A WhatsApp conversation can count as evidence, but its effectiveness depends on how it is obtained, preserved and submitted.
WhatsApp screenshots arrive at the courts every week: threats, agreements, fraud or coercion are today argued over through messaging conversations. The short answer is yes, a WhatsApp conversation can count as evidence at trial, but its effectiveness depends on how it is obtained, preserved and submitted. In this guide we explain how to do it properly and what to expect if the other party challenges the messages.
Is it lawful to submit a WhatsApp conversation?
If you are a participant in the conversation, you may submit it. A participant in a communication does not breach the secrecy of communications by disclosing it (settled doctrine since Constitutional Court judgment STC 114/1984). Accessing a third party’s phone or account without their consent or judicial authorisation is a different matter: that evidence would be unlawful and could constitute an offence of discovery and disclosure of secrets.
The problem with screenshots: STS 300/2015
The Supreme Court warned in judgment STS 300/2015 of 19 May that messages from social networks and instant messaging are easy to manipulate, so if the other party challenges their authenticity, the screenshot is not enough: a computer forensic report will be needed to establish the origin, integrity and absence of manipulation of the conversation. In practice, this means that a simple printed screenshot has weak evidentiary value where there is a dispute. Reinforce the evidence before reaching trial.
How to submit WhatsApp correctly
Preserve the original device with the conversation intact: it is the source of the evidence. Certified forensic extraction: a computer expert downloads the conversation with a hash code and chain of custody. Notarial certificate: the notary examines the conversation on the phone itself and records its content. Transcription with verification: verification by the Court Clerk can be requested. Witness evidence from the participants confirming the exchange of messages.
What happens if my messages are challenged?
A challenge does not automatically expel the evidence: it obliges you to reinforce it. The court will weigh the expert report, the metadata, the consistency with other evidence and the witness statements. That is why it pays to anticipate and not depend solely on screenshots.
Frequent mistakes
Deleting the conversation from the phone after taking the screenshot. Submitting cropped captures or captures without context: they make challenges easier. Accessing the other person’s phone to obtain the messages. Waiting until trial to raise the expert report, when the device is no longer available.
Quick questions
Is a screenshot valid as evidence? It can be admitted, but if it is challenged you will need a computer forensic report establishing its authenticity (STS 300/2015).
Can I use messages from a group I take part in? Yes. As a participant you may submit the conversation; the same authenticity precautions apply.
What about WhatsApp voice notes? They are also electronic evidence: they are submitted with a forensic extraction and, if the voice is disputed, a speaker-identification expert report is available.
Related: technology crime FAQ, digital evidence in criminal cases and challenging audiovisual evidence and deepfakes.
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Francisco Javier Martín Porras
Abogado penalista, socio de Société de Conseil Juridique et Expert y creador de la metodología LIWARD®. Dirige la defensa en procedimientos penales de alta complejidad, combinando estrategia procesal con análisis pericial y forense. Conozca al equipo →
