "aspects": [
16      {
17        "aspecting_planet": "Sun",
18        "aspected_planet": "Venus",
19        "type": "Semi Sqaure",
20        "orb": 4.83
21      }
22    ]
23  }
24}
Read the /synastry_horoscope reference →
POST/love_compatibility_report/tropical

Love compatibility report

A list of short paragraphs on the couple’s strengths and weak spots. Show it as a relationship reading inside your app.

1{
2  "love_report": [
3    "An adventuresome bent is the focus between you two. That experimental flair isn't just confined to your sexual expression, either; any project you work on together is touched by creative magic. You are the idea person and your partner is the one to take them and run with them, making them become real."
4  ]
5}
Read the /love_compatibility_report/tropical reference →
POST/friendship_report/tropical

Friendship report

Plain advice on how two friends get along, what may cause friction and how to handle it.

1{
2  "friendship_report": [
3    "At first this can manifest as criticism of their efforts. You feel that you're being helpful and offering practical advice, but to your buddy it feels as if you don't like their work at all, nor do you have faith that they will be successful in these endeavors. You'll send out disapproving signals which your buddy will pick up immediately. So stop trying to push the relationship in a direction it may or may not naturally take; lighten up, and concentrate on nothing more than enjoying your friend's company."
4  ]
5}
Read the /friendship_report/tropical reference →
POST/zodiac_compatibility/:zodiacName/:partnerZodiacName

Quick sign match

Put two zodiac signs in the URL, such as aries. We return a short report and a compatibility_percentage. No birth time is needed.

1{
2  "your_sign": "Aries",
3  "your_partner_sign": "Aries",
4  "compatibility_report": "Aries need independence , freedom and excitement. They will easily understand their partner’s similar needs. Their partnership can be extremely powerful if they resist the urge to compete with each other. Two Aries will have a fun filled relationship, they will appreciate each other's spontaneity and will never be bored.  Their relationship is a passionate one and indeed highly compatible.",
5  "compatibility_percentage": 75
6}
Read the /zodiac_compatibility/:zodiacName/:partnerZodiacName reference →

Who uses compatibility data

More than 3,000+ businesses build on AstrologyAPI. These are common ways they use two-chart data.

Dating apps

Show a quick sign match on each profile. Offer the full love report once two people connect.

Building compatibility into a dating app →

Astrology apps

Let users add a partner or a friend, then read how their two charts compare.

Natal Chart API →

Report sellers

Sell a couple report as a branded PDF with your own logo.

Western PDF Report API →

Astrology writers and teachers

Explain the difference between synastry and composite charts with real data.

Composite and synastry charts explained →

Synastry API FAQ

What is a synastry API?

It compares the birth charts of two people. You send both sets of birth details in one request. We return each chart, a composite chart and readable compatibility reports.

What does synastry_horoscope return?

It returns first and second, the planet lists for each person. It also returns composite, a blended chart with its own planets, houses and aspects. Those aspects belong to the composite chart. They are not angles between one person’s planets and the other’s.

Which relationship reports do you offer?

Love compatibility, friendship, karma and destiny, and a romantic forecast for couples. Each one is its own endpoint and returns readable paragraphs.

Can I match two people without birth times?

Yes, at a simple level. zodiac_compatibility takes two sun signs in the URL. If you also know both rising signs, the compatibility endpoint takes all four signs. Both return a report and a compatibility percentage.

Which languages are supported?

synastry_horoscope supports English, Spanish, Portuguese, French, Italian, German and Russian. The compatibility report endpoints return English.

Do you also offer Vedic matching?

Yes. Our Kundli Matching API covers the Vedic way of matching two charts. You can offer both styles in the same app.

Ready to add this to your app? See our plans and pricing.