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Product · EIS Fitting

Not just fitted spectra — interpreted EIS results, in minutes, at scale.

Each fit ships with a written interpretation: the circuit class, what the parameters imply, and the places the fit isn't safe to trust. Across one spectrum or a full archive.

Sign up + trySee methodologyFree credits at signup
EIS Fitting application — equivalent-circuit fit overlaid on a measured impedance spectrum, with residuals and fitted parameter ranges in view.

Walkthrough

  1. Step 01· Upload

    Upload.

    Upload your data, assign labels, and provide experimental context.

  2. Step 02· Visualize

    Visualize.

    Visualize your dataset in Bode or Nyquist representation.

  3. Step 03· Fit + interpret

    Fit and interpret.

    The assistant handles the fitting, identifies the most appropriate circuits, and discusses the possible interpretations with you.

  4. Step 04· Report and export

    Report and export.

    Generate high-quality figures via conversation with the assistant. The assistant then writes the report with figures and discussion.

§ 04 · Methodology

What the fit actually does — said plainly.

EIS Fitting is a propose–review loop wrapped around a non-linear least-squares fitter. The fitting algorithm class is named. The initial-guess strategy is named. The uncertainty estimator is named. Nothing here is opaque.

01Fitting algorithm class
Non-linear least-squares with bounded parameters. Implementation is open to inspection; we do not run a fitter whose objective function we will not show you.
02Initial-guess strategy
Spectrum-derived priors with bounded perturbation, not random restarts. We document why a given starting point was chosen and which parameters were locked during the first pass.
03Propose–review loop
The assistant proposes a topology and parameter set. You see the proposal — and the residuals — before the fit is committed to your run history. Accept, refine, or reject.
04Residuals · parameter uncertainty
Normalised residuals are reported alongside per-parameter uncertainty. A high-χ² fit with well-bounded parameters and a high-uncertainty fit with great-looking residuals are distinguished, not collapsed.
See full methodology

Pricing

Free credits
Free credits awarded at signup.
What a credit buys
What a credit buys: one full fit run.
Expiry
Credits never expire.
Renewal
No auto-renewal trap.
View pricing
  • Exports available
  • Account portable
  • Data deletable on request
  • What's stored vs ephemeral is documented per object

Your data is account-tied, not used to train models, deletable on request. See /data-handling

Related

Honest beta

The propose step's circuit-class library is being expanded; some specialty cells may fall back to manual circuit entry.

The fitting algorithm class, residuals, and per-parameter uncertainty are stable.

Free credits are sufficient to evaluate the workflow end-to-end on a representative spectrum.

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