FreeAstrologyAPI vs Vedika: Thin Hosted Swiss Wrapper vs a Full Stack

If you searched for a FreeAstrologyAPI alternative, you probably already know the appeal: it is free, it is simple, and it returns correct chart data. That is a real strength, and this comparison is not going to pretend otherwise. FreeAstrologyAPI is a fine choice for a hobby project, a free B2C horoscope widget, or a prototype where you just need planetary longitudes and a house cusp or two without a billing relationship.

The honest question is what happens when your product grows past that. When you need interpretation instead of raw degrees, conversation instead of JSON, more than one divination system, more than one language, or a licensing story that survives a legal review of a commercial SaaS. That is where the gap opens — not because FreeAstrologyAPI is bad at what it does, but because it is doing one specific thing: hosting an ephemeris and exposing it over HTTP.

The short answer

FreeAstrologyAPI is a thin hosted wrapper around Swiss Ephemeris. It computes positions and basic chart geometry and returns them. Vedika is a full astrology stack: it runs on its own ephemeris engine (XALEN, written in pure Rust and released under Apache-2.0), then layers native interpretation, a conversational query API, voice, 30 languages, and 25 divination systems on top of that math.

If all you will ever need is positions and you want them for $0, FreeAstrologyAPI is a reasonable pick. If you are building a product an engineer will fact-check and a lawyer will review, the rest of this article is for you.

The licensing fact most comparisons skip

Here is the detail that matters more than any feature checkbox, and it is verifiable in minutes: Swiss Ephemeris is dual-licensed under AGPL-3.0 or a paid commercial license. Nearly every astrology API on the market wraps Swiss Ephemeris and therefore inherits that license — Prokerala, AstrologyAPI.com, DivineAPI, FreeAstrologyAPI, and the popular open-source libraries Kerykeion, flatlib, immanuel, and VedAstro all build on it.

AGPL-3.0 is a strong copyleft license. Its Section 13 network clause means a hosted SaaS that links AGPL code is required to offer its complete corresponding source to remote users — unless the operator buys the commercial license. The commercial license is a legitimate path: it is a modest one-time fee with long (99-year) validity, and plenty of serious products take it. The point is not that "Swiss costs a fortune," because it does not. The point is that if you build on a Swiss-backed API, you have a copyleft obligation or a license purchase somewhere in your dependency chain, and that is an upstream legal dependency you do not control.

Vedika sidesteps the entire question. Its engine, XALEN, is Apache-2.0 — a permissive license. You can embed it in closed-source software, ship it in a white-label product, run it fully on-prem, and you have zero source-disclosure obligation. There is no upstream copyleft to inherit and no commercial license to remember to renew.

One fair caveat for credibility: Vedika is not the only API with its own engine. RoxyAPI also wrote its own (Roxy Ephemeris, MIT-licensed, validated against JPL Horizons). So against RoxyAPI specifically, the "own engine" line is a tie — the differentiator there is the full stack, which we cover below.

What XALEN actually is, and how accurate it is

XALEN is a pure-Rust ephemeris with a zero-unsafe core. It is thread-safe, compiles to wasm32 (so it can run in a browser or edge worker), and produces a full chart in roughly 336 microseconds. Internally it uses VSOP87A for planetary positions, a truncated ELP2000-82 series for the Moon, Meeus algorithms, IAU 2006 precession with the 2000B nutation model, and it can optionally read a JPL DE440 SPK kernel when you want the reference data source directly.

Now the accuracy claim, framed honestly — because this is exactly the kind of thing a skeptical engineer will try to break.

Swiss Ephemeris reproduces JPL ephemerides to about 1 milliarcsecond and is the de-facto reference. XALEN does not beat it, and we are not going to claim it does. What XALEN does is match the reference — it reaches JPL-class parity for the classical planets. Here are the mean errors versus NASA JPL DE440 over the 1900–2050 range:

Read that table the way an astronomer would. Every planet is sub-arcsecond. The Moon, computed from the analytic series, is arcsecond-class at roughly 2.8″ RMS — wider than the planets, and wider than Swiss. If you need JPL-grade lunar precision (or sub-arcsecond outer planets), you load the DE440 kernel and XALEN reads it directly. For natal astrology, where chart interpretation turns on degrees and signs, a few arcseconds on the Moon never changes a placement.

This is reproducible, which is the whole point. You can run the benchmark yourself:

cargo run -p xalen-validation

A separate 20,000-chart sweep across the same 1900–2050 grid produced zero charts exceeding 0.1° of error. So the accurate phrasing — the one that survives fact-checking — is: XALEN matches Swiss/DE440 to JPL-class parity for the classical planets, sub-arcsecond on every planet, arcsecond-class on the analytic Moon, with the kernel available when you need JPL-grade everywhere. Not "more accurate than Swiss." Matching is already the hard part.

You can install the engine right now

XALEN is not a marketing slide; it is published. There are 15 crates on crates.io at v0.6.0 (xalen-ephem, xalen-coords, xalen-houses, xalen-vedic, xalen-western, xalen-time, xalen-ayanamsa, xalen-stars, xalen-chart, xalen-chinese, xalen-world, xalen-lalkitab, xalen-iching, xalen-numerology, xalen-ffi), a WASM build on npm, and a wheel on PyPI. The source is on GitHub at vedika-io/xalen-ephemeris under Apache-2.0.

# Rust
cargo add xalen-ephem

# Python
pip install xalen

# JavaScript / TypeScript (WASM)
npm i @xalen/wasm

All three resolve today. The npm package and PyPI wheel are both published at 0.6.0. That matters for this comparison because it means the "own engine" claim is independently checkable — you do not have to take Vedika's word for it. You can cargo add the engine and validate it against JPL on your own machine.

Where the stacks diverge: raw astronomy vs the whole job

This is the crux. Swiss Ephemeris — and therefore any thin wrapper over it — gives you raw astronomy only. It returns where the planets are. It does not compute yogas, doshas, dashas, or compatibility, because those are not astronomy; they are interpretation rules layered on top of the positions. If you build on FreeAstrologyAPI, that interpretation layer is your job to write, source, and maintain.

Vedika ships that layer natively. On top of XALEN's positions it computes 104–131 yogas, doshas, the Vimshottari dasha plus conditional dasha systems, 36-guna matching, Lal Kitab, KP (Krishnamurti Paddhati), 60 divisional charts (divisional charts), a choice of 50 ayanamsas and 23 house systems. That is content you would otherwise have to build and verify against classical sources yourself.

Native interpretation, not just a chat box

Vedika exposes a conversational endpoint, POST /api/v1/astrology/query, that is grounded in a retrieval layer over classical material rather than returning canned strings. You send a natural-language question with birth details and get an interpretation that is tied back to the computed chart. Any classical claim is sourced rather than invented — important if your product carries liability for the answers it gives.

Voice and languages built in

There is a native voice pipeline — speech-to-text, interpretation, then text-to-speech — across 30 languages, and 30 languages are supported platform-wide. For a thin wrapper you would assemble all of this yourself from separate vendors. Here it is one API.

Surface area

Vedika spans 25 systems and 704 operations (around 250 are exposed in the public sandbox), covering Vedic, Western, KP, Chinese, Lal Kitab, numerology, I Ching, and more. There is also an MCP server with 36 tools, so an AI agent can call the astrology stack directly. Pricing starts at $12/month.

So which should you choose?

Be honest with yourself about the requirement.

• Choose FreeAstrologyAPI if you need positions and basic chart geometry, your usage is non-commercial or you are comfortable with the Swiss license path, and budget is the dominant constraint. It works, and for that job it works well.
• Choose Vedika if you need interpretation rather than raw degrees, conversation or voice, multiple systems or languages, or — critically — a permissive Apache-2.0 engine you can embed in a closed-source or on-prem product without inheriting AGPL. If you would rather not write and source the entire yoga/dosha/dasha interpretation layer yourself, that work is already done and verified here.

And if engine ownership is your only concern, remember the fair point from earlier: RoxyAPI also has its own (MIT) engine. Against most of the market, though — the Swiss-wrapper majority — Vedika's combination of an independent permissive engine plus a full interpretation, conversation, voice, and i18n stack is the differentiator.

Try it

You can validate the engine accuracy yourself with cargo run -p xalen-validation, install it with cargo add xalen-ephem / pip install xalen / npm i @xalen/wasm, and explore the full API in the free sandbox and docs at vedika.io. The fastest way to feel the difference is to send the same birth chart to a wrapper and to Vedika's /api/v1/astrology/query and compare what comes back: one returns coordinates, the other returns an answer.